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  • 1. Ali, A.
    et al.
    Rafique, A.
    Kaleemullah, M.
    Abbas, G.
    Ajmal Khan, M.
    Ahmad, M. A.
    Raza, Rizwan
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik. Chinese Academy of Sciences, China.
    Effect of Alkali Carbonates (Single, Binary, and Ternary) on Doped Ceria: A Composite Electrolyte for Low-Temperature Solid Oxide Fuel Cells2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 1, s. 806-818Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Samarium-doped ceria (SDC) carbonate has become an attractive electrolyte for fuel cells because of its remarkable ion conductivity and high performance. Different doped ceria-carbonate (single-carbonate SDC, binary-carbonate SDC, and ternary-carbonate SDC) electrolytes were synthesized by the coprecipitation/oxalate method, to optimize the electrochemical performance. The structure; morphology; and thermal, optical, and surface properties have been studied using a variety of techniques. The X-ray diffraction results confirmed the successful incorporation of samarium into ceria as a crystalline structure and inclusion of carbonate, which is amorphous in nature. To analyze the conduction mechanism, direct current conductivity was measured in a H2/O2 atmosphere. Doped ceria-binary carbonate ((Li/Na)CO3-SDC) showed the best conductivity of 0.31 S cm-1 and power density of 617 mW cm-2, at 600 °C. The enhancement in the ionic conductivity and performance of the composites is due to the contribution of hybrid ions (O2-, H+). The crystallite size of the composites was in the range 21-41 nm. For the calculation of band gaps, optical absorption spectra of the synthesized powders were analyzed, and they showed a red shift with the band gap energy in the range 2.6-3.01 eV, when compared to that of pure ceria (3.20 eV).

  • 2.
    Alipour, Nazanin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Andersson, Richard L.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Olsson, Richard T.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Gedde, Ulf W.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    VOC-Induced Flexing of Single and Multilayer Polyethylene Films As Gas Sensors2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 15, s. 9946-9953Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The differential swelling and bending of multilayer polymeric films due to the dissimilar uptake of volatile organic compounds (VOCs; n-hexane, limonene) in the different layers was studied. Motions of thin polyethylene films triggered by the penetrant were investigated to learn more about how their deformation is related to VOC absorption. Single layers of metallocene or low-density polyethylene, and multilayers (2-288-layers) of these in alternating positions were considered. Single-, 24-, and 288 layer films displayed no motion when uniformly subjected to VOCs, but they could display simple curving modes when only one side of the film was wetted with a liquid VOC. Two-layer films displayed simple bending when uniformly subjected to VOCs due to the different swelling in the two layers, but when the VOC was applied to only one side of the film, more complex modes of motion as well as dynamic oscillations were observed (e.g., constant amplitude wagging at 2 Hz for ca. 50 s until all the VOC had evaporated). Diffusion modeling was used to study the transport behavior of VOCs inside the films and the different bending modes. Finally a prototype VOC sensor was developed, where the reproducible curving of the two-layer film was calibrated with n-hexane. The sensor is simple, cost-efficient, and nondestructive and requires no electricity.

  • 3. Al-Shammari, Rusul M.
    et al.
    Baghban, Mohammad Amin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Al-attar, Nebras
    Gowen, Aoife
    Gallo, Katia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Rice, James H.
    Rodriguez, Brian J.
    Photoinduced Enhanced Raman from Lithium Niobate on Insulator Template2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 36, s. 30871-30878Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Photoinduced enhanced Raman spectroscopy from a lithium niobate on insulator (LNOI)−silver nanoparticle template is demonstrated both by irradiating the template with 254 nm ultraviolet (UV) light before adding an analyte and before placing the substrate in the Raman system (substrate irradiation) and by irradiating the sample in the Raman system after adding the molecule (sample irradiation). The photoinduced enhancement enables up to an ∼sevenfold increase of the surface-enhanced Raman scattering signal strength of an analyte following substrate irradiation, whereas an ∼threefold enhancement above the surface-enhanced signal is obtained for sample irradiation. The photoinduced enhancement relaxes over the course of ∼10 h for a substrate irradiation duration of 150 min before returning to initial signal levels. The increase in Raman scattering intensity following UV irradiation is attributed to photoinduced charge transfer from the LNOI template to the analyte. New Raman bands are observed following UV irradiation, the appearance of which is suggestive of a photocatalytic reaction and highlight the potential of LNOI as a photoactive surface-enhanced Raman spectroscopy substrate.

  • 4.
    Anoshkin, Ilya V.
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Campion, James
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Lioubtchenko, Dmitri V.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Oberhammer, Joachim
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Freeze-Dried Carbon Nanotube Aerogels for High-Frequency Absorber Applications2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, ISSN 1944-8244, Vol. 10, nr 23, s. 19806-19811Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel technique for millimeter wave absorber material embedded in a metal waveguide is proposed. The absorber material is a highly porous carbon nanotube (CNT) aerogel prepared by a freeze-drying technique. CNT aerogel structures are shown to be good absorbers with a low reflection coefficient, less than -12 dB at 95 GHz. The reflection coefficient of the novel absorber is 3-4 times lower than that of commercial absorbers with identical geometry. Samples prepared by freeze-drying at -25 degrees C demonstrate resonance behavior, while those prepared at liquid nitrogen temperature (-196 degrees C) exhibit a significant decrease in reflection coefficient, with no resonant behavior. CNT absorbers of identical volume based on wet-phase drying preparation show significantly worse performance than the CNT aerogel absorbers prepared by freeze-drying. Treatment of the freeze-dried CNT aerogel with n- and p-dopants (monoethanolamine and iodine vapors, respectively) shows remarkable improvement in the performance of the waveguide embedded absorbers, reducing the reflection coefficient by 2 dB across the band.

  • 5.
    Ao, Xianyu
    et al.
    South China Normal Univ, South China Acad Adv Optoelect, Ctr Opt & Electromagnet Res, Guangzhou 510006, Guangdong, Peoples R China..
    Xu, Xinan
    South China Normal Univ, South China Acad Adv Optoelect, Ctr Opt & Electromagnet Res, Guangzhou 510006, Guangdong, Peoples R China..
    Dong, Jinwu
    South China Normal Univ, South China Acad Adv Optoelect, Ctr Opt & Electromagnet Res, Guangzhou 510006, Guangdong, Peoples R China..
    He, Sailing
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion. South China Normal Univ, South China Acad Adv Optoelect, Ctr Opt & Electromagnet Res, Guangzhou 510006, Guangdong, Peoples R China.;Zhejiang Univ, Natl Engn Res Ctr Opt Instruments, Ctr Opt & Electromagnet Res, JORCEP, Hangzhou 310058, Zhejiang, Peoples R China..
    Unidirectional Enhanced Emission from 2D Monolayer Suspended by Dielectric Pillar Array2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 41, s. 34817-34821Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Monolayers of transition metal dichalcogenides show great promise for optoelectronic devices as atomically thin semiconductors. Although dielectric or metal nanostructures have been extensively studied for tailoring and enhancing emission from monolayers, their applications are limited because of the mode concentrating inside the dielectric or the high optical losses in metals, together with the low quantum yield in monolayers. Here, we demonstrate that a metal-backed dielectric pillar array can suspend monolayers to increase the radiative recombination, and simultaneously, create strongly confined band-edge modes on surface directly accessible to monolayers. We observe unidirectional enhanced emission from WSe2 monolayers on polymer pillar array.

  • 6.
    Aulin, Christian
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Karabulut, Erdem
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Tran, Amy
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Lindström, Tom
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Transparent Nanocellulosic Multilayer Thin Films on Polylactic Acid with Tunable Gas Barrier Properties2013Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, nr 15, s. 7352-7359Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The layer-by-layer (LbL) deposition method was used for the build-up of alternating layers of nanofibrillated cellulose (NFC) or carboxymethyl cellulose (CMC) with a branched, cationic polyelectrolyte, polyethyleneimine (PEI) on flexible poly (lactic acid) (PLA) substrates. With this procedure, optically transparent nanocellulosic films with tunable gas barrier properties were formed. 50 layer pairs of PEI/NFC and PEI/CMC deposited on PLA have oxygen permeabilities of 0.34 and 0.71 cm(3).mu m/m(2).day.kPa at 23 degrees C and 50% relative humidity, respectively, which is in the same range as polyvinyl alcohol and ethylene vinyl alcohol. The oxygen permeability of these multilayer nanocomposites outperforms those of pure NFC films prepared by solvent-casting. The nanocellulosic LbL assemblies on PLA substrates was in detailed characterized using a quartz crystal microbalance with dissipation (QCM-D). Atomic force microscopy (AFM) reveals large structural differences between the PEI/NFC and the PEI/CMC assemblies, with the PEI/NFC assembly showing a highly entangled network of nanofibrils, whereas the PEI/CMC surfaces lacked structural features. Scanning electron microscopy images showed a nearly perfect uniformity of the nanocellulosic coatings on PLA, and light transmittance results revealed remarkable transparency of the LbL-coated PLA films. The present work demonstrates the first ever LbL films based on high aspect ratio, water-dispersible nanofibrillated cellulose, and water-soluble carboxymethyl cellulose polymers that can be used as multifunctional films and coatings with tailorable properties, such as gas barriers and transparency. Owing to its flexibility, transparency and high-performance gas barrier properties, these thin film assemblies are promising candidates for several large-scale applications, including flexible electronics and renewable packaging.

  • 7. Badea, Adina
    et al.
    McCracken, Joselle M.
    Tillmaand, Emily G.
    Kandel, Mikhail E.
    Oraham, Aaron W.
    Mevis, Molly B.
    Rubakhin, Stanislav S.
    Popescu, Gabriel
    Sweedler, Jonathan V.
    Nuzzo, Ralph G.
    KTH, Skolan för kemivetenskap (CHE).
    3D-Printed pHEMA Materials for Topographical and Biochemical Modulation of Dorsal Root Ganglion Cell Response2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 36, s. 30318-30328Artikkel i tidsskrift (Fagfellevurdert)
  • 8.
    Blomfeldt, Thomas O. J.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Nilsson, Fritjof
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Holgate, Tim
    Xu, Jianxiao
    Johansson, Eva
    Hedenqvist, Mikael S.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Thermal Conductivity and Combustion Properties of Wheat Gluten Foams2012Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 4, nr 3, s. 1629-1635Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Freeze-dried wheat gluten foams were evaluated with respect to their thermal and fire-retardant properties, which are important for insulation applications. The thermal properties were assessed by differential scanning calorimetry, the laser flash method and a hot plate method. The unplasticised foam showed a similar specific heat capacity, a lower thermal diffusivity and a slightly higher thermal conductivity than conventional rigid polystyrene and polyurethane insulation foams. Interestingly, the thermal conductivity was similar to that of closed cell polyethylene and glass-wool insulation materials. Cone calorimetry showed that, compared to a polyurethane foam, both unplasticised and glycerol-plasticised foams had a significantly longer time to ignition, a lower effective heat of combustion and a higher char content. Overall, the unplasticised foam showed better fire-proof properties than the plasticized foam. The UL 94 test revealed that the unplasticised foam did not drip (form droplets of low viscous material) and, although the burning times varied, self-extinguished after flame removal. To conclude both the insulation and fire-retardant properties were very promising for the wheat gluten foam.

  • 9.
    Boujemaoui, Assya
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Carlsson, Linn
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Lahcini, Mohammed
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Sehaqui, Houssine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Facile Preparation Route for Nanostructured Composites: Surface-Initiated Ring-Opening Polymerization of epsilon-Caprolactone from High-Surface-Area Nanopaper2012Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 4, nr 6, s. 3191-3198Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, highly porous nanopaper, i.e., sheets of papers made from non-aggregated nanofibrillated cellulose (NFC), have been surface-grafted with poly(epsilon-caprolactone) (PCL) by surface-initiated ring-opening polymerization (SI-ROP). The nanopaper has exceptionally high surface area (similar to 300 m(2)/g). The "grafting from" of the nanopapers was compared to "grafting from" of cellulose in the form of filter paper, and in both cases either titanium n-butoxide (Ti(On-Bu)(4)) or tin octoate (Sn(Oct)(2)) was utilized as a catalyst. It was found that a high surface area leads to significantly higher amount of grafted PCL in the substrates when Sn(Oct)2 was utilized as a catalyst. Up to 79 wt % PCL was successfully grafted onto the nanopapers as compared to filter paper where only 2-3 wt % PCL was grafted. However, utilizing Ti(On-Bu)4 this effect was not seen and the grafted amount was essentially similar, irrespectively of surface area. The mechanical properties of the grafted nanopaper proved to be superior to those of pure PCL films, especially at elevated temperatures. The present bottom-up preparation route of NFC-based composites allows high NFC content and provides excellent nanostructural control. This is an important advantage compared with some existing preparation routes where dispersion of the filler in the matrix is challenging.

  • 10.
    Boujemaoui, Assya
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Sanchez, Carmen Cobo
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Engström, Joakim
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Bruce, Carl
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Fogelström, Linda
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik. RISE Innventia AB, Stockholm, Sweden.
    Malmström, Eva
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Polycaprolactone Nanocomposites Reinforced with Cellulose Nanocrystals Surface-Modified via Covalent Grafting or Physisorption: A Comparative Study2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 40, s. 35305-35318Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present work, cellulose nanocrystals (CNCs) have been surface-modified either via covalent grafting or through physisorption of poly(n-butyl methacrylate) (PBMA) and employed as reinforcement in PCL. Covalent grafting was achieved by surface-initiated atom transfer radical polymerization (SI-ATRP). Two approaches were utilized for the physisorption: using either micelles of poly(dimethyl aminoethyl methacrylate)-block-poly(n-butyl methacrylate) (PDMAEMA-b-PBMA) or latex nanoparticles of poly(dimethyl aminoethyl methacrylate-co-methacrylic acid)-block-poly(n-butyl methacrylate) (P(DMAEMA-co-MAA)-b-PBMA). Block copolymers (PDMAEMA-b-PBMA)s were obtained by ATRP and subsequently micellized. Latex nanoparticles were produced via reversible addition-fragmentation chain-transfer (RAFT) mediated surfactant-free emulsion polymerization, employing polymer-induced self-assembly (PISA) for the particle formation. For a reliable comparison, the amounts of micelles/latex particles adsorbed and the amount of polymer grafted onto the CNCs were kept similar. Two different chain lengths of PBMA were targeted, below and above the critical molecular weight for chain entanglement of PBMA (M-n,M-c similar to 56 000 g mo1(-1)). Poly(epsilon-caprolactone) (PCL) nanocomposites reinforced with unmodified and modified CNCs in different weight percentages (0.5, 1, and 3 wt %) were prepared via melt extrusion. The resulting composites were evaluated by UV-vis, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and tensile testing. All materials resulted in higher transparency, greater thermal stability, and stronger mechanical properties than unfilled PCL and nanocomposites containing unmodified CNCs. The degradation temperature of PCL reinforced with grafted CNCs was higher than that of micelle-modified CNCs, and the latter was higher than that of latex-adsorbed CNCs with a long PBMA chain length. The results clearly indicate that covalent grafting is superior to physisorption with regard to thermal and mechanical properties of the final nanocomposite. This unique study is of great value for the future design of CNC-based nanocomposites with tailored properties.

  • 11.
    Budnyak, Tetyana
    et al.
    KTH. Natl Acad Sci Ukraine, Chuiko Inst Surface Chem, 17 Gen Naumov St, UA-03164 Kiev, Ukraine..
    Gladysz-Plaska, Agnieszka
    Marie Curie Sklodowska Univ, 2 Marie Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Strizhak, Alexander V.
    Taras Shevchenko Natl Univ Kyiv, 64-13 Volodymyrska St, UA-01601 Kiev, Ukraine..
    Sternik, Dariusz
    Marie Curie Sklodowska Univ, 2 Marie Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Komarov, Igor V.
    Taras Shevchenko Natl Univ Kyiv, 64-13 Volodymyrska St, UA-01601 Kiev, Ukraine..
    Majdan, Marek
    Marie Curie Sklodowska Univ, 2 Marie Curie Sklodowska Sq, PL-20031 Lublin, Poland..
    Tertykh, Valentin A.
    Natl Acad Sci Ukraine, Chuiko Inst Surface Chem, 17 Gen Naumov St, UA-03164 Kiev, Ukraine..
    Imidazole-2yl-Phosphonic Acid Derivative Grafted onto Mesoporous Silica Surface as a Novel Highly Effective Sorbent for Uranium(VI) Ion Extraction2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 7, s. 6681-6693Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new imidazol-2yl-phosphonic acid/mesoporous silica sorbent (ImP(O)(OH)(2)/SiO2) was developed and applied for uranium(VI) ion removal from aqueous solutions. The synthesized material was characterized by fast kinetics and an extra-high adsorption capacity with respect to uranium. The highest adsorption efficiency of U(VI) ions was obtained for the reaction system at pH 4 and exceeded 618 mg/g. The uranium(VI) sorption proceeds quickly in the first step within 60 min of the adsorbent sites and ion interactions. Moreover, the equilibrium time was determined to be 120 min. The equilibrium and kinetic characteristics of the uranium(VI) ions uptake by synthesized sorbent was found to follow the Langmuir-Freundlich isotherm model and pseudo-second-order kinetics rather than the Langmuir, Dubinin-Radushkevich, and Temkin models and pseudo-first-order or intraparticle diffusion sorption kinetics. The adsorption mechanism for uranium on the sorbent was clarified basing on the X-ray photoelectron spectroscopy (XPS) analysis. The model of UO22+ binding to surface of the sorbent was proposed according to the results of XPS, i.e., a 1:1 U-to-P ratio in the sorbed complex was established. The regeneration study confirms the ImP(O)(OH)(2)/SiO2 sorbent can be reused. A total of 45% of uranium ions was determined as originating from the sorbent leaching in the acidic solutions, whereas when the basic solutions were used, the removal efficiency was 12%.

  • 12. Cappel, Ute B
    et al.
    Svanström, Sebastian
    Lanzilotto, Valeria
    Johansson, Fredrik O L
    Aitola, Kerttu
    Philippe, Bertrand
    Giangrisostomi, Erika
    Ovsyannikov, Ruslan
    Leitner, Torsten
    Föhlisch, Alexander
    Svensson, Svante
    Mårtensson, Nils
    Boschloo, Gerrit
    Lindblad, Andreas
    Rensmo, Håkan
    Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells.2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 40, s. 34970-34978Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    ) with the element specificity and chemical sensitivity of core-level photoelectron spectroscopy. By carrying out measurements at a synchrotron beamline optimized for low X-ray fluxes, we are able to avoid sample changes due to X-ray illumination and are therefore able to monitor what sample changes are induced by visible illumination only. We find that laser illumination causes partially reversible chemistry in the surface region, including enrichment of bromide at the surface, which could be related to a phase separation into bromide- and iodide-rich phases. We also observe a partially reversible formation of metallic lead in the perovskite structure. These processes occur on the time scale of minutes during illumination. The presented methodology has a large potential for understanding light-induced chemistry in photoactive materials and could specifically be extended to systematically study the impact of morphology and composition on the photostability of metal halide perovskites.

  • 13.
    Carosio, Federico
    et al.
    Politecn Torino, I-15121 Alessandria, Italy.
    Kochumalayil, Jose
    Cuttica, F.
    Camino, G.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Biokompositer.
    Oriented Clay Nanopaper from Biobased Components Mechanisms for Superior Fire Protection Properties2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 10, s. 5847-5856Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The toxicity of the most efficient fire retardant additives is a major problem for polymeric Materials. Cellulose nanofiber (CNF)/clay nanocomposites, with unique brick-and-mortar structure and prepared by simple filtration, are characterized from the morphological point of view by scanning electron microscopy and X-ray diffraction. These nanocomposites have superior fire protection properties to Other clay nanocomposites and fiber composites. The Corresponding mechanisms are evaluated in terms of flammability (reaction to a flame) and cone calorimetry (exposure to heat flux). These two tests provide a wide spectrum characterization of fire protection properties in CNF/montmorrilonite (MTM) Materials. The morphology of the collected residues after flammability testing is investigated. In addition, thermal and thermo-oxidative stability are evaluated by thermogravimetric analyses performed in inert (nitrogen) and oxidative (air) atmospheres. Physical and chemical mechanisms are identified and related to the unique nanostructure and its low thermal conductivity, high gas barrier properties and CNF/ MTM interactions for char formation.

  • 14.
    Carrick, Christopher
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi.
    Pendergraph, Samuel A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Fiberteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Nanometer Smooth, Macroscopic Spherical Cellulose Probes for Contact Adhesion Measurements2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 23, s. 20928-20935Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cellulose spheres were prepared by dissolving cellulose fibers and subsequently solidifying the solution in a nonsolvent. Three different solution concentrations were tested and several nonsolvents were evaluated for their effect on the formation of spheres. Conditions were highlighted to create cellulose spheres with a diameter of similar to 1 mm and a root-mean-square surface roughness of similar to 1 nm. These solid spheres were shown to be easily chemically modified without changing the mechanical properties significantly. Contact adhesion measurements were then implemented with these spheres against a poly(dimethylsiloxane) (PDMS) elastomer in order to quantify the adhesion. Using Johnson-Kendall-Roberts (JKR) theory, we quantified the adhesion for unmodified cellulose and hydrophobic cellulose spheres. We highlight the ability of these spheres to report more accurate adhesion information, compared to spin-coated thin films. The application of these new cellulose probes also opens up new possibilities for direct, accurate measurement of adhesion between cellulose and other materials instead of using uncertain surface energy determinations to calculate the theoretical work of adhesion between cellulose and different solid materials.

  • 15.
    Cervin, Nicholas Tchang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Fiberteknologi.
    Johanson, Erik
    Larsson, Per A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Strong, Water-Durable, and Wet-Resilient Cellulose Nanofibril-Stabilized Foams from Oven Drying2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 18, s. 11682-11689Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Porous materials from cellulose nanofibrils (CNFs) have been prepared using Pickering foams from aqueous dispersions. Stable wet foams were first produced using surface-modified CNFs as stabilizing particles. To better maintain the homogeneous pore structure of the foam after drying, the foams were dried in an oven on a liquid-filled porous ceramic frit. The cell structure was studied by scanning electron microscopy and liquid porosimetry, the mechanical properties were studied by compression testing, and the liquid absorption capacity was determined both with liquid porosimetry and by soaking in water. By controlling the charge density of the CNFs, it was possible to prepare dry foams with different densities, the lowest density being 6 kg m(-3), that is, a porosity of 99.6%. For a foam with a density of 200 kg m(-3) the compressive Young's modulus was 50 MPa and the energy absorption to 70% strain was 2.3 MJ M-3. The use of chemically modified CNFs made it possible to prepare cross-linked foams with water-durable and wet-resilient properties. These foams absorbed liquid up to 34 times their own weight and were able to release this liquid under compression and to reabsorb the same amount when the pressure was released.

  • 16.
    Chen, Cheng
    et al.
    Jiangsu Univ, Inst Energy Res, Zhenjiang 212013, Peoples R China..
    Li, Hongping
    Jiangsu Univ, Inst Energy Res, Zhenjiang 212013, Peoples R China..
    Ding, Xingdong
    Jiangsu Univ, Inst Energy Res, Zhenjiang 212013, Peoples R China..
    Cheng, Ming
    Jiangsu Univ, Inst Energy Res, Zhenjiang 212013, Peoples R China..
    Li, Henan
    Jiangsu Univ, Sch Chem & Chem Engn, Zhenjiang 212013, Peoples R China..
    Xu, Li
    Jiangsu Univ, Inst Energy Res, Zhenjiang 212013, Peoples R China..
    Qiao, Fen
    Jiangsu Univ, Sch Energy & Power Engn, Zhenjiang 212013, Peoples R China..
    Li, Huaming
    Jiangsu Univ, Inst Energy Res, Zhenjiang 212013, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Molecular Engineering of Triphenylamine-Based Non-Fullerene Electron-Transport Materials for Efficient Rigid and Flexible Perovskite Solar Cells2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 45, s. 38970-38977Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There has been a growing interest in the design and synthesis of non-fullerene electron transport materials (ETMs) for perovskite solar cells (PSCs), which may overcome the drawbacks of traditional fullerene derivatives. In this work, a novel donor-acceptor (D-A) structured ETM termed TPA-3CN is presented by molecular engineering of triphenylamine (TPA) as the donor group and (3-cyano-4,5,5-trimethyl-2(5H)-furanylidene) malononitrile as the acceptor group. To further improve the electron mobility and conductivity and achieve excellent photovoltaic performance, a solution processable n-type dopant is introduced during the ETM spin-coating step. After device optimization, PSCs based on the doped TPA-3CN exhibit an impressive power conversion efficiency (PCE) of 19.2% with a negligible hysteresis. Benefitting from the low temperature and good solution processability of ETM TPA-3CN, it was further applied in flexible inverted PSCs and an impressive PCE of 13.2% was achieved, which is among the highest values reported for inverted flexible fullerene-free PSCs.

  • 17. Chen, Cheng
    et al.
    Yang, Xichuan
    Cheng, Ming
    Zhang, Fuguo
    Zhao, Jianghua
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Efficient Panchromatic Organic Sensitizers with Dihydrothiazole Derivative as pi-Bridge for Dye-Sensitized Solar Cells2013Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 5, nr 21, s. 10960-10965Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Novel organic dyes CC201 and CC202 with dihydrothiazole derivative as pi-bridge have been synthesizedand applied in the DSSCs. With the synergy electron-withdrawing of dihydrothiazole and cyanoacrylic acid, these two novel dyes CC201 and CC202 show excellent response in the region of 500-800 nm. An efficiency as high as 6.1% was obtained for the device fabricated by sensitizer CC202 together with cobalt electrolyte under standard light illumination (AM 1.5G, 100 mW cm(-2)). These two novel D-pi-A panchromatic organic dyes gave relatively high efficiencies except common reported squaraine dyes.

  • 18. Chen, Song
    et al.
    Liu, Peng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Hua, Yong
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Li, Yuanyuan
    Kloo, Lars
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Wang, Xingzhu
    Ong, Beng
    Wong, Wai-Kwok
    Zhu, Xunjin
    Study of Arylamine-Substituted Porphyrins as Hole-Transporting Materials in High-Performance Perovskite Solar Cells2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 15, s. 13231-13239Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To develop new hole-transporting materials (HTMs) for efficient and stable perovskite solar. cells (PSCs), 5,10,15,20-tetrakis{4-[N,N-di(4-thethoxylphenyl)amino-phenyl]}-porphyrin was prepared in gram scale through the direct condensation of pyrrole and 4-[bis(4-methoxyphenyl)amino]-benzaldehyde. Its Zn(II) and Cu(II) complexes exhibit excellent thermal and electrochemical stability, specifically a high hole Mobility and very favorable energetics for hole extraction that render them a new class of HTMs in organometallic halide PSCs. As expected, ZnP as HTM in PSCs affords a competitive power conversion efficiency (PCE) of 17.78%,which is comparable to that of the most powerful HTM of Spiro-MeOTAD (18.59%) under the same working conditions. Mean-While, the metal centers affect somewhat the photovoltaic performances that CuP as HTM produces a lower PCE of 15.36%. Notably, the PSCs employing ZnP show a much,better stability than Spiro-OMeTAD. Moreover, the two-porphyrin-based HTMs can be prepared from relatively cheap raw materials with a facile synthetic route. The results demonstrate that ZnP and CuP can be a new class of HTMs for efficient and stable PSCs. To the best of our knowledge, this is the best performance that porphyrin-based solar cells could show with PCE > 17%.

  • 19. Chen, Zhe
    et al.
    Lu, Jinfeng
    Ai, Yuejie
    Ji, Yongfei
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Adschiri, Tadafumi
    Wan, Lijun
    Ruthenium/Graphene-like Layered Carbon Composite as an Efficient Hydrogen Evolution Reaction Electrocatalyst2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 51, s. 35132-35137Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Efficient water splitting through electrocatalysis has been studied extensively in modern energy devices, while the development of catalysts with activity and stability comparable to those of Pt is still a great challenge. In this work, we successfully developed a facile route to synthesize graphene-like layered carbon (GLC) from a layered silicate template. The obtained GLC has layered structure similar to that of the template and can be used as support to load ultrasmall Ru nanoparticles on it in supercritical water. The specific structure and surface properties of GLC enable Ru nanoparticles to disperse highly uniformly on it even at a large loading amount (62 wt %). When the novel Ru/GLC was used as catalyst on a glass carbon electrode for hydrogen evolution reaction (HER) in a 0.5 M H2SO4 solution, it exhibits an extremely low onset potential of only 3 mV and a small Tafel slope of 46 mV/decade. The outstanding performance proved that Ru/GLC is highly active catalyst for HER, comparable with transition-metal dichalcogenides or selenides. As the price of ruthenium is much lower than platinum, our study shows that Ru/GLC might be a promising candidate as an HER catalyst in future energy applications.

  • 20. Chernyy, Sergey
    et al.
    Järn, Mikael
    Shimizu, Kyoko
    Swerin, Agne
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Pedersen, Steen Uttrup
    Daasbjerg, Kim
    Makkonen, Lasse
    Claesson, Per
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Iruthayaraj, Joseph
    Superhydrophilic Polyelectrolyte Brush Layers with Imparted Anti-Icing Properties: Effect of Counter ions2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 9, s. 6487-6496Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed by polymerization via the SI-ATRP route. The cationic [2-(methacryloyloxy)ethyl]trimethylammonium chloride] and the anionic [poly(3-sulfopropyl methacrylate), poly(sodium methacrylate)] polyelectrolyte brushes were further exchanged with H+, Li+, Na+, K+, Ag+, Ca2+, La3+, C16N+, F-, Cl-, BF4-, SO42-, and C12SO3- ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li+ ions reduce ice adhesion by 40% at 18 degrees C and 70% at 10 degrees C. Ag+ ions reduce ice adhesion by 80% at -10 degrees C relative to unmodified glass. In general, superhydrophilic polyelectrolyte brushes exhibit better anti-icing property at -10 degrees C compared to partially hydrophobic brushes such as poly(methyl methacrylate) and surfactant exchanged polyelectrolyte brushes. The data are interpreted using the concept of a quasi liquid layer (QLL) that is enhanced in the presence of highly hydrated ions at the interface. It is suggested that the ability of ions to coordinate water is directly related to the efficiency of a given anti-icing coating based on the polyelectrolyte brush concept.

  • 21.
    Choi, Hyungryul J.
    et al.
    MIT, Dept Mech Engn, Cambridge, MA 02139 USA.;1 Infinite Loop, Cupertino, CA 95014 USA..
    Park, Kyoo-Chul
    MIT, Dept Mech Engn, Cambridge, MA 02139 USA.;Northwestern Univ, Dept Mech Engn, Evanston, IL 60208 USA..
    Lee, Hyomin
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA.;Harvard Univ, John A Paulson Sch Engn & Appl Sci, Cambridge, MA 02138 USA..
    Crouzier, Thomas
    KTH, Skolan för bioteknologi (BIO). MIT, Dept Biol Engn, 77 Massachusetts Ave, Cambridge, MA 02139 US.
    Rubner, Michael F.
    MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA..
    Cohen, Robert E.
    MIT, Dept Chem Engn, Cambridge, MA 02139 USA..
    Barbastathis, George
    MIT, Dept Mech Engn, Cambridge, MA 02139 USA.;Singapore MIT Alliance Res & Technol SMART Ctr, Singapore, Singapore..
    McKinley, Gareth H.
    MIT, Dept Mech Engn, Cambridge, MA 02139 USA..
    Superoleophilic Titania Nanoparticle Coatings with Fast Fingerprint Decomposition and High Transparency2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 9, s. 8354-8360Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low surface tension sebaceous liquids such as human fingerprint oils are readily deposited on high energy surfaces such as clean glass, leaving smudges that significantly lower transparency. There have been several attempts to prevent formation of these dactylograms on glass by employing oil-repellent textured surfaces. However, nanotextured superoleophobic coatings typically scatter visible light, and the intrinsic thermodynamic metastability of the composite superoleophobic state can result in failure of the oil repellency under moderate contact pressure. We develop titania-based porous nanoparticle coatings that are superoleophilic and highly transparent and which exhibit short time scales for decomposition of fingerprint oils under ultraviolet light. The mechanism by which a typical dactylogram is consumed combines wicking of the sebum into the nanoporous titania structure followed by photocatalytic degradation. We envision a wide range of applications because these TiO2 nanostructured surfaces remain photocatalytically active against fingerprint oils in natural sunlight and are also compatible with flexible glass substrates.

  • 22. Chouhan, Dimple
    et al.
    Thatikonda, Naresh
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinteknologi.
    Nilebäck, Linnea
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Widhe, Mona
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinteknologi.
    Hedhammar, My
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinteknologi.
    Mandal, Biman B.
    Recombinant Spider Silk Functionalized Silkworm Silk Matrices as Potential Bioactive Wound Dressings and Skin Grafts2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 28, s. 23560-23572Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Silk is considered to be a potential biomaterial for a wide number of biomedical applications. Silk fibroin (SF) can be retrieved in sufficient quantities from the cocoons produced by silkworms. While it is easy to formulate into scaffolds with favorable mechanical properties, the natural SF does not contain bioactive functions. Spider silk proteins, on the contrary, can be produced in fusion with bioactive protein domains, but the recombinant procedures are expensive, and large-scale production is challenging. We combine the two types of silk to fabricate affordable, functional tissue-engineered constructs for wound-healing applications. Nanofibrous mats and microporous scaffolds made of natural silkworm SF are used as a bulk material that are top-coated with the recombinant spider silk protein (4RepCT) in fusion with a cell-binding motif, antimicrobial peptides, and a growth factor. For this, the inherent silk properties are utilized to form interactions between the two silk types by self-assembly. The intended function, that is, improved cell adhesion, antimicrobial activity, and growth factor stimulation, could be demonstrated for the obtained functionalized silk mats. As a skin prototype, SF scaffolds coated with functionalized silk are cocultured with multiple cell types to demonstrate formation of a bilayered tissue construct with a keratinized epidermal layer under in vitro conditions. The encouraging results support this strategy of fabrication of an affordable bioactive SF-spider silk-based biomaterial for wound dressings and skin substitutes.

  • 23. D'Amario, Luca
    et al.
    Jiang, Roger
    Cappel, Ute B.
    Gibson, Elizabeth A.
    Boschloo, Gerrit
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Rensmo, Hakan
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Hammarstrom, Leif
    Tian, Haining
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Chemical and Physical Reduction of High Valence Ni States in Mesoporous NiO Film for Solar Cell Application2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 39, s. 33470-33477Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The most common material for dye-sensitized photocathodes is mesoporous NiO. We transformed the usual brownish NiO to be more transparent by reducing high valence Ni impurities. Two pretreatment methods have been used: chemical reduction by NaBH4 and thermal reduction by heating. The power conversion efficiency of the cell was increased by 33% through chemical treatment, and an increase in open-circuit voltage from 105 to 225 mV was obtained upon heat treatment. By optical spectroelectrochemistry, we could identify two species with characteristically different spectra assigned to Ni3+ and Ni4+. We suggest that the reduction of surface Ni3+ and Ni (4+) to Ni (2+) decreases the recombination reaction between holes on the NiO surface with the electrolyte. It also keeps the dye firmly on the surface, building a barrier for electrolyte recombination. This causes an increase in open-circuit photovoltage for the treated film.

  • 24. Damasco, Jossana A.
    et al.
    Chen, Guanying
    Shao, Wei
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Huang, Haoyuan
    Song, Wentao
    Lovell, Jonathan F.
    Prasad, Paras N.
    Size-Tunable and Monodisperse Tm3+/Gd3+-Doped Hexagonal NaYbF4 Nanoparticles with Engineered Efficient Near Infrared-to-Near Infrared Upconversion for In Vivo Imaging2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 16, s. 13884-13893Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hexagonal NaYbF4:Tm3+ upconversion nanoparticles hold promise for use in high contrast near-infrared-to-near-infrared (NIR-to-NIR) in vitro and in vivo bioirnaging. However, significant hurdles remain in their preparation and control of their morphology and size, as well as in enhancement of their upconversion efficiency. Here, we describe a systematic approach to produce highly controlled hexagonal NaYbF4:Tm3+ nanopartides with superior upconversion. We found that doping appropriate concentrations of trivalent gadolinium (Gd3+) can convert NaYbF4:Tm3+ 0.5% nanopartides with cubic phase and irregular shape into highly monodisperse NaYbF4:Tm3+ 0.5% nanoplates or nanospheres in a pure hexagonal-phase and of tunable size. The intensity and the lifetime of the upconverted NIR luminescence at 800 nm exhibit a direct dependence on the size distribution of the resulting nanopartides, being ascribed to the varied surface-to-volume ratios determined by the different nanoparticle size. Epitaxial growth of a thin NaYF4 shell layer of similar to 2 nm on the similar to 22 nm core of hexagonal NaYbF4:Gd3+ 30%/Tm3+ 0.5% nanoparticles resulted in a dramatic 350 fold NIR upconversion efficiency enhancement, because of effective suppression of surface-related quenching mechanisms. In vivo NIR-to-NIR upconversion imaging was demonstrated using a dispersion of phospholipid-polyethylene glycol (DSPE-PEG)-coated core/shell nanopartides in phosphate buffered saline.

  • 25. de Francisco, Raquel
    et al.
    Tiemblo, Pilar
    Hoyos, Mario
    Gonzalez-Arellano, Camino
    Garcia, Nuria
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Synytska, Alla
    Multipurpose Ultra and Superhydrophobic Surfaces Based on Oligodimethylsiloxane-Modified Nanosilica2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 21, s. 18998-19010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nonfluorinated hydrophobic surfaces are of interest for reduced cost, toxicity, and environmental problems. Searching for such surfaces together with versatile processing, A200 silica nanoparticles are modified with an oligodimethylsiloxane and used by themselves or with a polymer matrix. The goal of the surface modification is controlled aggregate size and stable suspensions. Characterization is done by NMR, microanalysis, nitrogen adsorption, and dynamic light scattering. The feasibility of the concept is then demonstrated. The silica aggregates are sprayed in a scalable process to form ultrahydrophobic and imperceptible coatings with surface topographies of controlled nanoscale roughness onto different supports, including nanofibrillated cellulose. To improve adhesion and wear properties, the organosilica was mixed with polymers. The resulting composite coatings are characterized by FE-SEM, AFM, and contact angle measurements. Depending on the nature of the polymer, different functionalities can be developed. Poly(methyl methacrylate) leads to almost superhydrophobic and highly transparent coatings. Composites based on commercial acrylic car paint show "pearl-bouncing" droplet behavior. A light-emitting polyfluorene is synthesized to prepare luminescent and water repellent coatings on different supports. The interactions between polymers and the organosilica influence coating roughness and are critical for wetting behavior. In summary, the feasibility of a facile, rapid, and fluorine-free hydrophobization concept was successfully demonstrated in multipurpose antiwetting applications.

  • 26. de Oliveira, R.
    et al.
    Sjödin, N.
    Fokine, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    Margulis, Walter
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Laserfysik.
    de Matos, C.
    Norin, L.
    Fabrication and Optical Characterization of Silica Optical Fibers Containing Gold Nanoparticles2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 1, s. 370-375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gold nanoparticles have been used since antiquity for the production of red-colored glasses. More recently, it was determined that this color is caused by plasmon resonance, which additionally increases the material's nonlinear optical response, allowing for the improvement of numerous optical devices. Interest in silica fibers containing gold nanoparticles has increased recently, aiming at the integration of nonlinear devices with conventional optical fibers. However, fabrication is challenging due to the high temperatures required for silica processing and fibers with gold nanoparticles were solely demonstrated using sol-gel techniques. We show a new fabrication technique based on standard preform/fiber fabrication methods, where nanoparticles are nucleated by heat in a furnace or by laser exposure with unprecedented control over particle size, concentration, and distribution. Plasmon absorption peaks exceeding 800 dB m(-1) at 514-536 nm wavelengths were observed, indicating higher achievable nanoparticle concentrations than previously reported. The measured resonant nonlinear refractive index, (6.75 ± 0.55) × 10(-15) m(2) W(-1), represents an improvement of >50×.

  • 27. Decrop, Deborah
    et al.
    Pardon, Gaspard
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Brancato, Luigi
    Kil, Dries
    Zandi Shafagh, Reza
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Kokalj, Tadej
    Haraldsson, Klas Tommy
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Puers, Robert
    van der Wijngaart, Wouter
    KTH, Skolan för elektro- och systemteknik (EES), Mikro- och nanosystemteknik.
    Lammertyn, Jeroen
    Single-step imprinting of femtoliter microwell arrays allows digital bioassays with attomolar limit of detection2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bead-based microwell array technology is growing as an ultrasensitive target detection tool. However, dissemination of the technology and its commercial use are hampered by current fabrication methods for hydrophilic-in-hydrophobic microwell arrays, which are either expensive or labour-intensive to manufacture, or which results in low bead seeding efficiencies. In this paper, we present a novel single-step manufacturing method for imprinting cheap and disposable hydrophilic-in-hydrophobic microwell arrays suitable for single-molecule detection. Single-step imprinting of hydrophilic-in-hydrophobic microwell arrays is made possible using an innovative surface energy replication approach by means of a hydrophobic thiol-ene polymer formulation. In this polymer, hydrophobic-moiety-containing monomers self-assemble against the hydrophobic surface of the imprinting stamp, which results in a hydrophobic replica surface after polymerization. After removing the stamp, hydrophilic wells are obtained with the well bottoms consisting of glass substrate. We demonstrate that the hydrophilic-in-hydrophobic imprinted microwell arrays enable successful and efficient self-assembly of individual water droplets and seeding of magnetic beads with loading efficiencies up to 96%. We also demonstrate the suitability of the microwell arrays for the isolation and detection of single-molecules achieving a limit of detection of 17.4 aM when performing a streptavidin-biotin binding assay. The ease of manufacturing demonstrated here is expected to allow translation of digital microwell array technology towards diagnostic applications.

  • 28.
    Eita, Mohamed
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Wagberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Spin-Assisted Multilayers of Poly(methyl methacrylate) and Zinc Oxide Quantum Dots for Ultraviolet-Blocking Applications2012Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 4, nr 6, s. 2920-2925Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thin UV-blocking films of poly(methyl methacrylate) (PMMA) and ZnO quantum dots (QDs) were built-up by spin-coating. Ellipsometry reveals average thicknesses of 9.5 and 8.6 nm per bilayer before and after heating at 100 degrees C for one hour, respectively. The surface roughness measured by Atomic force microscopy (AFM) was 3.6 and 8.4 nm for the one and ten bilayer films, respectively. The linear increase in thickness as well as the low surface roughness increment per bilayer indicates a stratified multilayer structure and a smooth interface without: aggregation. The absorption of UV radiation increased with increasing number of bilayers. At the same time, transmission was damped at wavelengths shorter than 375 nm. The thin films had a high and constant transparency in the visible region. Green-light emitting QDs could be detected by confocal microscopy at a concentration of 20% in a single layer of PMMA/ZnO. PMMA/ZnO QDs thin films are hydrophobic, as indicated by contact angle measurements.

  • 29.
    Enrico, Alessandro
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Dubois, Valentin J.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Niklaus, Frank
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Stemme, Göran
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Mikro- och nanosystemteknik.
    Scalable Manufacturing of Single Nanowire Devices Using Crack-Defined Shadow Mask Lithography2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single nanowires (NWs) have a broad range of applications in nanoelectronics, nanomechanics, and nano photonics, but, to date, no technique can produce single sub 20 nm wide NWs with electrical connections in a scalable fashion. In this work, we combine conventional optical and crack lithographies to generate single NW devices with controllable and predictable dimensions and placement and with individual electrical contacts to the NWs. We demonstrate NWs made of gold, platinum, palladium, tungsten, tin, and metal oxides. We have used conventional i-line stepper lithography with a nominal resolution of 365 nm to define crack lithography structures in a shadow mask for large-scale manufacturing of sub-20 nm wide NWs, which is a 20-fold improvement over the resolution that is possible with the utilized stepper lithography. Overall, the proposed method represents an effective approach to generate single NW devices with useful applications in electrochemistry, photonics, and gas- and biosensing.

  • 30.
    Fernandes, Susana C. M.
    et al.
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. University of the Basque Country, Spain.
    Alonso-Varona, Ana
    Palomares, Teodoro
    Zubillaga, Veronica
    Labidi, Jalel
    Bulone, Vincent
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap. University of Adelaide, Australia.
    Exploiting Mycosporines as Natural Molecular Sunscreens for the Fabrication of UV-Absorbing Green Materials2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 30, s. 16558-16564Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultraviolet radiations have many detrimental effects in living organisms that challenge the stability and function of cellular structures. UV exposure also alters the properties and durability of materials and affects their lifetime. It is becoming increasingly important to develop new biocompatible and environmentally friendly materials to address these issues. Inspired by the strategy developed by fish, algae, and microorganisms exposed to UV radiations in confined ecosystems, we have constructed novel UV-protective materials that exclusively consist of natural compounds. Chitosan was chosen as the matrix for grafting mycosporines and mycosporine-like amino acids as the functional components of the active materials. Here, we show that these materials are biocompatible, photoresistant, and thermoresistant, and exhibit a highly efficient absorption of both UV-A and UV-B radiations. Thus, they have the potential to provide an efficient protection against both types of UV radiations and overcome several shortfalls of the current UV-protective products. In practice, the same concept can be applied to other biopolymers than chitosan and used to produce multifunctional materials. Therefore, it has a great potential to be exploited in a broad range of applications in living organisms and nonliving systems.

  • 31.
    Friis, Jakob Ege
    et al.
    Aarhus Univ, Dept Biol & Chem Engn, Hangovej 2, DK-8200 Aarhus N, Denmark..
    Brons, Kaare
    Aarhus Univ, Dept Biol & Chem Engn, Hangovej 2, DK-8200 Aarhus N, Denmark..
    Salmi, Zakaria
    Aarhus Univ, Dept Chem, Langelandsgade 140, DK-8000 Aarhus C, Denmark..
    Shimizu, Kyoko
    SACHEM Japan GK, 5-6-27 Mizuhai, Higashiosaka, Osaka 5780921, Japan..
    Subbiahdoss, Guruprakash
    Aarhus Univ, Interdisciplinary Nanosci Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark..
    Holm, Allan Hjarbaek
    Grundfos Holding AS, Poul Due Jensens Vej 7, DK-8850 Bjerringbro, Denmark..
    Santos, Olga
    Alfa Laval Lund AB, Mat & Chem Ctr, POB 74, SE-22100 Lund, Sweden..
    Pedersen, Steen Uttrup
    Aarhus Univ, Dept Chem, Langelandsgade 140, DK-8000 Aarhus C, Denmark.;Aarhus Univ, Interdisciplinary Nanosci Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark..
    Meyer, Rikke Louise
    Aarhus Univ, Dept Biosci, Ny Munkegade 116, DK-8000 Aarhus C, Denmark.;Aarhus Univ, Interdisciplinary Nanosci Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark..
    Daasbjerg, Kim
    KTH. Aarhus Univ, Dept Chem, Langelandsgade 140, DK-8000 Aarhus C, Denmark.;Aarhus Univ, Interdisciplinary Nanosci Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.;KTH Royal Inst Technol, Appl Phys Chem, SE-10044 Stockholm, Sweden.;Carbon Dioxide Activat Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark..
    Iruthayaraj, Joseph
    Aarhus Univ, Dept Biol & Chem Engn, Hangovej 2, DK-8200 Aarhus N, Denmark.;Aarhus Univ, Interdisciplinary Nanosci Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark.;Carbon Dioxide Activat Ctr, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark..
    Hydrophilic Polymer Brush Layers on Stainless Steel Using Multilayered ATRP Initiator Layer2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 44, s. 30616-30627Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thin polymer coatings (in tens of nanometers to a micron thick) are desired on industrial surfaces such as stainless steel. In this thickness range coatings are difficult to produce using conventional methods. In this context, surface-initiated controlled polymerization method can offer a promising tool to produce thin polymer coatings via bottom-up approach. Furthermore, the industrial surfaces are chemically heterogeneous and exhibit surface features in the form of grain boundaries and grain surfaces. Therefore, the thin coatings must be equally effective on both the grain surfaces and the grain boundary regions. This study illustrates a novel "periodic rejuvenation of surface initiation" process using surface-initiated ATRP technique to amplify the graft density of poly(oligoethylene glycol)methacrylate (POEGMA) brush layers on stainless steel 316L surface. The optimized conditions demonstrate a controlled, macroscopically homogeneous, and stable POEGMA brush layer covering both the grain surface and the grain boundary region. Various relevant parameters-surface cleaning methods, controllability of thickness, graft density, homogeneity and stability-were studied using techniques such as ellipsometer, X-ray photoelectron spectroscopy, scanning electron microscopy-energy-dispersive X-ray, surface zeta potential, and infrared reflection-adsorption spectroscopy.

  • 32.
    Fu, Qiliang
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Medina, Lilian
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Li, Yuanyuan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Carosio, Federico
    Hajian, Alireza
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Berglund, Lars A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Nanostructured Wood Hybrids for Fire-Retardancy Prepared by Clay Impregnation into the Cell Wall2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 41, s. 36154-36163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eco-friendly materials need "green" fire-retardancy treatments, which offer opportunity for new wood nanotechnologies. Balsa wood (Ochroma pyramidale) was delignified to form a hierarchically structured and nanoporous scaffold mainly composed of cellulose nanofibrils. This nanocellulosic wood scaffold was impregnated with colloidal montmorillonite clay to form a nanostructured wood hybrid with high flame-retardancy. The nanoporous scaffold was characterized by scanning electron microscopy and gas adsorption. Flame-retardancy was evaluated by cone calorimetry, whereas thermal and thermo-oxidative stabilities were assessed by thermogravimetry. The location of well-distributed clay nanoplatelets inside the cell walls was confirmed by energy-dispersive X-ray analysis. This unique nanostructure dramatically increased the thermal stability because of thermal insulation, oxygen depletion, and catalytic charring effects. A coherent organic/inorganic charred residue was formed during combustion, leading to a strongly reduced heat release rate peak and reduced smoke generation.

  • 33.
    Galland, Sylvain
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Andersson, Richard L.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Ström, Valter
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Teknisk materialfysik.
    Olsson, Richard
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymera material.
    Berglund, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Biokompositer.
    Strong and Moldable Cellulose Magnets with High Ferrite Nanoparticle Content2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 22, s. 20524-20534Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A major limitation in the development of highly functional hybrid nanocomposites is brittleness and low tensile strength at high inorganic nanoparticle content. Herein, cellulose nanofibers were extracted from wood and individually decorated with cobalt-ferrite nanoparticles and then for the first time molded at low temperature (<120 degrees C) into magnetic nanocomposites with up to 93 wt % inorganic content. The material structure was characterized by TEM and FE-SEM and mechanically tested as compression molded samples. The obtained porous magnetic sheets were further impregnated with a thermosetting epoxy resin, which improved the load-bearing functions of ferrite and cellulose material. A nanocomposite with 70 wt % ferrite, 20 wt % cellulose nanofibers, and 10 wt % epoxy showed a modulus of 12.6 GPa, a tensile strength of 97 MPa, and a strain at failure of ca. 4%. Magnetic characterization was performed in a vibrating sample magnetometer, which showed that the coercivity was unaffected and that the saturation magnetization was in proportion with the ferrite content. The used ferrite, CoFe2O4 is a magnetically hard material, demonstrated by that the composite material behaved as a traditional permanent magnet. The presented processing route is easily adaptable to prepare millimeter-thick and moldable magnetic objects. This suggests that the processing method has the potential to be scaled-up for industrial use for the preparation of a new subcategory of magnetic, low-cost, and moldable objects based on cellulose nanofibers.

  • 34.
    Gao, Jiajia
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    El-Zohry, Ahmed M.
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 523, SE-75120 Uppsala, Sweden..
    Trilaksana, Herri
    Flinders Univ S Australia, Flinders Ctr NanoScale Sci & Technol CNST, Adelaide, SA 5042, Australia..
    Gabrielsson, Erik
    Dyenamo AB, Greenhouse Labs, Tekn Ringen 38A, SE-11428 Stockholm, Sweden..
    Leandri, Valentina
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Ellis, Hanna
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 523, SE-75120 Uppsala, Sweden..
    D'Amario, Luca
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 523, SE-75120 Uppsala, Sweden..
    Safdari, Majid
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Gardner, James M.
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Andersson, Gunther
    Flinders Univ S Australia, Flinders Ctr NanoScale Sci & Technol CNST, Adelaide, SA 5042, Australia..
    Kloo, Lars
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Light-Induced Interfacial Dynamics Dramatically Improve the Photocurrent in Dye-Sensitized Solar Cells: An Electrolyte Effect2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 31, s. 26241-26247Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A significant increase in the photocurrent generation during light soaking for solar cells sensitized by the triphenylamine-based D-pi-A organic dyes (PD2 and LEG1) and mediated by cobalt bipyridine redox complexes has been observed and investigated. The crucial role of the electrolyte has been identified in the performance improvement. Control experiments based on a pretreatment strategy reveals TBP as the origin. The increase in the current and IPCE has been interpreted by the interfacial charge-transfer kinetics studies. A slow component in the injection kinetics was exposed for this system. This change explains the increase in the electron lifetime and collection efficiency. Photoelectron spectroscopic measurements show energy shifts at the dye/TiO2 interface, leading us to formulate a hypothesis with respect to an electrolyte induced dye reorganization at the surface.

  • 35.
    Gensch, Marc
    et al.
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.;Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Schwartzkopf, Matthias
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Ohm, Wiebke
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Brett, Calvin
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Pandit, Pallavi
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany..
    Varalil, Sarathlal Koyiloth
    Indian Inst Sci, Dept Phys, Bangalore 560012, Karnataka, India..
    Biessmann, Lorenz
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Kreuzer, Lucas P.
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany..
    Drewes, Jonas
    Christian Albrechts Univ Kiel, Inst Mat Wissensch, Lehrstuhl Mat Verbunde, Kaiserstr 2, D-24143 Kiel, Germany..
    Polonskyi, Oleksandr
    Christian Albrechts Univ Kiel, Inst Mat Wissensch, Lehrstuhl Mat Verbunde, Kaiserstr 2, D-24143 Kiel, Germany..
    Strunskus, Thomas
    Christian Albrechts Univ Kiel, Inst Mat Wissensch, Lehrstuhl Mat Verbunde, Kaiserstr 2, D-24143 Kiel, Germany..
    Faupel, Franz
    Christian Albrechts Univ Kiel, Inst Mat Wissensch, Lehrstuhl Mat Verbunde, Kaiserstr 2, D-24143 Kiel, Germany..
    Stierle, Andreas
    Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.;Univ Hamburg, Phys Dept, Luruper Chaussee 149, D-22761 Hamburg, Germany..
    Mueller-Buschbaum, Peter
    Tech Univ Munich, Phys Dept, Lehrstuhl Funkt Mat, James Franck Str 1, D-85748 Garching, Germany.;Tech Univ Munich, Heinz Maier Leibniz Zentrum MLZ, Lichtenbergstr 1, D-85748 Garching, Germany..
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Deutsch Elekt Synchrotron DESY, Notkestr 85, D-22607 Hamburg, Germany.
    Correlating Nanostructure, Optical and Electronic Properties of Nanogranular Silver Layers during Polymer-Template-Assisted Sputter Deposition2019Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 32, s. 29416-29426Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tailoring the optical and electronic properties of nanostructured polymer-metal composites demonstrates great potential for efficient fabrication of modern organic optical and electronic devices such as flexible sensors, transistors, diodes, or photovoltaics. Self-assembled polymer metal nanocomposites offer an excellent perspective for creating hierarchical nanostructures on macroscopic scales by simple bottom-up processes. We investigate the growth processes of nanogranular silver (Ag) layers on diblock copolymer thin film templates during sputter deposition. The Ag growth is strongly driven by self-assembly and selective wetting on the lamella structure of polystyrene-block-poly (methyl methacrylate). We correlate the emerging nanoscale morphologies with collective optical and electronic properties and quantify the difference in Ag growth on the corresponding homopolymer thin films. Thus, we are able to determine the influence of the respective polymer template and observe substrate effects on the Ag cluster percolation threshold, which affects the insulator-to-metal transition (IMT). Optical spectroscopy in the UV-vis regime reveals localized surface plasmon resonance for the metal polymer composite. Their maximum absorption is observed around the IMT due to the subsequent long-range electron conduction in percolated nanogranular Ag layers. Using X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy, we identify the oxidation of Ag at the acrylate side chains as an essential influencing factor driving the selective wetting behavior in the early growth stages. The results of polymer-templated cluster growth are corroborated by atomic force microscopy and field emission scanning electron microscopy.

  • 36.
    Ghanadpour, Maryam
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Carosio, F.
    Ruda, M. C.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Tuning the Nanoscale Properties of Phosphorylated Cellulose Nanofibril-Based Thin Films to Achieve Highly Fire-Protecting Coatings for Flammable Solid Materials2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 38, s. 32543-32555Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultrathin nanocomposite films were prepared by combining cellulose nanofibrils (CNFs) prepared from phosphorylated pulp fibers (P-CNF) with montmorillonite (MMT), sepiolite (Sep) clay, or sodium hexametaphosphate (SHMP). The flame-retardant and heat-protective capability of the prepared films as casings for a polyethylene (PE) film was investigated. Heating the coated PE in air revealed that the polymer film was thoroughly preserved up to at least 300 °C. The P-CNF/MMT coatings were also able to completely prevent the ignition of the PE film during cone calorimetry, but neither the P-CNF/Sep nor the P-CNF/SHMP coating could entirely prevent PE ignition. This was explained by the results from combined thermogravimetry Fourier transform infrared spectroscopy, which showed that the P-CNF/MMT film was able to delay the release of PE decomposition volatiles and shift its thermal degradation to a higher temperature. The superior flame-retardant performance of the P-CNF/MMT films is mainly attributed to the unique compositional and structural features of the film, where P-CNF is responsible for increasing the char formation, whereas the MMT platelets create excellent barrier and thermal shielding properties by forming inorganic lamellae within the P-CNF matrix. These films showed a tensile strength of 304 MPa and a Young's modulus of 15 GPa with 10 wt % clay so that this composite film was mechanically stronger than the previously prepared CNF/clay nanopapers containing the same amount of clay. 

  • 37. Golda-Cepa, M.
    et al.
    Chorylek, A.
    Chytrosz, P.
    Brzychczy-Wloch, M.
    Jaworska, J.
    Kasperczyk, J.
    Hakkarainen, M.
    Engvall, Klas
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Kotarba, A.
    Multifunctional PLGA/Parylene C Coating for Implant Materials: An Integral Approach for Biointerface Optimization2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 34, s. 22093-22105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Functionalizing implant surfaces is critical for improving their performance. An integrated approach was employed to develop a multifunctional implant:coating based on oxygen plasma-modified parylene C and drug-loaded, biodegradable poly(DL-lactide-co-glycolide) (PLGA). The key functional attributes of the coating (i.e., anti-corrosion, biocompatible, anti-infection, and therapeutic) were thoroughly characterized at each fabrication step by spectroscopic, microscopic, and biologic methods and at different scales, ranging from molecular, through the nano- and microscales to the macroscopic scale. The chemistry of each layer was demonstrated separately, and their mutual affinity was shown to be indispensable for the development of versatile coatings, for implant applications.

  • 38. Gorgin Karaji, Z.
    et al.
    Speirs, M.
    Dadbakhsh, S.
    Kruth, J. P.
    Weinans, H.
    Zadpoor, A. A.
    Amin Yavari, S.
    Additively Manufactured and Surface Biofunctionalized Porous Nitinol2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252Artikkel i tidsskrift (Fagfellevurdert)
  • 39.
    Gustafsson, Emil
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center. McMaster University, Canada.
    Pelton, Robert
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Rapid Development of Wet Adhesion between Carboxymethylcellulose Modified Cellulose Surfaces Laminated with Polyvinylamine Adhesive2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 36, s. 24161-24167Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The surface of regenerated cellulose membranes was modified by irreversible adsorption-of carboxymethylcellulose (CMC). Pairs of wet CMC-modified membranes were laminated with polyvinylamine (PVAm) at room, temperature, and the delamination force for wet membranes was measured for both dried and never-dried laminates. The wet adhesion was, studied as a function of PVAm molecular weight, amine :content,: and deposition pH of the polyelectrolyte. Surprisingly the PVAm CMC system gave substantial wet adhesion that exceeded that of TEMPO-oxidized membranes with PVAm for both dried and never-dried laminates. The greatest wet adhesion was achieved for fully hydrolyzed high molecular weight PVAm. Bulk carboxymethylation of cellulose membranes gave inferior wet adhesion combined with PVAm as compared to CMC adsorption which indicates,that a CMC layer of the order of 10 nm Was necessary. There are no obvious covalent cross linking reactions between CMC and PVAm at room temperature, and on the basis of our results, we are instead attributing the wet adhesion to complex formation between the PVAm and the irreversibly adsorbed CMC at the cellulose surface. We propose that interdigitation of PVAm chains into the CMC layer is responsible for the wet adhesion values.

  • 40. Hao, Yan
    et al.
    Saygili, Yasemin
    Cong, Jiayan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Eriksson, Anna
    Yang, Wenxing
    Zhang, Jinbao
    Polanski, Enrico
    Nonomura, Kazuteru
    Zakeeruddin, Shaik Mohammed
    Gratzel, Michael
    Hagfeldt, Anders
    Boschloo, Gerrit
    Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 48, s. 32797-32804Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-pi-A dye (Dyenamo Blue), based on the diketopyrrolopyrrole (DPP)-core, has been designed and synthesized. Assembled with the cobalt bipyridine-based electrolytes, the device with Dyenamo Blue achieved a satisfying efficiency of 7.3% under one sun (AM1.5 G). The co-sensitization strategy was further applied on this blue organic dye together with a red D-pi-A dye (D35). The successful co-sensitization outperformed a panchromatic light absorption and improved the photocurrent density; this in addition to the open-circuit potential result in an efficiency of 8.7%. The extended absorption of the sensitization and the slower recombination reaction between the blue dye and TiO2 surface inhibited by the additional red sensitizer could be the two main reasons for the higher performance. In conclusion, from the results, the highly efficient cobalt-based DSSCs could be achieved with the co-sensitization between red and blue D-pi-A organic dyes with a proper design, which showed us the possibility of applying this strategy for future high-performance solar cells.

  • 41. Hoang, Minh Tam
    et al.
    Pham, Ngoc Duy
    Han, Ji Hun
    Gardner, James M.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Oh, Ilwhan
    Integrated Photoelectrolysis of Water Implemented On Organic Metal Halide Perovskite Photoelectrode2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 19, s. 11904-11909Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein we report on integrated photoelectrolysis of water employing organic metal halide (OMH) perovskite material. Generic OMH perovskite material and device architecture are highly susceptible to degradation by moisture and water. We found that decomposition of perovskite devices proceeds by water ingress through pinholes in upper layers and is strongly affected by applied bias/light and electrolyte pH. It was also found that a pinhole-free hole transport layer (HTL) could significantly enhance the stability of the perovskite photoelectrode, thereby extending the photoelectrode lifetime to several tens of minutes, which is an unprecedented record-long operation. Furthermore, a carbon nanotube (CNT)/polymer composite layer was developed that can effectively protect the underlying perovskite layer from electrolyte molecules.

  • 42. Hou, Jungang
    et al.
    Sun, Yiqing
    Cao, Shuyan
    Wu, Yunzhen
    Chen, Hong
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Graphene Dots Embedded Phosphide Nanosheet-Assembled Tubular Arrays for Efficient and Stable Overall Water Splitting2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 29, s. 24600-24607Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bifunctional electrocatalysts are highly desired for overall water splitting. Herein, the design and fabrication of three-dimensional (3D) hierarchical earth-abundant transition bimetallic phosphide arrays constructed by one-dimensional tubular array that was derived from assembling two-dimensional nanosheet framework has been reported by tailoring the Co/Ni ratio and tunable morphologies, and zero-dimensional (0D) graphene dots were embedded on Co-Ni phosphide matrix to construct 0D/2D tubular array as a highly efficient electrode in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). On the basis of advanced merits, such as the high surface-active sites, well-dispersed graphene dots, and enhanced electron transfer capacity as well as the confinement effect of the graphene dots on the nanosheets, the integrated GDs/Co0.8Ni0.2P tubular arrays as anode and cathode exhibit excellent OER and HER performance. By use of GDs/Co0.8Ni0.2 arrays in the two-electrode setup of the device, a remarkable electrocatalytic performance for full water splitting has been achieved with a high current density of 10 mA cm-2 at 1.54 V and outstanding long-term operation stability in an alkaline environment, indicating a promising system based on nonprecious-metal electrocatalysts toward potential practical devices of overall water splitting.

  • 43.
    Hu, Maowei
    et al.
    Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China..
    Shen, Junyu
    Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China..
    Yu, Ze
    Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China..
    Liao, Rong-Zhen
    Huazhong Univ Sci & Technol, Sch Chem & Chem Engn, Key Lab Mat Chem Energy Convers & Storage, Minist Educ, Wuhan 430074, Hubei, Peoples R China..
    Gurzadyan, Gagik G.
    Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China..
    Yang, Xichuan
    Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Lab Photomol Sci, CH-1015 Lausanne, Switzerland..
    Wang, Mei
    Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Dalian Univ Technol, Inst Artificial Photosynth, Inst Energy Sci & Technol, State Key Lab Fine Chem,DUT KTH Joint Educ & Res, Dalian 116024, Peoples R China.
    Efficient and Stable Dye-Sensitized Solar Cells Based on a Tetradentate Copper(II/I) Redox Mediator2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 36, s. 30409-30416Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The identification of an efficient and stable redox mediator is of paramount importance for commercialization of dye-sensitized solar cells (DSCs). Herein, we report a new class of copper complexes containing diamine-dipyridine tetradentate ligands (L1 = N,N'-dibenzyl-N,N'-bis-(pyridin-2-ylmethyl)ethylenediamine; L2 = N,N'-dibenzyl-N,N'-bis (6-methyl-pyridin-2-ylmethyl)ethylenediamine) as redox mediators in DSCs. Devices constructed with [Cu(L2)](2+/+) redox couple afford an impressive power conversion efficiency (PCE) of 9.2% measured under simulated one sun irradiation (100 mW cm(-2), AM 1.5G), which is among the top efficiencies reported thus far for DSCs with copper complex-based redox mediators. Remarkably, the excellent air, photo, and electrochemical stability of the [Cu(L2)](2+/+) complexes renders an outstanding long-term stability of the whole DSC device, maintaining similar to 90% of the initial efficiency over 500 h under continuous full sun irradiation. This work unfolds a new platform for developing highly efficient and stable redox mediators for large-scale application of DSCs.

  • 44.
    Huang, Jing
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Xu, Bo
    KTH, Skolan för kemivetenskap (CHE), Kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Yuan, Chunze
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Chen, Hong
    Sun, Junliang
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Improved Performance of Colloidal CdSe Quantum Dot-Sensitized Solar Cells by Hybrid Passivation2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 21, s. 18808-18815Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A hybrid passivation strategy is employed to modify the surface of colloidal CdSe quantum dots (QDs) for quantum dot-sensitized solar cells (QDSCs), by using mercaptopropionic acid (MPA) and iodide anions through a ligand exchange reaction in solution. This is found to be an effective way to improve the performance of QDSCs based on colloidal QDs. The results show that MPA can increase the coverage of the QDs on TiO2 electrodes and facilitate the hole extraction from the photoxidized QDs, and simultaneously, that the iodide anions can remedy the surface defects of the CdSe QDs and thus reduce the recombination loss in the device. This hybrid passivation treatment leads to a significant enhancement of the power conversion efficiency of the QDSCs by 41%. Furthermore, an optimal ratio of iodide ions to MPA was determined for favorable hybrid passivation; results show that excessive iodine anions are detrimental to the loading of the QDs. This study demonstrates that the improvement in QDSC performance can be realized by using a combination of different functional ligands to passivate the QDs, and that ligand exchange in solution effective approach to introduce can be an different ligands.

  • 45.
    Höglund, Anders
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Crucial Differences in the Hydrolytic Degradation between Industrial Polylactide and Laboratory-Scale Poly(L-lactide)2012Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 4, nr 5, s. 2788-2793Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rate of degradation of large-scale synthesized polylactide (PLA) of industrial origin was compared with that of laboratory-scale synthesized poly(L-lactide) (PLLA) of similar molar mass. The structural discrepancy between the two material types resulted in a significant difference in degradation rate. Although the hydrolysis of industrial PLA was substantially faster than that of PLLA, the PLA material became less brittle and fragmented to a lesser extent during degradation. In addition, a comprehensive picture of the degradation of industrial PLA was obtained by subjecting different PLA materials to hydrolytic degradation at various temperatures and pH's for up to 182 days. The surrounding environment had no effect on the degradation rate at physiological temperature, but the degradation was faster in water than in a phosphate buffer after prolonged degradation at temperatures above the T-g. The degree of crystallinity had a greater influence than the degradation environment on the rate of hydrolysis. For a future use of polylactide in applications where bulk plastics are generally used today, for example plastic packages, the appropriate PLA grade must be chosen based on the conditions prevailing in the degradation environment.

  • 46.
    Jacques, Eric
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Lindbergh, Göran
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Zenkert, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Leijonmarck, Simon
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Tillämpad elektrokemi.
    Hellqvist Kjell, Maria
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Piezo-Electrochemical Energy Harvesting with Lithium-Intercalating Carbon Fibers2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 25, s. 13898-13904Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanical and electrochemical properties are coupled through a piezo-electrochemical effect in Li-intercalated carbon fibers. It is demonstrated that this piezo-electrochemical effect makes it possible to harvest electrical energy from mechanical work. Continuous polyacrylonitrile-based carbon fibers that can work both as electrodes for Li-ion batteries and structural reinforcement for composites materials are used in this study. Applying a tensile force to carbon fiber bundles used as Li-intercalating electrodes results in a response of the electrode potential of a few millivolts which allows, at low current densities, lithiation at higher electrode potential than delithiation. More electrical energy is thereby released from the cell at discharge than provided at charge, harvesting energy from the mechanical work of the applied force. The measured harvested specific electrical power is in the order of 1 muW/g for current densities in the order of 1 mA/g, but this has a potential of being increased significantly.

  • 47.
    Jafarzadeh, Shadi
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Claesson, Per Martin
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap. SP Technical Research Institute of Sweden, Sweden.
    Sundell, Per-Erik
    Pan, Jinshan
    KTH, Skolan för kemivetenskap (CHE), Kemi, Yt- och korrosionsvetenskap.
    Thormann, Esben
    Nanoscale Electrical and Mechanical Characteristics of Conductive Polyaniline Network in Polymer Composite Films2014Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, nr 21, s. 19168-19175Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The presence and characteristics of a connected network of polyaniline (PANI) within a composite coating based on polyester acrylate (PEA) has been investigated. The bulk electrical conductivity of the composite was measured by impedance spectroscopy. It was found that the composite films containing PANI have an electrical conductivity level in the range of semiconductors (order of 10–3 S cm–1), which suggests the presence of a connected network of the conductive phase. The nanoscopic distribution of such a network within the cured film was characterized by PeakForce tunneling atomic force microscopy (AFM). This method simultaneously provides local information about surface topography and nanomechanical properties, together with electrical conductivity arising from conductive paths connecting the metallic substrate to the surface of the coating. The data demonstrates that a PEA-rich layer exists at the composite–air interface, which hinders the conductive phase to be fully detected at the surface layer. However, by exposing the internal structure of the composites using a microtome, a much higher population of a conductive network of PANI, with higher elastic modulus than the PEA matrix, was observed and characterized. Local current–voltage (IV) spectroscopy was utilized to investigate the conduction mechanism within the nanocomposite films, and revealed non-Ohmic characteristics of the conductive network.

  • 48. Jana, Avijit
    et al.
    Bai, Linyi
    Li, Xin
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Zhao, Yanli
    Morphology Tuning of Self-Assembled Perylene. Monoimide from Nanoparticles to Colloidosomes with Enhanced Excimeric NIR Emission for Bioimaging2016Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 8, nr 3, s. 2336-2347Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Organic near-infrared (NIR) fluorescent probes have been recognized as an emerging class of materials exhibiting a great potential in advanced bioanalytical applications. However, synthesizing such organic probes that could simultaneously work in the NIR spectral range and have large Stokes shift, high stability in biological systems, and high photostability have been proven challenging. In this work, aggregation induced excimeric NIR emission in aqueous media was observed from a suitably substituted perylene monoimide (PeIm) dye. Controlled entrapment of the dye into pluronic F127 micellar system to preserve its monomeric green emission in aqueous media was also established. The aggregation process of the PeIm dye to form organic nanoparticles (NPs) was evaluated experimentally by the means of transmission electron microscope imaging as well as theoretically by the molecular dynamics simulation studies. Tuning the morphology along with the formation of colloidosomes by the controlled self-aggregation of PeIm NPs in aqueous suspension was demonstrated successfully. Finally, both excimeric and monomeric emissive PeIm NPs as well as PeIm colloidosomes were employed for the bioimaging in vitro.

  • 49. Jena, Naresh K.
    et al.
    Araujo, Rafael B.
    Shukla, Vivekanand
    Ahuja, Rajeev
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik. Uppsala University, Sweden.
    Borophane as a Benchmate of Graphene: A Potential 2D Material for Anode of Li and Na-Ion Batteries2017Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, nr 19, s. 16148-16158Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Borophene, single atomic-layer sheet of boron (Science 2015, 350, 1513), is a rather new entrant into the burgeoning class of 2D materials. Borophene exhibits anisotropic metallic properties whereas its hydrogenated counterpart borophane is reported to be a gapless Dirac material lying on the same bench with the celebrated graphene. Interestingly, this transition of borophane also rendered stability to it considering the fact that borophene was synthesized under ultrahigh vacuum conditions on a metallic (Ag) substrate. On the basis of first-principles density functional theory computations, we have investigated the possibilities of borophane as a potential Li/Na-ion battery anode material. We obtained a binding energy of -2.58 (-1.08 eV) eV for Li (Na)-adatom on borophane and Bader charge analysis revealed that Li(Na) atom exists in Li+(Na+) state. Further, on binding with Li/Na, borophane exhibited metallic properties as evidenced by the electronic band structure. We found that diffusion pathways for Li/Na on the borophane surface are anisotropic with x direction being the favorable one with a barrier of 0.27 and 0.09 eV, respectively. While assessing the Li-ion anode performance, we estimated that the maximum Li content is Li0.445B2H2, which gives rises to a material with a maximum theoretical specific capacity of 504 mAh/g together with an average voltage of 0.43 V versus Li/Li+. Likewise, for Na-ion the maximum theoretical capacity and average voltage were estimated to be 504 mAh/g and 0.03 V versus Na/Na+, respectively. These findings unambiguously suggest that borophane can be a potential addition to the map of Li and Na-ion anode materials and can rival some of the recently reported 2D materials including graphene.

  • 50. Kamra, Tripta
    et al.
    Xu, Changgang
    Montelius, Lars
    Schnadt, Joachim
    Wijesundera, Samurdhi A.
    Yan, Mingdi
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi. University of Massachusetts Lowell, United States.
    Ye, Lei
    Photoconjugation of Molecularly Imprinted Polymer Nanoparticles for Surface-Enhanced Raman Detection of Propranolol2015Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, nr 49, s. 27479-27485Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report a simple and versatile method to covalently immobilize molecularly imprinted polymer (MIP) nanoparticles on a Raman active substrate (Klarite) using a disulfide-derivatized perfluorophenylazide (PFPA-disulfide). Gold-coated Klarite was functionalized with PFPA-disulfide via a gold sulfur bond. Upon light radiation, the available azido groups were converted to highly reactive singlet perfluorophenyl nitrene that undergoes a CH insertion reaction and form covalent bonds with the MIP nanoparticles. The resulting surfaces were characterized using scanning electron microscopy and surface enhanced Raman spectroscopy to study the morphology and template affinity of the surfaces, respectively. The Raman measurements clearly show a dose-responsive signal when propranolol binds to the MIP surface. Because the MIP particles were covalently attached to the Raman active substrate, the sensing surface was stable and could be reused after regeneration in acetic acid solution. The MIP-based Raman sensor was used successfully to detect propranolol in urine samples (7.7 X 10(-4) M). Our results show that the high selectivity of MLPs and the fingerprint Raman identification can be integrated into a compact sensing unit using high-efficiency photoconjugation. Thus, the method proposed is reliable, efficient and fast for fabricating label-free chemical sensors.

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