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  • 1.
    Adolfsson, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Carbon flake coated cellulose filters as dual function devices for rapid environmental contaminant detectionManuscript (preprint) (Other academic)
  • 2.
    Adolfsson, Karin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hydrothermal recycling of natural and synthetic polymers to functional carbon materials2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Utilizing renewable recourses and waste recycling are necessary for reaching a circular resource society. The concept of this thesis was to set up a sustainable recycling route, suitable even for low quality biopolymer and plastic waste for production of functional carbon materials. Carbonaceous materials were prepared by mild hydrothermal carbonizations of cellulose and polypropylene (PP) under acidic conditions. The carbonization of cellulose resulted mainly in micro-/nanometer sized carbon spheres (CS) with polar functionalities. After carbonization of PP, products were found in solid and liquid phase. Completely carbonized solid carbons products were obtained from PP at 250 °C after 60 min. The liquid products from the same process displayed aromatics and exhibited fluorescence properties. In addition, new carbon materials were prepared by acid, base and thermal treatments of the carbonized products at low temperatures. Thermally resistant carbon products and antibacterial CS towards both Staphylococcus aureus and Pseudomonas aeruginosa were demonstrated as possible applications for these products. The minimum inhibitory concentrations of CS were 200-400 µg mL-1 depending on the bacteria strain and reached after only 3 h. Furthermore, nanometer sized carbon nanodots with high oxygenation degree and fluorescence properties were derived together with carbon flakes (CF) from the carbonized products. The CF with flat and micrometer sized morphology and polar groups were utilized for coating of cationized cellulose filters, applied as adsorbents and then subsequently as surfaces for SALDI-MS analysis of environmental contaminants. This work contributes with new routes to and applications for functional carbon materials.

    The full text will be freely available from 2020-04-30 10:30
  • 3.
    Adolfsson, Karin H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Golda-Cepa, M
    Benyahia Erdal, Nejla
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Duch, J
    Kotarba, A
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Importance of Surface Functionalities for Antibacterial Properties of Carbon Spheres2019In: Advanced Sustainable Systems, ISSN 2366-7486Article in journal (Refereed)
    Abstract [en]

    Carbon spheres (CS) are interesting materials for antibacterial applications. Herein, CS are produced by a green process utilizing microwave-assisted hydrothermal treatment of cellulose. The CS are then postmodified in acidic and basic solutions to evaluate the influence of different functionalities on antibacterial properties. CS contain OH/COOH, C Symbol of the Klingon Empire C, and C Symbol of the Klingon Empire O functionalities, while O-CS produced by acid treatment of CS have additional COOH, and NH/NH2 groups, resulting in carbon spheres with negatively and positively charged groups in dispersion. Treatment with base (Na-CS) removes low molecular weight species with oxygen and results in carbon spheres with the highest C/O ratio. CS, O-CS, and Na-CS have nonporous morphology and are in micro/nanometer sizes, although, smaller sized spheres, hollow spheres, and fragments are also attained in the case of O-CS. O-CS show antibacterial activity toward both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Pseudomonas aeruginosa (P. aeruginosa). The minimum inhibitory concentration is 200 and 400 mu g mL(-1) for S. aureus and P. aeruginosa, respectively, and is achieved only after 3 h of incubation. Neither CS nor Na-CS exhibit antibacterial activity. The antibacterial activity is suggested to originate from electrostatic interactions between O-CS and the bacteria.

  • 4.
    Adolfsson, Karin H.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hassanzadeh, Salman
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Valorization of cellulose and waste paper to graphene oxide quantum dots2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 34, p. 26550-26558Article in journal (Refereed)
    Abstract [en]

    Biobased graphene oxide quantum dots (GOQD) were derived from cellulose via carbon nanospheres (CN) as intermediate products. Solid CN were synthesized from cellulose through microwave-assisted hydrothermal degradation of alpha-cellulose with H2SO4 as a catalyst at 160 degrees C. The obtained CN were further utilized for the synthesis of GOQD by a two-step reaction including 30 minutes of sonication followed by heating at 90 degrees C under O-rich acidic conditions (HNO3). This process broke down the 3D CN to 2D GOQD. The size of the synthesized GOQD was controlled by the heating time, reaching a dot diameter of 3.3 nm and 1.2 nm after 30 and 60 minutes of heating, respectively. The synthesis process and products were characterized by multiple analytical techniques including FTIR, TGA, SEM, TEM, XPS, XRD, BET, DLS and AFM. Interesting optical properties in aqueous solutions were demonstrated by UV/Vis and fluorescence spectroscopy. Finally we demonstrated that corresponding GOQD can be synthesized from waste paper. This production route thus uses renewable and cheap starting materials and relatively mild synthesis procedures leads to instant nanometric production of 2D dots. In addition it enables recycling of low quality waste to value-added products.

  • 5.
    Adolfsson, Karin H.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Sch Chem Sci & Engn, Stockholm, Sweden..
    Hassanzadeh, Salman
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Sch Chem Sci & Engn, Stockholm, Sweden..
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Sch Chem Sci & Engn, Stockholm, Sweden..
    Value-added carbon products attained through microwave assisted hydrothermal treatment of cellulose and waste paper2016In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Article in journal (Other academic)
  • 6.
    Adolfsson, Karin H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Lin, Chia-feng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Microwave Assisted Hydrothermal Carbonization and Solid State Postmodification of Carbonized Polypropylene2018In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, no 8, p. 11105-11114Article in journal (Refereed)
    Abstract [en]

    Functional carbon materials produced through a hydrothermal treatment of waste products have gained interest. Particularly, the method is considered more facile and green compared to conventional decomposition methods. Here, we demonstrated an upcycling of polypropylene (PP) waste to carbon materials by a microwave assisted hydro thermal treatment. The solid product obtained from the hydrothermal treatment was analyzed by multiple techniques to reveal the structure and the influence of processing conditions on PP degradation and hydrothermal carbonization. Chemical analyses showed the presence of carbonaceous material independent of acid amount (20 and 30 mL), temperature (210 and 250 degrees C), and time (20-80 min). A complete transformation of PP content to amorphous carbon required 60 min at 250 degrees C. The mass yield of the solid product decreased as a function of harsher processing conditions. At the same time, thermogravimetric analysis illustrated products with increasing thermal stability and a larger amount of remaining residue at 600 degrees C. The solid products consisted of irregular fragments and sheet-like structures. A solid state microwave process in air atmosphere was performed on a product with incomplete carbonization. The modification resulted in a decreased C/O ratio, and TGA analysis in nitrogen showed high thermal stability and degree of carbonization as indicated by the remaining residue of 86.4% at 600 degrees C. The new insights provided on the hydrothermal carbonization, and postmodification in air atmosphere, can catalyze effective handling of plastic waste by enabling transformation of low quality waste into functional carbon materials.

  • 7.
    Adolfsson, Karin H.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Xie, L.
    Hassanzadeh, Salman
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Fibre Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Zero-Dimensional and Highly Oxygenated Graphene Oxide for Multifunctional Poly(lactic acid) Bionanocomposites2016In: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 4, no 10, p. 5618-5631Article in journal (Refereed)
    Abstract [en]

    The unique strengths of 2D graphene oxide nanosheets (GONSs) in polymer composites are thwarted by nanosheet agglomeration due to strong intersheet attractions. Here, we reveal that shrinking the planar size to 0D graphene oxide quantum dots (GOQDs), together with the intercalation of rich oxygen functional groups, reduces filler aggregation and enhances interfacial interactions with the host polymer. With poly(lactic acid) (PLA) as a model matrix, atomic force microscopy colloidal probe measurements illustrated that a triple increase in adhesion force to PLA was achieved for GOQDs (234.8 nN) compared to GONSs (80.4 nN), accounting for the excellent exfoliation and dispersion of GOQDs in PLA, in contrast to the notable agglomeration of GONSs. Although present at trace amount (0.05 wt %), GOQDs made a significant contribution to nucleation activity, mechanical strength and ductility, and gas barrier properties of PLA, which contrasted the inferior efficacy of GONSs, accompanied by clear distinction in film transparency (91% and 50%, respectively). Moreover, the GOQDs with higher hydrophilicity accelerated the degradation of PLA by enhancing water erosion, while the GONSs with large sheet surfaces gave a higher hydrolytic resistance. Our findings provide conceptual insights into the importance of the dimensionality and surface chemistry of GO nanostructures in the promising field of bionanocomposites integrating high strength and multifunction (e.g., enhanced transparency, degradation and gas barrier).

  • 8.
    Benyahia Erdal, Nejla
    et al.
    KTH, School of Chemical Science and Engineering (CHE). Royal Inst Technol, Sch Chem Sci & Engn, Stockholm, Sweden..
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE). Sch Chem Sci & Engn, Stockholm, Sweden..
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. Royal Inst Technol, Stockholm, Sweden..
    Silicone-hydrogel bandage lenses used in conjunction with pharmaceutical eye drops: An uptake and release study2016In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Article in journal (Other academic)
  • 9.
    Benyahia Erdal, Nejla
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Pettersson, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Green Strategy to Reduced Nanographene Oxide through Microwave Assisted Transformation of Cellulose2018In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, no 1, p. 1245-1255Article in journal (Refereed)
    Abstract [en]

    A green strategy for fabrication of biobased reduced nanographene oxide (r-nGO) was developed. Cellulose derived nanographene oxide (nGO) type carbon nanodots were reduced by microwave assisted hydrothermal treatment with superheated water alone or in the presence of caffeic acid (CA), a green reducing agent. The carbon nanodots, r-nGO and r-nGO-CA, obtained through the two different reaction routes without or with the added reducing agent, were characterized by multiple analytical techniques including FTIR, XPS, Raman, XRD, TGA, TEM, AFM, UV-vis, and DLS to confirm and evaluate the efficiency of the reduction reactions. A significant decrease in oxygen content accompanied by increased number of sp2 hybridized functional groups was confirmed in both cases. The synergistic effect of superheated water and reducing agent resulted in the highest C/O ratio and thermal stability, which also supported a more efficient reduction. Interesting optical properties were detected by fluorescence spectroscopy where nGO, r-nGO, and r-nGO-CA all displayed excitation dependent fluorescence behavior. r-nGO-CA and its precursor nGO were evaluated toward osteoblastic cells MG-63 and exhibited nontoxic behavior up to 200 μg mL-1, which gives promise for utilization in biomedical applications.

  • 10.
    Delekta, Szymon Sollami
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics.
    Adolfsson, Karin H.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Benyahia Erdal, Nejla
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    Östling, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics.
    Li, Jiantong
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics.
    Fully inkjet printed ultrathin microsupercapacitors based on graphene electrodes and a nano-graphene oxide electrolyte2019In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 21, p. 10172-10177Article in journal (Refereed)
    Abstract [en]

    The advance of miniaturized and low-power electronics has a striking impact on the development of energy storage devices with constantly tougher constraints in terms of form factor and performance. Microsupercapacitors (MSCs) are considered a potential solution to this problem, thanks to their compact device structure. Great efforts have been made to maximize their performance with new materials like graphene and to minimize their production cost with scalable fabrication processes. In this regard, we developed a full inkjet printing process for the production of all-graphene microsupercapacitors with electrodes based on electrochemically exfoliated graphene and an ultrathin solid-state electrolyte based on nano-graphene oxide. The devices exploit the high ionic conductivity of nano-graphene oxide coupled with the high electrical conductivity of graphene films, yielding areal capacitances of up to 313 mu F cm-2 at 5 mV s-1 and high power densities of up to 4 mW cm-3 with an overall device thickness of only 1 mu m.

  • 11. Duch, J.
    et al.
    Kubisiak, P.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Golda-Cepa, M.
    Kotarba, A.
    Work function modifications of graphite surface via oxygen plasma treatment2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 419, p. 439-446Article in journal (Refereed)
    Abstract [en]

    The surface modification of graphite by oxygen plasma was investigated experimentally (X-ray diffraction, nanoparticle tracking analysis, laser desorption ionization mass spectrometry, thermogravimetry, water contact angle) and by molecular modelling (Density Functional Theory). Generation of surface functional groups (mainly –OHsurf) leads to substantial changes in electrodonor properties and wettability gauged by work function and water contact angle, respectively. The invoked modifications were analyzed in terms of Helmholtz model taking into account the theoretically determined surface dipole moment of graphite—OHsurf system (μ = 2.71 D) and experimentally measured work function increase (from 0.75 to 1.02 eV) to determine the –OH surface coverage (from 0.70 to 1.03 × 1014 groups cm−2). Since the plasma treatment was confined to the surface, the high thermal stability of the graphite material was preserved as revealed by the thermogravimetric analysis. The obtained results provide a suitable quantitative background for tuning the key operating parameters of carbon electrodes: electronic properties, interaction with water and thermal stability.

  • 12.
    Erdal, Nejla B.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    De Lima, Sara
    Karolinska Inst, St Erik Eye Hosp, Div Ophthalmol & Vis, Dept Clin Neurosci, Stockholm, Sweden..
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymer Technology.
    In vitro and in vivo effects of ophthalmic solutions on silicone hydrogel bandage lens material Senofilcon A2018In: Clinical and experimental optometry, ISSN 0816-4622, E-ISSN 1444-0938, Vol. 101, no 3, p. 354-362Article in journal (Refereed)
    Abstract [en]

    Background: Acuvue Oasys silicone hydrogel contact lenses (Senofilcon A) are used as bandage lenses and often combined with ophthalmic solutions in the treatment of ocular diseases. Concerns have been raised regarding the compatibility and effect of eye-drop solutions on the bandage lenses, which have led to frequent replacement of lenses causing clinical problems. Some patients experience pain or discomfort during treatments and the accumulation of drugs and preservatives in lenses has been suggested as a possible reason. The aim with this study was to investigate the effect of ophthalmic solutions on silicone hydrogel bandage lens material Senofilcon A in vitro and in vivo. Methods: The effect of three common ophthalmic solutions Isopto-Maxidex, Timosan and Oftaquix on Acuvue Oasys (Senofilcon A) bandage lenses was evaluated. An in vitro model method was developed where drug and preservative uptake by Acuvue Oasys was monitored with ultraviolet-visible spectroscopy and laser desorption ionisation mass spectrometry. Surface morphology changes of the lenses were evaluated using scanning electron microscopy. The method was then implemented for the in vivo pilot study evaluating lenses worn by patients. Results: In vitro model study monitoring the drug and preservatives uptake showed that the active ingredients from all the eye drops together with preservatives were taken up by the lenses in significant amounts. For the in vivo study no traces of active ingredients or preservatives could be found on the worn and treated lenses regardless of time being worn or dosage profiles. The surface morphology changes in the in vivo study were also minor in contrast to the changes observed in the in vitro scanning electron microscopy images. Conclusion: The in vivo results demonstrate minor effects of the ophthalmic solutions on the worn lenses. These results do not support the building up of preservatives and drugs on the contact lenses as the cause of pain or discomfort experienced by some patients, which is encouraging for the use of bandage lenses in combination with ophthalmic solutions.

  • 13.
    Gazzotti, Stefano
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology. Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Hakkarainen, Minna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Ortenzi, Marco Aldo
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Farina, Hermes
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Lesma, Giordano
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    Silvani, Alessandra
    Univ Milan, Dept Chem, Via Golgi 19, I-20133 Milan, Italy.;Univ Milan, Dept Chem, CRC Mat Polimerici LaMPO, Via Golgi 19, I-20133 Milan, Italy..
    One-Pot Synthesis of Sustainable High-Performance Thermoset by Exploiting Eugenol Functionalized 1,3-Dioxolan-4-one2018In: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, no 11, p. 15201-15211Article in journal (Refereed)
    Abstract [en]

    1,3-Dioxolan-4-one (DOX) chemistry was explored for production of "one-pot" biobased polyester thermosets. DOX monomer was first functionalized by naturally occurring eugenol to introduce a structural element, which could induce cross-linking reaction through cationic polymerization of the double bond. The feasibility of polymerizing DOX monomers bearing bulky side groups was proven by model phenol-substituted DOX monomer (PhDOX). Once the reaction was shown to be effective, the same protocol was applied to eugenol-substituted monomer (EuDOX). A brief screening of the optimal catalyst concentration was performed, to obtain a highly cross-linked product. The synthesized thermoset showed good thermal resistance and high mechanical strength probably due to the rich aromatic content. The obtained thermoset was further subjected to microwave-assisted hydrothermal degradation test, which demonstrated complete recyclability to water or methanol soluble products. NMR and matrix-assisted laser desorption/ionization-mass spectroscopy analyses of the obtained degradation products unveiled the structure of the thermoset, strongly indicating that the polymerization of eugenol-functionalized DOX monomer resulted in polylactide-like chains connected with aromatic aliphatic segments resulting from the reaction of the eugenol double bonds. The presence of free hydroxyl and carboxyl groups sheds light on the mechanism behind the observed shape-memory and self-healing properties.

  • 14.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Controlling the cooperative self-assembly of graphene oxide quantum dots in aqueous solutions2015In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 5, no 71, p. 57425-57432Article in journal (Refereed)
    Abstract [en]

    Fascinating 3D cooperative self-assembly behavior was observed for 2D graphene oxide quantum dots (GOQDs) in dilute and semi dilute aqueous solutions. In addition the optical properties could be tuned by controlling the supramolecular structures. While the electrostatic interactions between the charged single sheets were assigned as the main secondary interactions that were responsible for the supramolecular fine structures, the concentration, temperature, salt concentration and pH could tune the repulsive/attractive forces and the molecular binding between the GOQD sheets. The morphological studies combined with UV-Vis and fluorescence evaluations proved that after a slow nucleation step, elongation preceded radially by H-aggregate self-association of the GOQD monomers, forming the final porous spheres by radial growth of rods. The quenching properties of the self-associated-assembled GOQDs together with the excitation wavelengths of the GOQD solutions enabled tuning of the fluorescence intensity and color of the final solutions, which could be utilized for e.g. bioimaging and smart spectroscopy.

  • 15.
    Hassanzadeh, Salman
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wu, Duo
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Supramolecular Assembly of Biobased Graphene Oxide Quantum Dots Controls the Morphology of and Induces Mineralization on Poly(epsilon-caprolactone) Films2016In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, no 1, p. 256-261Article in journal (Refereed)
    Abstract [en]

    Biobased 2D graphene oxide quantum dots (GOQDs) were synthesized from waste paper via carbon nanosphere intermediates and evaluated as property-enhancing additives for poly(epsilon-caprolactone) (PCL). The morphology of PCL films was controlled by supramolecular assembly of the small, 2D GOQDs in the polymer matrix. Phase behavior studies of PCL-GOQD in the solid state indicated concentration-dependent self-association of GOQD sheets, which was confirmed by SEM observations. Depending on the GOQD concentration, the formation of, e.g., spheres and stacked sheets was observed. GOQDs also induced mineralization on the surface of the films. A calcium phosphate (CaP) mineralization test revealed that the density of growing CaP crystals was controlled by the type of GOQD aggregates formed. Thus, utilization of the aggregation behavior of small GOQD sheets in polymeric matrices paves the way for tuning the morphology and properties of nanocomposites.

  • 16.
    Xu, Huan
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Wu, Duo
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Yang, Xi
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Feng, Zhaoxuan
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Adolfsson, Karin H.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Xie, Lan
    Sichuan Univ, Dept Polymer Sci & Engn, Chengdu, Sichuan, Peoples R China..
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Enhancing the function of graphene oxide nanosheets by crystallization control: Unexpected harvest of strength, ductility and thermal stability for poly(lactic acid) barrier films2016In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Article in journal (Other academic)
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