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Ciftci, Göksu Cinar
Publications (7 of 7) Show all publications
Jain, K., Wang, Z., Garma, L. D., Engel, E., Ciftci, G. C., Fager, C., . . . Wågberg, L. (2023). 3D printable composites of modified cellulose fibers and conductive polymers and their use in wearable electronics. APPLIED MATERIALS TODAY, 30, Article ID 101703.
Open this publication in new window or tab >>3D printable composites of modified cellulose fibers and conductive polymers and their use in wearable electronics
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2023 (English)In: APPLIED MATERIALS TODAY, ISSN 2352-9407, Vol. 30, article id 101703Article in journal (Refereed) Published
Abstract [en]

There are many bioelectronic applications where the additive manufacturing of conductive polymers may be of use. This method is cheap, versatile and allows fine control over the design of wearable electronic devices. Nanocellulose has been widely used as a rheology modifier in bio-based inks that are used to print electrical components and devices. However, the preparation of nanocellulose is energy and time consuming. In this work an easy-to-prepare, 3D-printable, conductive bio-ink; based on modified cellulose fibers and poly(3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT:PSS), is presented. The ink shows excellent printability, the printed samples are wet stable and show excellent electrical and electrochemical performance. The printed structures have a conductivity of 30 S/cm, high tensile strains (>40%), and specific capacitances of 211 F/g; even though the PEDOT:PSS only accounts for 40 wt% of the total ink composition. Scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS), and Raman spectroscopy data show that the modified cellulose fibers induce conformational changes and phase separation in PEDOT:PSS. It is also demonstrated that wearable supercapacitors and biopotential-monitoring devices can be prepared using this ink.

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
Dialcohol-modified cellulose fibers, 3D printing, Conducting polymer, PEDOT:PSS, Bioelectronics
National Category
Textile, Rubber and Polymeric Materials Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-323583 (URN)10.1016/j.apmt.2022.101703 (DOI)000912019800001 ()2-s2.0-85143488124 (Scopus ID)
Note

QC 20230208

Available from: 2023-02-08 Created: 2023-02-08 Last updated: 2023-02-08Bibliographically approved
Atoufi, Z., Ciftci, G. C., Reid, M. S., Larsson, P. A. & Wågberg, L. (2022). Green Ambient-Dried Aerogels with a Facile pH-Tunable Surface Charge for Adsorption of Cationic and Anionic Contaminants with High Selectivity. Biomacromolecules, 23(11), 4934-4947
Open this publication in new window or tab >>Green Ambient-Dried Aerogels with a Facile pH-Tunable Surface Charge for Adsorption of Cationic and Anionic Contaminants with High Selectivity
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2022 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 23, no 11, p. 4934-4947Article in journal (Refereed) Published
Abstract [en]

The fabrication of reusable, sustainable adsorbents from low-cost, renewable resources via energy efficient methods is challenging. This paper presents wet-stable, carboxymethylated cellulose nanofibril (CNF) and amyloid nanofibril (ANF) based aerogel-like adsorbents prepared through efficient and green processes for the removal of metal ions and dyes from water. The aerogels exhibit tunable densities (18-28 kg m-3), wet resilience, and an interconnected porous structure (99% porosity), with a pH controllable surface charge for adsorption of both cationic (methylene blue and Pb(II)) and anionic (brilliant blue, congo red, and Cr(VI)) model contaminants. The Langmuir saturation adsorption capacity of the aerogel was calculated to be 68, 79, and 42 mg g-1for brilliant blue, Pb(II), and Cr(VI), respectively. Adsorption kinetic studies for the adsorption of brilliant blue as a model contaminant demonstrated that a pseudo-second-order model best fitted the experimental data and that an intraparticle diffusion model suggests that there are three adsorption stages in the adsorption of brilliant blue on the aerogel. Following three cycles of adsorption and regeneration, the aerogels maintained nearly 97 and 96% of their adsorption capacity for methylene blue and Pb(II) as cationic contaminants and 89 and 80% for brilliant blue and Cr(VI) as anionic contaminants. Moreover, the aerogels showed remarkable selectivity for Pb(II) in the presence of calcium and magnesium as background ions, with a selectivity coefficient more than 2 orders of magnitude higher than calcium and magnesium. Overall, the energy-efficient and sustainable fabrication procedure, along with good structural stability, reusability, and selectivity, makes these aerogels very promising for water purification applications.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
Aerogels, Alginate, Aromatic compounds, Azo dyes, Calcium, Cellulose, Energy efficiency, Isotherms, Lead compounds, Magnesium, Metal ions, Nanofibers, Porosity, Reusability, Stability, Stripping (dyes), Adsorption capacities, Ambients, Anionic contaminants, Brilliant Blue, Calcium and magnesiums, Cationic contaminants, Energy efficient, Methylene Blue, Model contaminant, Tunables, Adsorption, aerogel, cellulose nanofiber, chromium, congo red, lead, metal ion, nanofiber, water, anion, cation, chromium hexavalent ion, adsorption kinetics, Article, atmospheric pressure, atomic force microscopy, confocal microscopy, controlled study, freeze drying, ionization, isotherm, oxidation, pH, pore volume, scanning electron microscopy, surface charge, thermogravimetry, titrimetry, water management, zeta potential, chemistry, kinetics, water pollutant, Azo Compounds, Anions, Cations, Hydrogen-Ion Concentration, Water Pollutants, Chemical
National Category
Materials Chemistry Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-329019 (URN)10.1021/acs.biomac.2c01142 (DOI)000879871700001 ()36318480 (PubMedID)2-s2.0-85141671200 (Scopus ID)
Note

QC 20230614

Available from: 2023-06-14 Created: 2023-06-14 Last updated: 2024-01-30Bibliographically approved
Rostami, J., Benselfelt, T., Maddalena, L., Avci, C., Sellman, F. A., Ciftci, G. C., . . . Wågberg, L. (2022). Shaping 90 wt% NanoMOFs into Robust Multifunctional Aerogels Using Tailored Bio-Based Nanofibrils. Advanced Materials, 34(38), Article ID 2204800.
Open this publication in new window or tab >>Shaping 90 wt% NanoMOFs into Robust Multifunctional Aerogels Using Tailored Bio-Based Nanofibrils
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2022 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 34, no 38, article id 2204800Article in journal (Refereed) Published
Abstract [en]

Metal–organic frameworks (MOFs) are hybrid porous crystalline networks with tunable chemical and structural properties. However, their excellent potential is limited in practical applications by their hard-to-shape powder form, making it challenging to assemble MOFs into macroscopic composites with mechanical integrity. While a binder matrix enables hybrid materials, such materials have a limited MOF content and thus limited functionality. To overcome this challenge, nanoMOFs are combined with tailored same-charge high-aspect-ratio cellulose nanofibrils (CNFs) to manufacture robust, wet-stable, and multifunctional MOF-based aerogels with 90 wt% nanoMOF loading. The porous aerogel architectures show excellent potential for practical applications such as efficient water purification, CO2 and CH4 gas adsorption and separation, and fire-safe insulation. Moreover, a one-step carbonization process enables these aerogels as effective structural energy-storage electrodes. This work exhibits the unique ability of high-aspect-ratio CNFs to bind large amounts of nanoMOFs in structured materials with outstanding mechanical integrity—a quality that is preserved even after carbonization. The demonstrated process is simple and fully discloses the intrinsic potential of the nanoMOFs, resulting in synergetic properties not found in the components alone, thus paving the way for MOFs in macroscopic multifunctional composites. 

Place, publisher, year, edition, pages
Wiley, 2022
Keywords
aerogels, cellulose nanofibrils, flame retardancy, gas adsorption and separation, metal–organic frameworks, supercapacitors, water purification, Aspect ratio, Carbonization, Crystalline materials, Gas adsorption, Hybrid materials, Nanocellulose, Nanofibers, Supercapacitor, Bio-based, Crystalline networks, Flame-retardancy, Gas adsorption and separations, High aspect ratio, Mechanical integrity, Metalorganic frameworks (MOFs), Nano-fibrils, Binders, Composites, Loading, Materials, Powder, Processes
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-326793 (URN)10.1002/adma.202204800 (DOI)000840897400001 ()35906189 (PubMedID)2-s2.0-85135930335 (Scopus ID)
Note

QC 20230515

Available from: 2023-05-15 Created: 2023-05-15 Last updated: 2024-05-21Bibliographically approved
Rostami, J., Gordeyeva, K., Benselfelt, T., Lahchaichi, E., Hall, S. A., Riazanova, A., . . . Wågberg, L. (2021). Hierarchical build-up of bio-based nanofibrous materials with tunable metal-organic framework biofunctionality. Materials Today, 48, 47-58
Open this publication in new window or tab >>Hierarchical build-up of bio-based nanofibrous materials with tunable metal-organic framework biofunctionality
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2021 (English)In: Materials Today, ISSN 1369-7021, E-ISSN 1873-4103, Vol. 48, p. 47-58Article in journal (Refereed) Published
Abstract [en]

Multifunctional, light-weight, responsive materials show promise in a range of applications including soft robotics, therapeutic delivery, advanced diagnostics and charge storage. This paper presents a novel, scalable, efficient and sustainable approach for the preparation of cellulose nanofibril-based aerogels via a facile ice-templating, solvent exchange and air-drying procedure, which could replace existing inefficient drying processes. These ambient-dried aerogels (similar to 99% porosity) exhibit a high specific compressive modulus (26.8 +/- 6.1 kPa m(3) kg(-1), approaching equivalence of carbon-nanotubereinforced aerogels), wet stability and shape recovery (80-90%), favorable specific surface area (90 m(2) g(-1)) and tunable densities (2-20 kg m(-3)). The aerogels provide an ideal nanofibrillar substrate for in-situ growth of metal-organic frameworks (MOFs), via co-assembly of MOF precursors with proteins in aqueous solutions. The resulting hybrid aerogels show a nine-fold increase in surface area (810 m(2)g(-1)), with preserved wet stability and additional protein biofunctionality. The hybrid aerogels facilitate a pH-controlled release of immobilized proteins, following a concomitant disassembly of the surface grown MOFs, demonstrating their use in controlled delivery systems. The colorimetric protein binding assay of the biofunctionalized hybrid aerogel also demonstrates the potential of the material as a novel 3D bioassay platform, which could potentially be an alternative to plate-based enzyme-linked immunosorbent assay.

Place, publisher, year, edition, pages
Elsevier BV, 2021
Keywords
3D lightweight materials, Aerogels, Cellulose nanofibrils, Metal-organic frameworks, Controlled release, Protein binding assay
National Category
Materials Chemistry Paper, Pulp and Fiber Technology Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-305086 (URN)10.1016/j.mattod.2021.04.013 (DOI)000711373200009 ()2-s2.0-85106632112 (Scopus ID)
Note

QC 20211123

Available from: 2021-11-23 Created: 2021-11-23 Last updated: 2024-05-21Bibliographically approved
Ciftci, G. C., Larsson, P. A., Riazanova, A., Øvrebø, H., Wågberg, L. & Berglund, L. (2020). Tailoring of rheological properties and structural polydispersity effects in microfibrillated cellulose suspensions. Cellulose, 27(16), 9227-9241
Open this publication in new window or tab >>Tailoring of rheological properties and structural polydispersity effects in microfibrillated cellulose suspensions
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2020 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 27, no 16, p. 9227-9241Article in journal (Refereed) Published
Abstract [en]

Abstract: Industrial production of low-charge microfibrillated cellulose (MFC) typically results in wide fibril size distributions. This polydispersity influences viscosity, overall colloidal stability, and rheological properties of MFC suspensions and gels in aqueous systems. In this work, a systematic rheological analysis is performed for industrially prepared MFC and fractions of different size distributions. Gel formation and flow characteristics (e.g., shear-thinning) of each fraction are examined under neutral and acidic conditions and compared with the unfractionated MFC suspension. The effects of size, aspect ratio, and surface charge on the rheology of semi-dilute MFC suspensions are discussed. The results demonstrate that particle size and aspect ratio distribution control the viscoelasticity and shear-thinning properties of MFC suspensions. An increased fraction of small diameter nanofibrils, by ex situ addition of the fine particles with high aspect ratio or removal of the coarsest particles (with lower aspect ratio) by fractionation, significantly enhances the storage modulus and the yield stress of the complex mixture, compared to the properties of the coarser fractions. New insights are also reported on the tailoring of the rheology of highly polydisperse fibrillar mixtures, where the rheological contributions of each fraction are discussed. Graphic abstract: [Figure not available: see fulltext.].

Place, publisher, year, edition, pages
Springer Science+Business Media B.V., 2020
Keywords
Cellulose nanofibrils, Gel formation, Nanocellulose, Shear-thinning, Viscoelasticity, Cellulose, Cellulose nanocrystals, Elasticity, Mixtures, Non Newtonian flow, Particle size, Particle size analysis, Rheology, Shear flow, Shear thinning, Size distribution, Suspensions (fluids), Yield stress, Aspect ratio distribution, Flow charac-teristics, Industrial production, Microfibrillated cellulose, Microfibrillated cellulose (MFC), Polydispersity effect, Rheological analysis, Rheological property, Aspect ratio
National Category
Fluid Mechanics and Acoustics Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-285338 (URN)10.1007/s10570-020-03438-6 (DOI)000570033300002 ()2-s2.0-85091075460 (Scopus ID)
Note

QC 20201201

Available from: 2020-12-01 Created: 2020-12-01 Last updated: 2024-01-10Bibliographically approved
Larsson, P. A., Riazanova, A., Ciftci, G. C., Rojas, R., Ovrebo, H. H., Wågberg, L. & Berglund, L. (2019). Towards optimised size distribution in commercial microfibrillated cellulose: a fractionation approach. Cellulose, 26(3), 1565-1575
Open this publication in new window or tab >>Towards optimised size distribution in commercial microfibrillated cellulose: a fractionation approach
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2019 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 26, no 3, p. 1565-1575Article in journal (Refereed) Published
Abstract [en]

For the successful commercialisation of microfibrillated cellulose (MFC) it is of utmost importance to carefully characterise the constituent cellulose particles. This could for instance lead to the development of MFC grades with size distributions tailored for specific applications. Characterization of MFC is challenging due to the heterogeneous chemical and structural nature of MFC. This study describes a fractionation approach that combines two steps of physical sieving of larger particles and a final centrifugation step to separate out the smallest, colloidally stable particles, resulting in four distinctly different size fractions. The properties, such as size and charge, of each fraction were studied, as well as MFC filtration time, film formation, and film properties (mechanical and optical). It was found that virtually all surface charges, determined by polyelectrolyte adsorption, are located in the colloidally stable fraction of the MFC. In addition, the amount of available surface charges can be used as an estimate of the degree of fibrillation of the MFC. The partly fibrillated particles frequently displayed a branching, fringed morphology. Mechanical testing of films from the different fractions revealed that the removal of large particles may be more important for strength than achieving full fibrillation. Overall, this study demonstrates that by controlling the size distribution in MFC grades, property profiles including dewatering time to make films by filtration, rheology, film strength and optical transmittance could be optimised. [GRAPHICS] .

Place, publisher, year, edition, pages
Springer, 2019
Keywords
Cellulose nanofibrils, Cellulose films, Fractionation, Microfibrillated cellulose, Nanocellulose, Nanopaper
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-247842 (URN)10.1007/s10570-018-2214-4 (DOI)000460617900011 ()2-s2.0-85059322104 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2024-03-15Bibliographically approved
Ciftci, G. C., Larsson, P., Riazanova, A., Karppinen, A., Ovrebo, H. H., Berglund, L. & Wågberg, L. (2018). Influence of microfibrillated cellulose fractions on the rheology of water suspensions: Colloidal interactions and viscoelastic properties. Paper presented at 256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA. Abstracts of Papers of the American Chemical Society, 256
Open this publication in new window or tab >>Influence of microfibrillated cellulose fractions on the rheology of water suspensions: Colloidal interactions and viscoelastic properties
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2018 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-238558 (URN)000447600003549 ()
Conference
256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond, AUG 19-23, 2018, Boston, MA
Note

QC 20181105

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2024-03-15Bibliographically approved
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