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Benyahia Erdal, Nejla
Publications (6 of 6) Show all publications
Delekta, S. S., Adolfsson, K. H., Benyahia Erdal, N., Hakkarainen, M., Östling, M. & Li, J. (2019). Fully inkjet printed ultrathin microsupercapacitors based on graphene electrodes and a nano-graphene oxide electrolyte. Nanoscale, 11(21), 10172-10177
Open this publication in new window or tab >>Fully inkjet printed ultrathin microsupercapacitors based on graphene electrodes and a nano-graphene oxide electrolyte
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2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 21, p. 10172-10177Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-254076 (URN)10.1039/c9nr01427f (DOI)000470697800002 ()31107494 (PubMedID)2-s2.0-85066626832 (Scopus ID)
Note

QC 20190624

Available from: 2019-06-24 Created: 2019-06-24 Last updated: 2019-08-16Bibliographically approved
Adolfsson, K. H., Golda-Cepa, M., Benyahia Erdal, N., Duch, J., Kotarba, A. & Hakkarainen, M. (2019). Importance of Surface Functionalities for Antibacterial Properties of Carbon Spheres. Advanced Sustainable Systems
Open this publication in new window or tab >>Importance of Surface Functionalities for Antibacterial Properties of Carbon Spheres
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2019 (English)In: Advanced Sustainable Systems, ISSN 2366-7486Article in journal (Refereed) Published
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.

Keywords
antibacterial; carbon spheres; carbonization; electrostatic interactions; microwaves; surface functionality
National Category
Natural Sciences
Identifiers
urn:nbn:se:kth:diva-248712 (URN)10.1002/adsu.201800148 (DOI)000465001800001 ()
Note

QC 20190514

Available from: 2019-04-09 Created: 2019-04-09 Last updated: 2019-05-14Bibliographically approved
Bianchi, F., Agazzi, S., Riboni, N., Benyahia Erdal, N., Hakkarainen, M., Ilag, L. L., . . . Careri, M. (2019). Novel sample-substrates for the determination of new psychoactive substances in oral fluid by desorption electrospray ionization-high resolution mass spectrometry. Talanta: The International Journal of Pure and Applied Analytical Chemistry, 202, 136-144
Open this publication in new window or tab >>Novel sample-substrates for the determination of new psychoactive substances in oral fluid by desorption electrospray ionization-high resolution mass spectrometry
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2019 (English)In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 202, p. 136-144Article in journal (Refereed) Published
Abstract [en]

A reliable screening and non invasive method based on the use of microextraction by packed sorbent coupled with desorption electrospray ionization-high resolution mass spectrometry was developed and validated for the detection of new psychoactive substances in oral fluid. The role of different sample substrates in enhancing signal intensity and stability was evaluated by testing the performances of two polylactide-based materials, i.e. non-functionalized and functionalized with carbon nanoparticles, and a silica-based material compared to commercially available polytetrafluorethylene supports. The best results were achieved by using the non-functionalized polylactide substrates to efficiently ionize compounds in positive ionization mode, whereas the silica coating proved to be the best choice for operating in negative ionization mode. LLOQs in the low μg/L, a good precision with CV% always lower than 16% and RR% in the 83(±4)-120(±2)% range, proved the suitability of the developed method for the determination of the analytes in oral fluid. Finally, the method was applied for screening oral fluid samples for the presence of psychoactive substances during private parties, revealing mephedrone in only one sample out of 40 submitted to analysis.

Place, publisher, year, edition, pages
Elsevier B.V., 2019
Keywords
Desorption electrospray ionization, High resolution mass spectrometry, New psychoactive substances, Sample-substrates, Desorption, Mass spectrometry, Noninvasive medical procedures, Polyesters, Screening, Silica, Carbon Nano-Particles, Micro-extraction by packed sorbents, Noninvasive methods, Polytetrafluorethylene, Silica based materials, Electrospray ionization
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-252452 (URN)10.1016/j.talanta.2019.04.057 (DOI)000472693700015 ()2-s2.0-85064881748 (Scopus ID)
Note

QC 20190715

Available from: 2019-07-15 Created: 2019-07-15 Last updated: 2019-07-29Bibliographically approved
Benyahia Erdal, N., Hakkarainen, M. & Blomqvist, A. (2019). Polymer, giant molecules with properties: An entertaining activity introducing polymers to young students. Journal of Chemical Education, 96(8), 1691-1695
Open this publication in new window or tab >>Polymer, giant molecules with properties: An entertaining activity introducing polymers to young students
2019 (English)In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 96, no 8, p. 1691-1695Article in journal (Refereed) Published
Abstract [en]

In this activity, polymer materials are introduced to 13–16 year old students. The activity is aimed at students with no or little knowledge of polymers. An engaging lecture covering the basics of polymer technology and sustainable development in the plastics field is presented. Important polymers such as polyethylene (PE), cellulose, and polylactide (PLA) are presented, and examples of their everyday use are shown. Quiz questions are employed in the introductory lecture to engage the students, to start discussions, and to evaluate the learning progress. The students are then engaged in two entertaining activities involving a natural polymer alginate and superabsorbent polymers. Alginate spaghetti is produced using different salt solutions enabling the students to create and destroy materials just by playing around with the chemistry, which helps them understand the polymeric material. The second activity has an application-based approach where the ability of superabsorbent polymers in diapers to retain water is investigated. The overall quiz results and discussions after the activities show an improved understanding of polymers and their applications and properties, making this activity useful for teaching polymers to young students.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
polymer chemistry, outreach, hydrogel. polymer, high school students
National Category
Polymer Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-259684 (URN)10.1021/acs.jchemed.8b00918 (DOI)2-s2.0-85067025783 (Scopus ID)
Note

QC 20191015

Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2019-10-15Bibliographically approved
Benyahia Erdal, N., Adolfsson, K. H., Pettersson, T. & Hakkarainen, M. (2018). Green Strategy to Reduced Nanographene Oxide through Microwave Assisted Transformation of Cellulose. ACS Sustainable Chemistry and Engineering, 6(1), 1245-1255
Open this publication in new window or tab >>Green Strategy to Reduced Nanographene Oxide through Microwave Assisted Transformation of Cellulose
2018 (English)In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, no 1, p. 1245-1255Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
Biobased, Biomass, Carbon nanodots, Hydrothermal, Microwave, Reducing agent
National Category
Other Chemical Engineering Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-221151 (URN)10.1021/acssuschemeng.7b03566 (DOI)000419536800131 ()2-s2.0-85040200237 (Scopus ID)
Note

QC 20180115

Available from: 2018-01-15 Created: 2018-01-15 Last updated: 2018-06-25Bibliographically approved
Benyahia Erdal, N., Adolfsson, K. H. & Hakkarainen, M. (2016). Silicone-hydrogel bandage lenses used in conjunction with pharmaceutical eye drops: An uptake and release study. Abstract of Papers of the American Chemical Society, 251
Open this publication in new window or tab >>Silicone-hydrogel bandage lenses used in conjunction with pharmaceutical eye drops: An uptake and release study
2016 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 251Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2016
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-242675 (URN)000431905706182 ()
Note

QC 20190222

Available from: 2019-02-22 Created: 2019-02-22 Last updated: 2019-02-22Bibliographically approved
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