Werner Schlemmer

Dr. Werner Schlemmer

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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 August 2021 in Carbohydrate Polymers
Verified
Journal Article
Open access
WSWerner Schlemmer
Werner Schlemmer
JSJulian Selinger
Julian Selinger
MHMathias Andreas Hobisch
Mathias Andreas Hobisch
Stefan SpirkStefan Spirk
Stefan Spirk
The increasing amount of electric vehicles on our streets as well as the need to store surplus energy from renewable sources such as wind, solar and tidal parks, has brought small and large scale batteries into the focus of academic and industrial research. While there has been huge progress in performance and cost reduction in the past years, batteries and their components still face several environmental issues including safety, toxicity, recycling and sustainability. In this review, we address these challenges by showcasing the potential of polysaccharide-based compounds and materials used in batteries. This particularly involves their use as electrode binders, separators and gel/solid polymer electrolytes. The review contains a historical section on the different battery technologies, considerations about safety on batteries and requirements of polysaccharide components to be used in different types of battery technologies. The last sections cover opportunities for polysaccharides as well as obstacles that prevent their wider use in battery industry.

1 February 2021 in Carbohydrate Polymers
Verified
Journal Article
Open access
LSLeo Svenningsson
Leo Svenningsson
JBJenny Bengtsson
Jenny Bengtsson
KJKerstin Jedvert
Kerstin Jedvert
WSWerner Schlemmer
Werner Schlemmer
HTHans Theliander
Hans Theliander
LELars Evenäs
Lars Evenäs
Cellulose-lignin composite carbon fibers have shown to be a potential environmentally benign alternative to the traditional polyacrylonitrile precursor. With the associated cost reduction, cellulose-lignin carbon fibers are an attractive light-weight material for, e.g. wind power and automobile manufacturing. The carbon fiber tenacity, tensile modulus and creep resistance is in part determined by the carbon content and the molecular orientation distribution of the precursor. This work disassociates the molecular orientation of different components in cellulose-lignin composite fibers using rotor-synchronized solid-state nuclear magnetic resonance spectroscopy and X-ray scattering. Our results show that lignin is completely disordered, in a mechanically stretched cellulose-lignin composite fiber, while the cellulose is ordered. In contrast, the native spruce wood raw material displays both oriented lignin and cellulose. The current processes for fabricating a cellulose-lignin composite fiber cannot regain the oriented lignin as observed from the native wood.

29 November 2018 in Materials
Verified
Journal Article
Open access
PDF file
WSWerner Schlemmer
Werner Schlemmer
WFWolfgang Fischer
Wolfgang Fischer
AZArmin Zankel
Armin Zankel
Tomislava Vukušić PavičićTomislava Vukušić Pavičić
Tomislava Vukušić Pavičić
GFGregor Filipič
Gregor Filipič
Nikša KrstulovićNikša Krstulović
Nikša Krstulović
For this study, a paper impregnated with silver nanoparticles (AgNPs) was prepared. To prepare the substrates, aqueous suspensions of pulp fines, a side product from the paper production, were mixed with AgNP suspensions. The nanoparticle (NP) synthesis was then carried out via laser ablation of pure Ag in water. After the sheet formation process, the leaching of the AgNPs was determined to be low while the sheets exhibited antimicrobial activity toward Escherichia coli (E. coli).

30 November 2018 in Materials
Verified
Journal Article
Open access
PDF file
WSWerner Schlemmer
Werner Schlemmer
AZArmin Zankel
Armin Zankel
KNKatrin Niegelhell
Katrin Niegelhell
MHMathias Hobisch
Mathias Hobisch
MSMichael Süssenbacher
Michael Süssenbacher
Stefan SpirkStefan Spirk
Stefan Spirk
This study investigates flexible (polyamide 6.6 PA-6.6, polyethylene terephthalate PET, Cu, Al, and Ni foils) and, for comparison, stiff substrates (silicon wafers and glass) differing in, for example, in surface free energy and surface roughness and their ability to host cellulose-based thin films. Trimethylsilyl cellulose (TMSC), a hydrophobic acid-labile cellulose derivative, was deposited on these substrates and subjected to spin coating. For all the synthetic polymer and metal substrates, rather homogenous films were obtained, where the thickness and the roughness of the films correlated with the substrate roughness and its surface free energy. A particular case was the TMSC layer on the copper foil, which exhibited superhydrophobicity caused by the microstructuring of the copper substrate. After the investigation of TMSC film formation, the conversion to cellulose using acidic vapors of HCl was attempted. While for the polymer foils, as well as for glass and silicon, rather homogenous and smooth cellulose films were obtained, for the metal foils, there is a competing reaction between the formation of metal chlorides and the generation of cellulose. We observed particles corresponding to the metal chlorides, while we could not detect any cellulose thin films after HCl treatment of the metal foils as proven by cross-section imaging using scanning electron microscopy (SEM).

18 December 2020 in Polymers
Verified
Journal Article
Open access
PDF file
PVPilar Vilaró
Pilar Vilaró
CSCarina Sampl
Carina Sampl
GTGundula Teichert
Gundula Teichert
WSWerner Schlemmer
Werner Schlemmer
MHMathias Hobisch
Mathias Hobisch
Stefan SpirkStefan Spirk
Stefan Spirk
Interactions of biomolecules at interfaces are important for a variety of physiological processes. Among these, interactions of lectins with monosaccharides have been investigated extensively in the past, while polysaccharide-lectin interactions have scarcely been investigated. Here, we explore the adsorption of galactomannans (GM) extracted from Prosopis affinis on cellulose thin films determined by a combination of multi-parameter surface plasmon resonance spectroscopy (MP-SPR) and atomic force microscopy (AFM). The galactomannan adsorbs spontaneously on the cellulose surfaces forming monolayer type coverage (0.60 ± 0.20 mg·m−2). The interaction of a lectin, Concavalin A (ConA), with these GM rendered cellulose surfaces using MP-SPR has been investigated and the dissociation constant KD (2.1 ± 0.8 × 10−8 M) was determined in a range from 3.4 to 27.3 nM. The experiments revealed that the galactose side chains as well as the mannose reducing end of the GM are weakly interacting with the active sites of the lectins, whereas these interactions are potentially amplified by hydrophobic effects between the non-ionic GM and the lectins, thereby leading to an irreversible adsorption.

26 October 2021 in ACS Omega
Verified
Journal Article
Open access
JLJussi Lahti
Jussi Lahti
RPRoman Poschner
Roman Poschner
WSWerner Schlemmer
Werner Schlemmer
AHAndrea Hochegger
Andrea Hochegger
ELErich Leitner
Erich Leitner
UHUlrich Hirn
Ulrich Hirn
We present how harmful different wood extractives carried over to paper mill with unbleached softwood Kraft pulp are for the strength of packaging papers and boards. The investigations were done by simulating industrial papermaking conditions in laboratory-scale trials for handsheet production. It was found that fatty acids are the most relevant compounds in the carryover pitch extractives (CPEs), as they readily interfere in fiber–fiber bonding strength, control the properties of CPE micelles, and are furthermore the most abundant compounds. Addition of cationic starch improved strength and evened out the strength differences of handsheets with different CPE compounds. Oleic acid (unsaturated fatty acid) was an exception, as it was above average harmful for paper strength without cationic starch and also heavily impaired the functioning of cationic starch. As a whole, these findings demonstrate that fatty acids, especially unsaturated ones, are the most relevant CPE compounds contributing to the reduced efficiency of cationic starch and decreased strength of unbleached softwood Kraft paper. This makes the cleaning of process waters by precipitating CPEs on the pulp fibers harmful for paper strength.