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This article is part of the Research Topic

Biopolymer Thin Films and Coatings

Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Chem. | doi: 10.3389/fchem.2019.00239

Design of friction, morphology, wetting and protein affinity by cellulose blend thin film composition

 Caterina Czibula1, 2, Gundula Teichert3,  Maximilian Nau4, Mathias Hobisch3, Chonnipa Palasingh5, Markus Biesalski4,  Stefan Spirk2, 3, Christian Teichert1* and  Tiina Nypelö5, 6*
  • 1Institute of Physics, University of Leoben, Austria
  • 2Christian Doppler Laboratory for Fiber Swelling and Paper Performance, Graz University of Technology, Austria
  • 3Institute of Paper, Pulp and Fiber Technology, Graz University of Technology, Austria
  • 4Macromolecular Chemistry and Paper Chemistry, Department of Chemistry, Darmstadt University of Technology, Germany
  • 5Chalmers University of Technology, Sweden
  • 6Wallenberg Wood Science Center(WWSC), Chalmers University of Technology, Sweden

Cellulose derivate phase separation in thin films was applied to generate patterned films with distinct surface morphology. Patterned polymer thin films are utilized in electronics, optics, and biotechnology but films based on bio-polymers are scarce. Film formation, roughness, wetting, and patterning are often investigated when it comes to characterization of the films. Frictional properties, on the other hand, have not been studied extensively. We extend the fundamental understanding of spin coated complex cellulose blend films via revealing their surface friction using Friction Force Microscopy (FFM). Two cellulose derivatives were transformed into two-phase blend films with one phase comprising trimethyl silyl cellulose (TMSC) regenerated to cellulose with hydroxyl groups exposed to the film surface. Adjusting the volume fraction of the spin coating solution resulted in variation of the surface fraction with the other, hydroxypropylcellulose stearate (HPCE) phase. The film morphology confirmed lateral and vertical separation and was translated into effective surface fraction. Phase separation as well as regeneration contributed to the surface morphology resulting in roughness variation of the blend films from 1.1 to 20.5 nm depending on the film composition. Friction analysis was successfully established, and then revealed that the friction coefficient of the films could be tuned and the blend films exhibited lowered friction force coefficient compared to the single-component films. Protein affinity of the films was investigated with bovine serum albumin (BSA) and depended mainly on the surface free energy (SFE) while no direct correlation with roughness or friction was found. BSA adsorption on film formed with 1:1 spinning solution volume ratio was an outlier and exhibited unexpected minimum in adsorption.

Keywords: Blend films, Spinodal decomposition, Cellulose, Friction, protein adsorption, Adhesion

Received: 28 Jan 2019; Accepted: 26 Mar 2019.

Edited by:

Giuseppe Mensitieri, University of Naples Federico II, Italy

Reviewed by:

Ram Gupta, Pittsburg State University, United States
Artur J. Valente, University of Coimbra, Portugal  

Copyright: © 2019 Czibula, Teichert, Nau, Hobisch, Palasingh, Biesalski, Spirk, Teichert and Nypelö. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Christian Teichert, Institute of Physics, University of Leoben, Leoben, Austria, christian.teichert@unileoben.ac.at
Dr. Tiina Nypelö, Chalmers University of Technology, Göteborg, 412 96, Vastra Gotaland County, Sweden, tiina.nypelo@chalmers.se