Homogeneous cellulose thin films by regeneration of cellulose xanthate: properties and characterization

Michael Weißl,Katrin Niegelhell,Armin Zankel,Stefan Spirk,Josef Innerlohinger,David Reishofer

doi:10.1007/s10570-017-1576-3

Abstract

The preparation and characterization of cellulose thin films derived from cellulose xanthate is reported. The films are prepared by depositing alkaline aqueous solutions of cellulose xanthate onto silicon wafers, followed by a spin coating step. Depending on the xanthate concentration used for spin coating, films with 50 and 700 nm thickness are obtained. The cellulose xanthate is converted to cellulose by exposing the films to HCl vapors over a period of 20 min. The conversion is monitored by ATR-IR spectroscopy, which allows for tracking the rupture of C–S and C=S bonds during the regeneration process. The conversion is accompanied by a reduction of the film thickness of ca 40% due to the removal of the bulky xanthate group. The films feature a homogenous, but porous morphology as shown by atomic force microscopy. Further, the films were investigated towards their interaction with Bovine Serum Albumin (BSA) and fibrinogen by means of multi-parameter surface plasmon resonance spectroscopy. Similar as other cellulose thin films BSA adsorption is low while fibrinogen adsorbs to some extent at physiological pH (7.4).

Highlights

The preparation and characterization of cellulose thin films derived from cellulose xanthate is reported
We report our approach to prepare such films starting from different concentrations of cellulose xanthate in aqueous alkaline solutions and their influence on film properties
It turned out that the cellulose xanthate (CX) concentration must be in a range between 0.75 and 4.0 wt% to obtain homogenous films on the different substrates (i.e. Si-wafer, glass slides, gold coated glass slides)

Summary

Introduction

The preparation and characterization of cellulose thin films derived from cellulose xanthate is reported. CX has been first prepared already in the end of the nineteenth century and was since used as a soluble cellulose derivative for the production of regenerated fibers and films. We report our approach to prepare such films starting from different concentrations of cellulose xanthate in aqueous alkaline solutions and their influence on film properties.

Results

Conclusion