Model films of cellulose : I. Method development and initial results

• This report presents a new method for the preparation of thin cellulose films. NMMO (N- methylmorpholine- N-oxide) was used to dissolve cellulose and addition of DMSO (dimethyl sulfoxide) was used to control viscosity of the cellulose solution. A thin layer of the cellulose solution is spin- coated onto a silicon oxide wafer and the cellulose is precipitated in deionised water. The cellulose film is anchored onto the silicon oxide wafer by a saturated polymer layer. Among many different polymers tested, PVAm (polyvinylamine) and G- PAM (glyoxalated- polyacrylamide) worked well. The preparation of cellulose model films described in this paper resulted in films with thicknesses in the range 20- 270 nm and the thickness can be controlled by altering the concentration of cellulose solution by addition of different amounts of DMSO. The films were cleaned in deionised water and were found to be free from solvents by ESCA analysis and contact angle measurements. The molecular weight distribution of the cellulose surface material shows that there is only minor breakdown of the cellulose chains, mainly by cleavage of the longest molecular mass fraction and without creation of low molecular mass oligomers of glucose.

Keyword

dissolving pulps

microscopy

models

spinning

surface

adsorption

reversibility

kinetics

Publication and Content Type

ref (subject category)

art (subject category)