Controlled assembly of glucuronoxylans onto cellulose fibres

In this study we have shown that cellulose fibres can be coated with regula r micron-sized particles by controlling the assembly process of xylans on t he cellulose surfaces. When cotton linters were exposed to a 5 % water solu tion of xylan from birchwood at 110 degreesC, 2 h, pH 8, the substrates sho wed an increase in weight of approximately 6.5 %, and visualization by AFM revealed regular particles on the fibre surfaces. The surface modification process was optimized using an experimental design where time, temperature, and pH were varied. The experiments showed that the amount of xylan deposi ted on the fibres could be varied from 2 % up to 20 % depending on treatmen t conditions. The temperature and time were the most important parameters, while pH was not important in the investigated region. The morphology of th e deposited xylan layer, as shown by SEM, was dependent on the amount of xy lan on the fibre surfaces. At low yield the fibres were coated with a homog enous layer, while at higher yields (20 %) regular particles of micron size were identified by AFM analysis. The mechanism of this assembly process of xylan on cellulose fibre surfaces is discussed.