Regenerated Cellulose Substrate Fluorocarbon Film Morphology, Structure And Performance Studies

Regenerated cellulose films were modified by Ar plasmas in the presence of a magnetic field. We used PTFE (99.99%) as the target. Various discharge conditions (target-substrate distances, sputtering power and sputtering pressure) are discussed.The morphology of fluorocarbon films are observed by means of Scanning Electron Microscopy (SEM) and Atom Force Microscopy (AFM), and estimated the deposition rate of fluorocarbon film. From the photos of SEM, we found that the fluorocarbon grains deposited on the Regenerated cellulose films substrates tended to be finer, more uniformly dispersed, more globular and more densely with increasing the target-substrate distances, sputtering power and sputtering pressure. AFM shows that the surface of the films is undulate. Particles grow vertically to the film surface, and then form a taper-like structure. They are complicated islands-like structure. Each island is composed of many nanometer particles.The surface structure of fluorocarbon films varying with target-substrate distances, sputtering power and sputtering pressure was investigated by X-ray photoelectron spectroscopy (XPS). It was found that the F/C ratio of deposited films is very low. It indicates the absence of fluoro on the films surface and the abundance of the unsaturated double bonds. So fluorocarbon films maybe absorb UV light. The F/C of fluorocarbon films increased with the sputtering pressure increased while decreased with the target-substrate distances and sputtering power increased. Use scrape method to obtain the deposited films and use the method of KBr to obtain IR figure of deposited films, has proved part of results XPS analysis.The result of UV-visible absorption measurements indicated:the absorption peak of the fluorocarbon films is single, the maximum absorption peak is at about 300-330 nm. The ultraviolet absorption of fluorocarbon films is increased with the target-substrate distances, sputtering power and sputtering pressure increased. It is because the particles of fluorocarbon become finer, rounder, and more with the target-substrate distances, sputtering power and sputtering pressure increased, these particles enhance the role of ultraviolet light due to scattering.The result of static contact angle measurements indicated:All contact angle values of deposited films are greater than or very close to 90°. The deposited films exhibit the property highly on water-repellent. For fluorocarbon films, the contact angle of fluorocarbon films increased with the sputtering pressure increased while decreased with the target-substrate distances and sputtering power increased.