SUB-MICROMETER STRUCTURED TEXTILE COATINGS GENERATED FROM CELLULOSE BASED POLYMER BLENDS *

In order to provide coated textiles with a hydrophobic and self-cleaning surface attempts were made to create structures similar to lotus leaves by generating sphere-like structures using phase separation of cellulose derivatives/polyacrylonitrile blend solutions. Morphology of the so formed structures depends on the coagulation conditions. Resulting dimensions of this spherical structures range from 200 nm to 3,000 nm and are influenced by the cellulose derivative substituent, the polymer ratio and the coagulation medium and temperature. In general, blends with cellulose acetate and propionate form smaller spheres than those formed from cellulose carbamate. The polymer blend solutions qualify for coating woven fabrics, particularly for polyamide fibre fabrics. A well-formed surface structure was obtained from CA/PAN blends. The hydrophobicity was enhanced by either adding a fluorocarbon to the coating compound or finishing with a fluoroalkyl silane. Using the last one a surface energy of minimum 4 mN/m could be achieved.