Modification of silk fabric with 4-nonafluorobutyl-4′-azobenzene by grafting polymerization and its reversible hydrophobicity-hydrophilicity response

The silk fabric was modified with 4-nonafluorobutyl-4'-azobenzol acrylate (NFBA) through atom transfer radical polymerization (ATRP). FT-IR and XPS were used to confirm the structures of the silk fabric before and after modification. The surface morphology was recorded by SEM and surface property was tested by contact angle (CA). The reversible isomerization of azobenzene on silk was observed by processing with UV and visible alternately. As a result, the reversible hydrophobicity-hydrophilicity transformation on silk fabric was successfully achieved by controlled grafting polymerization via ATRP.