Synthesis and surface properties of amphiphilic fluorine-containing diblock copolymers

Amphiphilic diblock copolymers (DCs) of 2,3,4,5,6-pentafluorostyrene (PFS) and 2-hydroxyethyl methacrylate (HEMA) of different composition and molecular weights were prepared by two-step reversible addition-fragmentation chain transfer (RAFT) polymerization and first used for preparation of superhydrophobic coatings for cotton/polyester fabrics. The transition from hydrophobic to superhydrophobic coatings is controlled by the ratio between poly(2,3,4,5,6-pentafluorostyrene) (PPFS) block and poly(2-hydroxyethyl methacrylate) (PHEMA) block lengths (P-n(PFS)/P-n(HEMA)). The increase inP(n)(PFS)/P(n)(HEMA)is accompanied by a significant increase in water (theta(H)(O)(2)) and diiodomethane (theta(CH)(I)(2)(2)) contact angles, which reach the plateau atP(n)(PFS)/P-n(HEMA)= 3.5 and remains almost constant up toP(n)(PFS)/P-n(HEMA)= 6.2. Surface modification of the cotton/polyester fabric with the DC havingP(n)(PFS)/P-n(HEMA)= 6.2 produced superhydrophobic surface with theta(H)(O)(2)= 158 +/- 4 degrees and contact angle hysteresis CAH = 5 +/- 2 degrees, and theta(CH)(I)(2)(2)= 107 +/- 3 degrees.