New polymethylene-b-poly(styrene-co-2-hydroxyethyl methacrylate) and polymethylene-b-poly(styrene-co-2-hydroxyethyl methacrylate)-g-poly(ε-caprolactone)) copolymers: Synthesis, characterization and their application in the fabrication of highly ordered porous films

A series of new polymethylene- b -poly(styrene- co -2-hydroxyethyl methacrylate) (PM- b -P(St- co -HEMA)) and polymethylene- b -poly(styrene- co -2-hydroxyethyl methacrylate- g -poly(ε-caprolactone)) (PM- b -P(St- co -HEMA- g -PCL)) copolymers were successfully synthesized via a strategy combined polyhomologation of ylides, reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP). Firstly, a hydroxyl terminated polymethylene (PM-OH) was obtained via polyhomologation of ylides followed by oxidation. Then, PM-OH was transformed to a macromolecular chain transfer agent (PM-CTA). Subsequently, RAFT copolymerizations of styrene (St) and 2-hydroxyethyl methacrylate (HEMA) were performed using PM-CTA as chain transfer agent, targeting the well-defined PM- b -P(St- co -HEMA) copolymers with controllable molecular weight and narrow molecular weight distribution. Finally, the ring-opening polymerization of ε-caprolactone was carried out using PM- b -P(St- co -HEMA) copolymer as initiator to achieve PM- b -P(St- co -HEMA- g -PCL) copolymer. The molecular weight and chain structure of the obtained copolymers were characterized by gel permeation chromatography (GPC), proton nuclear magnetic resonance ( 1 H NMR) and Fourier Transform Infrared spectroscopy (FTIR). Moreover, the fabrication of highly ordered porous films using the amphiphilic PM- b -P(St- co -HEMA) copolymers via a static breath-figure process was investigated.