Preparation of porous membranes by selective decomposition of adamantane unit in ABA‐type triblock copolymer

The mechanism of pore formation by selective decomposition of adamantane unit in an ABA‐type triblock copolymer derived from 4,4‐(hexafluoroisopropylidene)diphthalic anhydride‐2,3,5,6‐tetramethyl‐1,4‐phenylenediamine (6FDA‐TeMPD) and poly(2‐methyl‐2‐adamantylmethacrylate) (PMAdMA) was investigated on this basis. This study aims to developing a novel method of material design for high‐precision gas separation membranes and application to electric devices by improving dielectric constant. Scanning electron microscopy images showed that the membrane structure changed considerably after heating; the difference increased with the increase in adamantane content. Interestingly, the internal structure of Block(36 mol%6FDA‐TeMPD/64 mol%PMAdMA) membrane was almost unchanged although its surface structure was changed. These results suggest that the mechanism of formation of porous membrane involves the decomposition of adamantane unit from surface. In addition, more adamantane units inside the membrane were discharged to the surface of the membrane through a path formed by decomposed adamantane units. POLYM. ENG. SCI., 56:1191–1200, 2016. © 2016 Society of Plastics Engineers