Double stimuli-responsive perforated lamellar structure formed by linear ABC triblock terpolymer monoliths

Abstract

Amphiphilic block copolymer (BCP) thick films with stimuli-responsive pores are promising candidates for the manufacturing of next-generation ultrafiltration (UF) membranes since their smart nanochannels facilitates the removal of fouling which is considered as one of the biggest challenges in membrane technology. In this work, a well-defined polystyrene-block-poly(2-vinylpyridine)-block-poly(N-isopropylacrylamide) (PS-b-P2VP-b-PNIPAM) terpolymer was prepared for the first time via reversible addition-fragmentation chain transfer polymerization. The combination of the nonsolvent-induced phase separation process with a solvent vapor annealing treatment was used to produce nanostructured pH- and thermo-double sensitive ABC-type BCP thick films. Here, the NIPS-made PS-b-P2VP-b-PNIPAM thick film, comprising a microporous spinodal-type network substructure, topped by a dense thin layer of poorly defined nanopores is transformed into a monolith entirely composed of a well-ordered perforated lamellar (PL) phase upon exposure to a chloroform vapor during 6 h. Such kind of PL-structured monoliths, showing a permeance value as high as 18 L h−1 m−2 bar−1 at 46°C and pH = 7 with an excellent temperature cyclability, are highly desired to manufacture smart separation-based UF materials able to transit their pore state from hydrophilic to hydrophobic (and vice versa), thereby leading to much more efficient detachment of foulants during the cleaning process.