Emulsion-induced ordered microporous films using amphiphilic poly(ethylene oxide)-block-poly(n-butyl isocyanate) block copolymers

Well-defined poly(ethylene oxide)-block-poly(n-butyl isocyanate) (PEO-block-PBIC; AB) diblock copolymers were prepared with trichloropentadienyl titanium (IV) (CpTiCl3) catalyst. Ordered microporous films (hexagonal pattern) were constructed by emulsion micelles of A(110)B(230) diblock copolymer (the subscript indicates the degree of polymerization of each block component) formed from CHCl3/H2O/tetrahydrofuran (THF) = 100/5/10 (v/v) solution. The addition of THF promoted uniform micelles in immiscible CHCl3/H2O mixed solvent as well as the effect of phase transfer catalyst. Diblock copolymers formed spherical micelles, consisting of a PEO core and a PBIC corona. At some concentration, interaction between micelles forced a disorder-order transition, resulting in freezing of micelles in some superlattice. Subsequently, the leaving gaps among micelles were filled by PBIC block chains on a corona through the evaporation of organic solvents. At last, water within hydrophilic PEO core was vomited through the film matrix. We also constructed the microporous films using A(110)B(230) diblock copolymer by the current water-assisted method. (C) 2008 Wiley Periodicals, Inc.