Living cationic sequential block copolymerization: synthesis and characterization of poly(4-(2-hydroxyethyl)styrene-b-isobutylene-b-4-(2-hydroxyethyl)styrene) triblock copolymers

Abstract

The synthesis of well-defined poly(4-(2-(tert-butyldimethylsiloxy)ethyl)-styrene-b-isobutylene-b-4-(2-(tert-butyldimethylsiloxy)ethyl)styrene)(PTBDMES-b-PIB-b-PTBDMES) triblock copolymers was accomplished by cationic sequential block copolymerization of isobutylene (IB) and 4-(2-(tert-butyldimethylsiloxy)ethyl)styrene (TBDMES) using the capping-tuning technique in a one-pot procedure in methylcyclohexane/CH3Cl at −80 °C. Deprotection of the precursor triblock copolymer with tetrabutylammonium fluoride yielded poly(4-(2-hydroxyethyl)styrene-b-isobutylene-b-4-(2-hydroxyethyl)styrene) (PHOES-b-PIB-b-PHOES), with pendant hydroxyl groups along the hydrophilic backbone chains. FT-IR, NMR confirmed that hydrolysis was complete.