Characterization of Polydimethylsiloxane-block-polystyrene (PDMS-b-PS) Copolymers by Liquid Chromatography at Critical Conditions

In this study, liquid chromatography at critical conditions (LCCC) is used to determine the block lengths and molar masses of polydimethylsiloxane-block-polystyrene copolymers synthesized via atom transfer radical polymerization (ATRP) techniques. In addition, the analysis allows for the determination of the presence of homopolymers in the samples. LCCC at the critical point of polydimethylsiloxane (PDMS) on a reversed phase column allows for the determination of PDMS homopolymer and the length of the polystyrene (PS) block in the block copolymer which elutes in the size exclusion chromatography (SEC) regime under these conditions. The PDMS block length and PS homopolymer can be obtained under normal phase conditions. The results of LCCC are compared with data from conventional SEC.