Chiral expression in conjugated helical block copolymers

Abstract

The organizational behaviour of block copolymers consisting of two helical blocks with opposite chiral expression is investigated. Two series of helical block copolymers are made with blocks with opposite chiral expression. In the first series, two enantiomers are used for the two different blocks. The length of the different blocks is varied throughout the series and the chiral expression of the block copolymers is measured using CD spectroscopy. It was found that for helical block copolymers consisting of enantiomers, the organizational behaviour of one block is not influenced by the other block. The second series consists of block copolymers with two chemically different blocks, combined in different ratios. It was found that for these polymers there is a clear influence of both blocks on each other's aggregation behaviour. One block can enforce its helical pitch and/or diameter onto the other block.