A DSC-STUDY OF THE CHARGE-TRANSFER COMPLEXATION OF DONOR POLY(3,6-CARBOXYMETHYLENE)S

The complexation behaviour of donor poly(3,6-carbazolylmethylene)s wit h fluorinated and/or nonfluorinated tapered tails and of their low mol ecular weight model compounds with the corresponding crystalline low m olecular 3,5-dinitrobenzoic acid accepters has been investigated by DS C. Whereas the blends resulted by charge-transfer (CT) complexation of the amorphous donor polymer containing aliphatic tapered tails with t he corresponding low molecular weight acceptor are also amorphous, the CT-complexed blends of the donor liquid crystalline polymer containin g the perfluorinated tapered tails with the respective low molecular a cceptor maintain the mesophasic character up to a donor/acceptor ratio 1:1. Selective CT complexation of only the fluorinated sites of an am orphous donor copolymer containing randomly distributed both the fluor inated and aliphatic tapered tails in 1:1 proportion with the respecti ve fluorinated 3,5-dinitrobenzoic acid acceptor induces by regioselect ive self-organization a liquid crystalline phase in the copolymer blen d. Complexation of the nonfluorinated sites of the amorphous donor cop olymer by the respective nonfluorinated 3,5-dinitrobenzoic acid accept or, on the contrary, results in an amorphous blend. This provides a si mple model of a transcriptase molecule which by regioselective binding to a DNS molecule induces a conformation change in the main chain.