Liquid‐crystalline structure of poly(L‐lysine) containing azobenzene units in the side chain

The structure of poly( L ‐lysine) containing 44% azobenzene units in the side chain was studied by X‐ray diffraction between room temperature and 150°C. The polymer exhibits a mesomorphic structure of the smectic A1 type. In this structure, stable at least until 150°C, each smectic layer of thickness d results from the superposition of two layers: one of thickness d A contains the free lysine side chains, the other of thickness d B contains the azobenzene modified lysine side chains and the polypeptide main chains, that in their planes are arranged as in the “antiparallel” β‐structure classical for polypeptides.