Crystallization and phase behaviors of multicomponent supramolecular complexes through hydrogen-bonding association

Two series of hydrogen-bonded association chain polymers have been prepared by melt mixing of diacids and bispyridyl. Liquid crystallinity and crystallization behavior of the polymers were studied using DSC, polarized microscopy, and X-ray scattering methods. It is shown that these two polymer series exhibit smectic liquid crystallinity and also crystallinity despite their random chain structures. The two polymer series show very different capabilities in forming the smectic and crystalline phases. This is due to their difference in monomer length, which may lead to different crystallization mechanisms. The study indicates that when the random association chain polymers are made of two types of blocks, one of which has nearly twice the length of the other, the corresponding crystallization behavior can be explained by the existence of "length emulation" crystals.