Topochemically Controlled Polymerization of a Smectic Liquid Crystalline Diacrylate Monomer

Abstract

In the past two decades, the field of polymerization in the mesomorphic phase has drawn the attention of an increasing number of both chemists and physicists due to the possibility of using a liquid crystalline matrix to control both the polymerization kinetics and the structure of resulting polymers (topochemical control). Macromolecules possessing unique chemical and physical characteristics can be obtained this way. The combination of local molecular orientation and molecular mobility exhibited by mesophases is considered to be of prime importance in achieving both kinds of control. Most of the systems studied so far concern only thermally initiated polymerization of mono-functional monomers in the nematic phase; both in bulk and in nematic media (or solvents). Generally no real enhancement of polymerization rate and no substantial structural difference of the resulting polymers were observed when compared with polymerization in isotropic state.1, 2, 3 This is probably due to the fact that there is no marked structural difference between the isotropic liquid and nematic liquid crystal schematically illustrated in Figure 1. Both of them lack long range and even medium range positional correlation between the molecules, which in our view is necessary to attain both kinetic and structural control during polymerization.