Some novel smectic C liquid-crystalline side-chain polymers Polymethacrylates and poly a-chloroacrylates

Novel methacrylate and α-chloroacrylate side-chain polymers in which the mesogenic moieties are based on the 4-n-alkoxyphenyl-4'-(4'-methylhexyloxy) benzoates have been characterized by differential scanning calorimetry, optical microscopy and X-ray diffraction. Polymethacrylates give smectic A phases although the homologue where n = 11 exhibits a smectic C∗-smectic A transition. There is no real evidence for liquid-crystalline properties in the poly-α-chloroacrylates where n = 2 or 6. The poly-α-chloroacrylate for which n = 11 exhibits a layer structure with the side chains orthogonal to the layer planes as in the smectic A phase. However, this smectic phase has a higher order of the molecules within the layers; the chlorine atoms do impose a local ordering of the mesogenic side groups.