Mobility of mesogenic side-chains in liquid crystalline polymers based on the Baylis-Hillman reaction

The hydrodynamic and electro-optical (Kerr effect) properties of two side-c hain liquid crystalline (SCLC) polymers have been investigated in benzene a nd chloroform solution. The polymers are unique in structure and have been prepared using the Baylis-Hillman methodology. The polymers contain (a) a p olar group (CN or COCH3) along the polymer backbone and (b) a hydroxyl grou p on the spacer group which is adjacent to the point of attachment of the s pacer/mesogenic side groups to the polymer backbone. Molecular dimensions a nd the Kerr constants were determined for two SCLC polymers and for three l ow molar mass materials, the n-alkoxycyanobiphenyIs (nOCB), which are struc turally similar to the side chain used in the SCLC polymers. These results are discussed in relation to the chemical structure and dipole moment of th e monomer unit. Dielectric and electro-optical properties of the SCLC polym er containing the -CN group along the polymer backbone were found to be sim ilar to the properties of the nOCB compounds. The difference in the mesogen ic side-chain mobility of the polymers was related to the dipole-dipole int eractions of the polar groups along the polymer backbone.