Liquid crystalline side chain methacrylic azo containing polymers

Abstract

This paper describes the synthesis and characterisation of methacrylic liquid crystalline side chain polymer containing azo group, with (PM6OAn) and without (PM6An) hydroxyl group. The characterisation was done by using a polarised light microscope (PLM), differential thermal analysis (DTA), and X-ray diffractometry. All compounds developed bilayer smectic phase, with a certain degree of interdigitation between the layers. Poly[{3-hydroxy-4-[(E)-(4-octyloxyphenyl)diazenyl]phenoxy}hexyl]-2-methyl-prop-2-enoate (PM6OA8) exhibits a smectic A phase, whereas the other polymers show a SmC phase. Pyroelectric investigations show only an antiferroelectric behaviour for poly [{3-hydroxy-4-[(E)-(4-dodecyloxyphenyl)diazenyl]phenoxy}hexyl]-2-methylprop-2-enoate (PM6OA12) and a paraelectric behaviour for PM6OA8, poly[{4-[(E)-(4-dodecyloxyphenyl)diazenyl]phenoxy}hexyl]-2-methylprop-2-enoate (PM6A12) and poly [{4-[(E)-(4-octyloxyphenyl) diazenyl] phenoxy} hexyl]-2-methylprop-2-enoate (PM6A8). Finally, the E-Z photoisomerisation of the chromophores in solution was probed to exist in PM6A12 and PM6A8.

Keywords:

• azo aromatic polymers
• bilayer smectic phase
• photoisomerisation

Acknowledgements

C.M. González-Henríquez acknowledges a Scholarship from Conicyt and E.A. Soto-Bustamante is grateful for financial support from Project FONDECYT 2007 Nr. 1071059 and Merck Chile S.A.