Self-assembly of azobenzene based side-chain liquid crystalline polymer and n-alkyloxybenzoic acids

KUMARASAMY GAYATHRI, SUBRAMANIAN BALAMURUGAN and PALANINATHAN KANNAN*

Department of Chemistry, Anna University, Chennai 600 025, India

*Corresponding author. E-mail: pakannan@annauniv.edu

MS received 11 September 2010; revised 4 January 2011; accepted 28 February 2011

Abstract. Liquid crystalline pendant polymeric complexes have been obtained by supramolecular assembly of two mesogenic components namely, poly[4-(10-acryloyloxydecyloxy)-4¢- phenylazobenzonitrile] (P10) and 4-alkyloxybenzoic acids (A7–A12). Hydrogen bond formed between carboxylic acid and cyano moiety served as molecular bridge. The polymeric complexes acquitted as undivided liquid crystalline properties exhibited stable and enantiotropic mesophases. The precursor, monomer and polymer were analysed by ¹H-NMR and ¹³C-NMR spectroscopy. The hydrogen bonding interaction in polymer complexes (P10-A7 to P10-A12) was investigated by FT-IR spectroscopy. The thermal behaviours and textural analysis were studied by differential scanning calorimetry and polarized optical microscopy respectively.

Graphical Abstract. Liquid crystalline pendant polymeric complexes have been obtained by supramolecular assembly of two mesogenic components namely, poly[4-(10-acryloyloxydecyloxy)-4¢-phenylazobenzonitrile] (P10) and 4-alkyloxybenzoic acids (A7–A12). Hydrogen bond formed between carboxylic acid and cyano moiety served as molecular bridge. The polymeric complexes exhibited liquidcrystalline properties with stable and enantiotropic mesophases.

Keywords. Self-assembly; H-bonding; liquid crystals; nematic phase; smectic-A phase.