Self‐assembling in a living supramolecular linear nematic polymer‐like system

Abstract

Self‐assembling in a linear supramolecular liquid crystalline (LC) polymer based on 4,4′‐bipyridine and bis‐(4‐carboxyphenyloxycarbonyl)‐heptanoate was studied by IR spectroscopy and optical microscopy. Although just a simple single hydrogen bond is required for the formation of a polymer chain, the reversibility of the hydrogen bonding forces the supramolecular macromolecule to behave under specific conditions similar to a mixture composed of two partly immiscible low molecular weight materials rather than as a polymer. An analytical description indicates that nematic droplets form two overlapping thermodynamically optimised statistical ensembles all across the phase transition in the linear supramolecular LC polymer studied. The kinetics of the nematic nucleus growth in the melted polymer was also studied. The number of generated nematic droplets oscillates with time. Two regimes of the growth kinetics were recognised: (i) nucleation and nucleus growth and (ii) nucleus coarsening, i.e. Ostwald ripening.

Keywords:

• self‐assembling
• liquid crystalline polymer
• hydrogen bonding
• nematic nucleus growth
• growth kinetics

Acknowledgement

Financial support from the Russian Foundation for Basic Research (grant 06‐08‐00195) is gratefully acknowledged.