Biomacrocyclic side-chain liquid crystalline polymers bearing cholesterol mesogens: facile synthesis and topological effect studyElectronic supplementary information (ESI) available. See DOI: 10.1039/c5py01003a

Herein we describe the rational design and facile synthesis of biomacrocyclic side-chain liquid crystalline polymers bearing cholesterol mesogens with three different length methylene spacers ( m = 2, 6, 11) via the combination of reversible addition-fragmentation chain transfer (RAFT) polymerization with Cu( i )-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry. The successful cyclization was confirmed by comprehensive characterization including size-exclusion chromatography (SEC), triple detection size-exclusion chromatography (TD-SEC), Fourier transform infrared (FT-IR) and 1 H NMR spectra. Subsequently, the liquid crystalline (LC) phase behaviors of the linear and cyclic polymers were investigated systematically. Both linear and cyclic polymers form the smectic phase and exhibit a similar layer periodicity. However, the cyclic ones exhibit a slightly lower mesophase transition temperature, enthalpy, entropy and smaller textures compared with their linear counterparts. Meanwhile, the smectic C (SmC) phase is preferable in cyclic polymers with a long methylene spacer ( m = 11) compared with that in the linear one. Biomacrocyclic side-chain liquid crystalline polymers bearing cholesterol mesogens with three different length methylene spacers were prepared. Meanwhile, the liquid crystalline phase behaviors were investigated systematically.