A series of new diblock copolymers bearing rigid liquid crystal cholesterol grafts denoted as PHEMAChol-b-PBLG were designed and sucessfully prepared via a combination of reversible addition-fragmentation chain transfer polymerization (RAFT)
ring opening polymerization (ROP) and click chemistry
and their molecular structures were further characterized by NMR
FTIR
GPC and static light scattering (SLS).Then
liquid crystal (LC) phase structures and their transitions as well as thermal stabilities were characterized by differential scanning calorimetry (DSC)
polarized optical microscopy (POM) and thermo gravimetric analysis (TGA)
and secondary structures of the PBLG blocks were analyzed by FTIR
X-ray diffraction (XRD) and solid-state 13C CP/MAS NMR techniques.Moreover
their secondary molecular structures in THF were analyzed by circular dichroism spectrum (CD)
and self-aggregate morphologies in THF/DMF mixed solution were investigated by transmission electron microscopy (TEM).The results demonstrated predominant -helix secondary structures of PBLG blocks for the resulted PHEMAChol-b-PBLG in solid state
and the longer PBLG blocks led to more well-defined -helix structures
and PBLG secondary structures in solution could be tuned by their block lengths and the TFA volume fraction.