Synthesis of a novel liquid crystal rod–coil star block copolymer consisting of poly(methyl methacrylate) and poly{2,5‐bis[(4‐methoxy‐phenyl)oxycarbonyl] styrene} via atom transfer radical polymerization

Abstract

A bromine capped star‐shaped poly(methyl methacrylate) (S‐PMMA‐Br) was synthesized with CuBr/sparteine/PT‐Br as a catalyst and initiator to polymerize methyl methacrylate (MMA) according to atom transfer radical polymerization (ATRP). Then, with S‐PMMA‐Br as a macroinitiator, a series of new liquid crystal rod–coil star block copolymers with different molecular weights and low polydispersity were obtained by this method. The block architecture {coil‐conformation of the MMA segment and rigid‐rod conformation of 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl] styrene segment} of the four‐armed rod–coil star block copolymers were characterized by 1H NMR. The liquid‐crystalline behavior of these copolymers was studied by differential scanning calorimetry and polarized optical microscopy. We found that the liquid‐crystalline behavior depends on the molecular weight of the rigid segment; only the four‐armed rod–coil star block copolymers with each arm's Mn,GPC of the rigid block beyond 0.91 × 104 g/mol could form liquid‐crystalline phases above the glass‐transition temperature of the rigid block. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 733–741, 2005

Synthesis and characterization of polycholesteryl methacrylate–polyhydroxyethyl methyacrylate block copolymers

“…Several approaches have been developed to synthesize rod‐coil block copolymers with tailored functionality, amphiphilicity, and composition. These methods include controlled radical polymerizations such as atom transfer radical polymerization (ATRP) and reversible addition fragmentation transfer (RAFT), living anionic, living cationic polymerization, and metal‐catalyzed coordination polymerization 8–14…”

Synthesis and properties of liquid‐ crystalline triblock copolymers by ATRP, having electron‐transporting thiadiazole unit

“…Atom‐transfer radical polymerization (ATRP) is a simple, convenient and useful polymerization technique for the preparation of polymers having controlled molecular structures and narrow molecular weight distributions 1–5. So far, a large body of research concerning polymers such as block copolymers, hyperbranched polymers and dendrimers with various functions produced by the ATRP method has been reported 6–8. Light‐emitting and charge‐ (electron‐ and hole‐) transporting polymers have attracted much attention as organic materials for electroluminescent (EL) devices 9, 10.…”

Self‐assembly of star‐shaped polystyrene‐block‐polypeptide copolymers synthesized by the combination of atom transfer radical polymerization and ring‐opening living polymerization of α‐amino acid‐N‐carboxyanhydrides

“…Diblock copolymers having rod–coil structures represent an attractive class of building blocks for the preparation of nanostructured materials because of their self‐assembling nature that forms phase‐separated structures in the range of several nanometers 23–25. As a result of the self‐assembling behavior and conformational asymmetry between the rod and coil segments, this class of block copolymers possesses relatively high Flory–Huggins parameters in comparison with rod–rod block copolymers 26.…”