Synthesis and characterization of a novel liquid crystalline star‐shaped polymer based on α‐CD core via ATRP

Abstract

Well‐defined side‐chain liquid crystalline star‐shaped polymers were synthesized with a combination of the “core‐first” method and atom transfer radical polymerization (ATRP). Firstly, the functionalized macroinitiator based on the α‐Cyclodextrins (α‐CD) bearing functional bromide groups was synthesized, confirmed by 1H‐NMR, MALDI‐TOF, and FTIR analysis. Secondly, the side‐chain liquid crystalline arms poly[6‐(4‐methoxy‐4‐oxy‐azobenzene) hexyl methacrylate] (PMMAzo) were prepared by ATRP. The characterization of the star polymers were performed with 1H‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermal polarized optical microscopy (POM). It was found that the liquid crystalline behavior of the star polymer α‐CD‐PMMAzon was similar to that of the linear homopolymer. The phase‐transition temperatures from the smectic to nematic phase and from the nematic to isotropic phase increased as the molecular weight increased for most of these samples. All star‐shaped polymers show photoresponsive isomerization under the irradiation with Ultraviolet light. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Non‐covalent interactions of pyrene end‐labeled star poly(ɛ‐caprolactone)s with fullerene

“…Non‐covalent interaction trials were performed according to the literature by mixing 2 mg of fullerene with 30 mg of pyrene‐POSS and star polymers in 10 mL of THF at room temperature for 24 h . The control experiment was performed under identical conditions (in the absence of pyrene‐POSS and star polymers).…”

“…In the first approach, the precursors with reactive terminal groups are coupled to a multi‐functional core via efficient organic reactions like click chemistry reactions. In the second approach, the polymerization is initiated by a multifunctional core to build the arms of the star polymers . Various polymerization methods such as anionic, cationic, controlled radical (reversible addition–fragmentation transfer, atom transfer radical polymerization) can be applied for the construction of star polymers .…”