Synthesis of star polymer by atom transfer radical polymerization with resorcinol-core multifunctional initiator: The construction of nanocapsule via hydrolysis and olefin metathesis reaction of the obtained star polymer

Abstract

Olefin group-carrying styrene, 1-but-3-enyl-4-vinylbenznene (BVB), was polymerized via atom transfer radical polymerization (ATRP) initiated from C-methylcalix [4]resorcinarene-based multifunctional initiator (CRA-bib) at low conversion to produce star polymer [poly(BVB)] with narrow molecular weight distribution (Mw/Mn < 1.35). The copolymerization of styrene (St) with poly(BVB) (Mn = 11,000, Mw/Mn = 1.23) as a macroinitiator afforded star block copolymer [poly(BVB-b-St)] with Mn = 35,000 and Mw/Mn = 1.44. The BVB layer of poly(BVB-b-St), located between the St shell and the CRA core, was crosslinked by olefin metathesis reaction of olefin groups o the BVB moieties. The removal of the CRA core of the crosslinked poly(BVB-b-St) by hydrolysis using KOH as a base gave polymeric hollow sphere [poly(cored crossBVB-b-St)] with good solubility in organic solvents. The morphological structure of the poly(cored crossBVB-b-St) showed spherical aggregates in THF by scanning electron microscopy (SEM). Furthermore, the nanocapsule structure of poly(cored crossBVB-b-St) with hollow spheres was found to be observed by transmission electron microscopy (TEM). © 2008 Wiley Periodicals, Inc.