Preparation of an amphiphilic diblock copolymer composed of polystyrene and hydrophilic alternating copolymer blocks

Abstract

Generally, conventional free-radical polymerization of an allyl monomer affords low-molecular-weight oligomers. However, since the allyl monomer can form a charge transfer complex with maleic anhydride (MA), in which the former acts as an electron donor and the latter acts as an acceptor, relatively high-molecular-weight alternating copolymers can be obtained via copolymerization of an allyl monomer and MA. In this study, hydrophilic alternating copolymers (P(11EO/MA)m) of methoxy poly(ethylene glycol) allyl ether (11EO) and MA were prepared via reversible addition–fragmentation chain transfer (RAFT)-controlled radical polymerization. The alternating nature of the polymers was confirmed by the consumption of both monomers during polymerization. The MA units in P(11EO/MA)m were hydrolyzed to prepare pendant carboxylic acid group-containing polymers (P(11EO/MH)m). Furthermore, an amphiphilic diblock copolymer (P(11EO/MH)m-PSn) was prepared via RAFT copolymerization of styrene monomer using P(11EO/MH)m as a macro-chain transfer agent. The association behavior of P(11EO/MH)m-PSn in water was also investigated. Hydrophilic alternating copolymers (P(11EO/MA)m) of methoxy poly(ethylene glycol) allyl ether (11EO) and maleic anhydride (MA) were prepared via controlled radical polymerization. The MA units in P(11EO/MA)m were hydrolyzed to prepare pendant carboxylic acid group-containing polymers (P(11EO/MH)m). Furthermore, an amphiphilic diblock copolymer (P(11EO/MH)m-PSn) was prepared via block copolymerization of styrene using P(11EO/MH)m as a macro-chain transfer agent. The association behavior of P(11EO/MH)m-PSn in water was also investigated.