Biobased Oleyl Glycidyl Ether: Copolymerization with Ethylene Oxide, Postmodification, Thermal Properties, and Micellization Behavior

Abstract

Oleyl glycidyl ether (OlGE) is a highly hydrophobic monomer synthesized from a biobased fatty alcohol and epichlorohydrin. When combined with hydrophilic monomethoxy poly(ethylene glycol) (mPEG) macroinitiators, well-defined, highly amphiphilic AB block copolymers are obtained via anionic ring-opening polymerization (Đ ≤ 1.08). Surprisingly, an investigation of the copolymerization kinetics of OlGE and ethylene oxide revealed an almost ideally random copolymerization (rEO = 1.27, rOlGE = 0.78) despite the significant structural differences. Both statistical and block copolymers were investigated regarding their behavior in aqueous solution. The block copolymers of the type mPEG-b-POlGE featured two distinct melting temperatures (Tms). Besides a melting transition of mPEG, a second Tm is attributed to the crystallization of the cis-alkenyl side chain of the OlGE units. Varying degrees of side chain hydrogenation of the POlGE homopolymer using potassium azodicarboxylate (PADA) allowed for tailoring of the Tm. The thiol-ene click reaction allowed subsequent functionalization. This work not merely highlights the prospect of novel polyether surfactants, it also suggests the potential of biobased long-chain polyethers for the development of drug delivery systems featuring temperature-controlled release.