The synthesis and solution behaviors of novel amphiphilic block copolymers based on d-galactopyranose and 2-(dimethylamino)ethyl methacrylate

• We report stimuli-responsive AB, ABA and BAB type novel block copolymers.
• First, glyco and tertiary amine methacrylate-based block copolymers were synthesized via ATRP.
• Glycoblocks were then converted to water soluble blocks via deprotection process.
• All block copolymers had thermo-responsive behavior in alkali solutions.
• They formed well-defined core–shell micellar structures at high temperatures (pH > 8).

A series of novel stimuli-responsive AB, ABA, and BAB type block copolymers based on 6-O-methacryloyl-1,2:3,4-di-O-isopropylidene-d-galactopyranose (MAIpGP:A block) and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA: B block) were synthesized via ATRP techniques using ethyl 2-bromoisobutyrate (EBiB) as monofunctional ATRP initiator in the case of diblock copolymer and diethyl meso-2,5-dibromoadipate (DEDBA) as bifunctional ATRP initiator in the case of triblock copolymers. The PMAIpGP blocks of the AB, ABA, and BAB type linear block copolymers were converted to water soluble PMAGP blocks via deprotection process under mild acidic conditions. Both proton NMR and DLS studies demonstrated that block copolymers were temperature-sensitive, whereby the lower critical solution temperature (LCST) of polymers varied with the polymerization degrees of comonomers in the block copolymers. LCST was determined to be between ∼35 °C and 55 °C depending on the type and the comonomer compositions of the block copolymers. It was observed that an increase on the percentage of hydrophilic PMAGP block in block copolymer caused an increase on the LCST value as expected.

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