Well-Defined Dual Light- and Thermo-Responsive Rod-Coil Block Copolymers Containing an Azobenzene, MEO2MA and OEGMA

Changjun Park; Jaewon Heo; Jinhee Lee; Taehyoung Kim; Sang Youl Kim

doi:10.3390/polym12020284

Well-Defined Dual Light- and Thermo-Responsive Rod-Coil Block Copolymers Containing an Azobenzene, MEO₂MA and OEGMA

Polymers (Basel). 2020 Feb 1;12(2):284. doi: 10.3390/polym12020284.

Authors

Changjun Park¹, Jaewon Heo¹, Jinhee Lee¹, Taehyoung Kim¹, Sang Youl Kim¹

Affiliation

¹ Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.

Abstract

Here we report the dual light- and thermo-responsive behavior of well-defined rod-coil block copolymers composed of an azobenzene unit, 2-(2-methoxyethoxy)ethyl methacrylate (MEO₂MA) and oligo(ethylene glycol) methacrylate (OEGMA). Azobenzene-containing rigid rod blocks prepared by chain growth condensation polymerization of the azobenzene containing monomer were used as a macroinitiator of atom transfer radical polymerization (ATRP) after attaching an α-bromoisobutyryl group as an end group. Synthesis of well-defined rod-coil block copolymers with different coil block lengths was achieved by copolymerization of MEO₂MA and OEGMA monomers. The synthesized polymers exhibited amphiphilic properties and polymeric micelles were formed in aqueous solution. The light-responsive behaviors of azobenzene moieties, photoisomerization by irradiation of light, and thermo-responsive behaviors of P(MEO₂MA-co-OEGMA) coil blocks, aggregation by increment of temperature over lower critical solution temperature, were investigated. A dual stimuli-responsive behavior of the rod-coil block copolymers was observed when exposed to light and heat.

Keywords: MEO2MA; OEGMA; azobenzene; controlled polymerization; light-responsive behavior; rod-coil block copolymer; self-assembly; thermo-responsive behavior.

Abstract

Grants and funding