Thermoresponsive star-shaped polymer with heteroarm type with methacrylates: preparation by living radical polymerization method and its topological effect

We first designed the thermoresponsive star-shaped polymer with heteroarm structure based on methacrylates by living radical polymerization with Ru catalyst. The lowest critical solution temperature (LCST) of the heteroarm polymer was controlled within the range 26-52 degrees C by changing the initial ratio of diethylene glycol methyl ether methacrylate (DEGMA) and triethylene glycol methyl ether methacrylate (TEGMA) in the copolymerization. The synthesized heteroarm star-shaped polymer consisted of P(DEGMA-stat-TEGMA), with a unit composition of DEGMA : TEGMA = 83 : 17 and LCST of 35 degrees C, and poly(methyl methacrylate) (PMMA), and possessed approximately six arms of P(DEGMA-stat-TEGMA) and approximately two arms of PMMA. This heteroarm star-shaped polymer was insoluble in water. However, the star-shaped polymer-coated surface showed thermoresponsivity, in which the contact angle of the captive bubble changed from 131 +/- 0.6 degrees at 20 degrees C to 126 +/- 1.9 degrees at 40 degrees C. This result indicates that such heteroarm star-shaped polymers can be promising materials for constructing thermoresponsive surfaces using simple coating methods.