Salt‐Induced Micelle Behavior of Poly(sodium acrylate)‐block‐Poly(N‐isopropylacrylamide) by ATRP

Abstract Temperature‐ and pH‐sensitive diblock copolymers PAANa 75 ‐ b ‐PNIPAM m are prepared by a combination of reverse and normal ATRP in aqueous solution at room temperature. The block copolymer is also stimuli‐sensitive with respect to salt in the aqueous solution, and forms spherical star‐like micelles with a PNIPAM core and an expanded PAANa shell for PAANa 75 ‐ b ‐PNIPAM 76 as well as spherical crew‐out micelles with a PNIPAM core for PAANa 75 ‐ b ‐PNIPAM 5110 , as indicated by a fluorescence probe technique and TEM. A three‐stage model mechanism of phase transition driven by small molecule salt is proposed. magnified image