Temperature- and pH-sensitive diblock copolymers PAANa75-b-PNIPAMm 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 PAANa75-b-
PNIPAM76 as well as spherical crew-out micelles
with a PNIPAM core for PAANa75-b-PNIPAM5110,
as indicated by a ?uorescence probe technique
and TEM. A three-stage model mechanism of
phase transition driven by small molecule salt is proposed.