New thermally responsive fluorescent polymers conjugated with poly (N- isopropylacrylamide)(polyNIPA) have been synthesized. A nonionic water-soluble poly (phenylene-ethynylene)(PPE) was end-capped with a di-tert-butylnitroxide derivative, and subsequent nitroxide-mediated radical polymerization of NIPA afforded PPE-polyNIPA block copolymers. These copolymers phase-separate from aqueous solutions upon heating, ...