Synthesis And Thermoresponsive Property Of End-Functionalized Poly(N-isopropylacrylamide) With Cholesteryl Group

End-functionalized poly(N-isopropylacrylamide)(PNIPAM) with the Cholesteryl group was achieved by atom transfer radical polymerization (ATRP) us using 2–chloropropionate Cholesteryl as initiator and CuBr/1,1,4,7,10,10-hexamethyl-tri-ethylenetetramine(HMTETA)as a catalytic system. The polymerization was carried out in THF:water 7:1(V/V) mixed solvent at 25℃with nitrogen.The first order kinetic experiments showed that the polymerization was well-controlled. Through IR, NMR spectrums analysis, the cholesteryl group was found at the end chain of PNIPAM. As a result, the end–functionalized polymer was successfully produced, as well as controlled molecular weight and relatively low polydispersity.The article studied the thermoresponsive property of well-defined PNIPAM with end Cholesteryl group.The Lower Critical Solution Temperature( LCST ) of Ch-PNIPAM increased with the molecular weight increasing.Thermoresponsive property of PNIPAM was affected by cholesteryl group, LCST of PNIPAM with end groups decreased.