Synthesis And Thermoresponsive Property Of Well-Defined Poly (N-Isopropylacrylamide) With Pyrenyl End-Group

The living polymerization method such as Atom transfer radical polymerization (ATRP) was performed and optimized using 1 — pyrenyl -2 -chloropropionate as an initiator and CuCl/tris (2-(dimethylamino) ethyl) amine (Me₆TREN) as the catalyst system to afford end-functionalized Poly (N-isopropylacrylamide) PNIPAM with the pyrenyl group at 20℃. The First Order Kinetic Plot for ATRP of NIPAM using la as initiator in DMF/H₂O 13/2(v/v) showed that the polymerization was well -controlled. Through UV-Vis, IR, NMR spectrums analysis, the pyrenyl group was found at the end chain of PNIPAM. As a result, the end -functionalized polymer was successfully produced by the living radical polymerization method, as well as controlled molecular weight and relatively low polydispersity.The article studied the thermoresponsive property of well-defined PNIPAM with end pyrenyl group. The Lower Critical Solution Temperature (LCST) of PNIPAM decreased with the molecular weight increasing, which was just opposite with the polymer without end-functionalized pyrenyl group. Meanwhile, the polymer was done with β - Cyclodextrin (β - CD) , and β - CD formed an inclusion complex with pyrene, which made LCST of Py - PNIPAM increasing.