Transitional Process of Ploy(N-isopropylacrylamide) in Deuterated Solution

The fast phase-transitional process of ploy(N-isopropylacrylamide) (PNIPAM) in deuterated solution was studied by laser induced temperature jump technique combined with time-resolved mid-infrared absorbance difference spectroscopy on nanosecond level. The multi-peaks of amide I0 band of PNIPAM among the energy range of 1565-1700 cm^-1 was experimentally resolved to three groups (i, ii, iii) for the first time, while the distinct three-stage procedure in the phase transitional process of long-chain PNIPAM was observed firstly too. Furthermore, proper assignments were also made for the three group peaks in amide I′band and the three steps in the kinetics process of long-chain PNIPAM.