||Poly(n-isopropylacrylamide) (PNiPAAm), which has lower critical solution temperature (LCST) at near the physiological body temperature, has been used for many fields in sensing, drug delivery, tissue engineering, and so one. because cloud point temperature of cancer cell is higher than the physiological body temperature, tumor targeted drug has difficulty to reach tumor cell. To overcome this problem, PNiPAAm-based copolymer has been widely developed. In this study, we synthesized the poly(NiPAAm-co-acrylamide) (PNiPAAm-co-AAm) copolymer and characterized the thermal behavior using infrared spectroscopy and two-dimensional correlation spectroscopy. The details of this study will be discussed in this presentation.