聚(異丙基丙烯醯胺)(poly(N-isopropylacrylamide), PNIPAM)是一種具備溫度敏感性的高分子材料，因其優異的生物相容性與在接近人體體溫時可形成水凝膠的獨特性，已被廣泛應用於生物醫學、藥物釋放等領域，但多數研究論文均忽略了其會形成水凝膠的現象。

本研究首先以傾斜試管實驗，找到Tgel及相分離的溫度區間，再藉由量測不同升溫速率下的cloud point線性回歸外插至升溫速率等於零之處可得到相分離binodal溫度，最後使用小角度光散射法研究PNIPAM水溶液及其共溶劑溶液的凝膠及相分離行為，並在溫度區間為Tgel < T < Tb條件下分析所得光散射強度分佈發現有mass-fractal dimension結構其值約為2.0，驗證了macroscopic gel的存在，由於Cahn’s linear theory並不適合用於描述PNIPAM凝膠SD相分離，因此在本研究分別以phase dissolution、time-resolved light scattering (TRLS)兩種方式，研究分析溫度區間在Tgel < T < Tb、T > Ts,gel下小角度光散射實驗圖譜，從其光散射強度分佈的變化，決定出macroscopic gel的SD相分離溫度(Ts,gel)。

PNIPAM is a temperature-sensitive polymer material known for its excellent biocompatibility and its unique ability to form hydrogels near human body temperature. It has been widely applied in fields such as biomedicine and drug delivery. However, most research studies have overlooked the fact that it can form hydrogels.

This study first identified the gelation temperature (Tgel) through a tilting tube experiment. The binodal temperature of phase separation (Tb) was then determined by linearly extrapolating the cloud point measured at different heating rates to a zero heating rate. Subsequently, small-angle light scattering (SALS) was employed to investigate the gelation and phase separation behaviors of PNIPAM aqueous solutions and PNIPAM solutions with cosolvents. Within the temperature range (Tgel < T < Tb), the scattering intensity profiles revealed a mass-fractal dimension of approximately 2.0, confirming the presence of macroscopic gels. Since Cahn’s linear theory is not suitable for describing spinodal decomposition (SD) in PNIPAM gels, this study further analyzed the SALS profiles using two approaches—phase dissolution and time-resolved light scattering (TRLS)—to investigate the system within the temperature ranges Tgel < T < Tb and T > Ts,gel. From the changes in scattering intensity distribution, the spinodal decomposition temperature of the macroscopic gel (Ts,gel) was determined.

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