聚(異丙基丙烯醯胺)(PNIPAM)水溶液具有lower critical solution temperature (LCST)的相變化行為，即當水溶液溫度低於相分離溫度時為均勻的一相，而當高於相分離溫度時，PNIPAM分子鏈表現出疏水性，形成相分離，其LCST接近室溫。目前有文獻提到中子散射(SANS)，可鑑定PNIPAM水溶液之相分離，此文獻表示， PNIPAM水溶液的對比條件不利，因此要使用小角度X光散射(SAXS)進行此實驗非常具有挑戰性，此一說明引起了我們研究的興趣。

本研究以去離子水為溶劑在低於相分離溫度下配製PNIPAM溶液。藉由流變儀動態測試，量測不同濃度溶液在低於相分離溫度下 、 與關係圖，進而得到Tb、Ts、Tgel、Tonset, G'、Tonset, G'，並進行比較，隨著濃度的上升，Tb、Ts、Tgel、Tonset, G'、Tonset, G'隨之下降；不同濃度之PNIPAM水溶液，其Tb>Ts>Tgel>Tonset, G' >Tonset, G'；亦使用光學顯微鏡量測cloud point，並觀察其相分離形態；所得到的Tb,cp約為31.60 oC且到達相分離溫度後，相分離會持續進行；以不同升溫速率所觀察到之相分離形態不同。

本研究亦證明了，國家同步輻射中心之小角度X光散射(SAXS)實驗可得PNIPAM水溶液之Ts，而得到之Ts約為32 oC左右。

關鍵字：聚(異丙基丙烯醯胺)、流變性質、相分離、光學顯微鏡、SAXS

The poly(isopropyl acrylamide) (PNIPAM) aqueous solution has a phase change behavior of lower critical solution temperature (LCST), that is, a uniform phase when the aqueous solution temperature is lower than the phase separation temperature, and higher than the phase separation temperature when the aqueous solution temperature is lower than the phase separation temperature The PNIPAM molecular chain exhibits hydrophobicity, forms phase separation, and its LCST is close to room temperature. There is a literature mentioning neutron scattering (SANS), which can identify the phase separation of PNIPAM aqueous solution. This literature indicates that the contrast conditions of PNIPAM aqueous solution are unfavorable, so it is very challenging to use small angle X-ray scattering (SAXS) for this experiment. This explanation has aroused the interest of our research.

In this study, PNIPAM solution was prepared at a temperature lower than the phase separation temperature using deionized water as a solvent. By rheological dynamic test, the relationship between different concentrations of solution at the phase separation temperature and the enthalpy is measured, and then Tb, Ts, Tgel, Tonset, G', Tonset, G' are obtained. the cloud point is also measured by optical microscopy, and the phase separation morphology is observed; the phase separation will continue; The phase separation morphology observed at the rate is different.This study also proves that the small-angle X-ray scattering (SAXS) experiment of the National Synchrotron Radiation Center can obtain the Ts of the PNIPAM aqueous solution, and the Ts is about 32 oC.

Key words: Poly(isopropyl acrylamide), rheological properties, phase separation, optical microscopy, SAXS

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