Above their cloud point, aqueous solutions of the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAM) form large mesoglobules. We have carried out very small-angle neutron scattering (VSANS with q = 0.21–2.3 × 10^–3 Å^–1) and Raman spectroscopy experiments on a 3 wt % PNIPAM solution in D₂O at atmospheric and elevated pressures (up to 113 MPa). Raman spectroscopy reveals that, at high pressure, the polymer is less dehydrated upon crossing the cloud point. VSANS shows that the mesoglobules are significantly larger and contain more D₂O than at atmospheric pressure. We conclude that the size of the mesoglobules and thus their growth process are closely related to the hydration state of PNIPAM.

中文翻译：

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水溶液中聚 (N-异丙基丙烯酰胺) 中小球形成的压力依赖性

高于其浊点，热响应聚合物聚（N-异丙基丙烯酰胺）（PNIPAM）的水溶液形成大的中小球。我们在大气压和^高压_（^高达113 _兆帕）。拉曼光谱显示，在高压下，聚合物在越过浊点时脱水程度较低。VSANS 显示中小球明显更大且包含更多 D ₂O 比在大气压下。我们得出结论，中小球的大小以及它们的生长过程与 PNIPAM 的水合状态密切相关。