Abstract In this communication, the general possibility of performing short-term measurements on the unstable states of partially-soluble binary liquids has been demonstrated on an example of a binary PPG-425/water solution having a lower critical solution temperature (LCST). For this purpose, the fast transition of the initially stable solution to the region of unstable states above the liquid-liquid spinodal was carried out using the method of controlled pulse heating with microsecond time resolution. For the purposes of the experiment, the pressure was varied from subcritical to supercritical values. At a given pulse length (from 10-4 to 10-3 s), we revealed the phenomenon of significant (of the order of 100 K) superheating of the solution with respect to the spinodal. In the course of deeper penetration into the region of unstable states, we observed a change in the mode of heat transfer in the solution, which is confined in time and reproducible with respect to temperature. We attribute this phenomenon, which resembles the stepwise onset of the convective heat transfer mode, to the onset of spinodal decomposition as the most natural relaxation process occurring in this part of the phase diagram.

中文翻译：

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用 LCST 对混合物的热致不稳定状态进行短期测量

摘要 在本文中，以具有较低临界溶解温度 (LCST) 的二元 PPG-425/水溶液为例，证明了对部分可溶二元液体的不稳定状态进行短期测量的一般可能性。为此，使用具有微秒时间分辨率的受控脉冲加热方法，将初始稳定解快速过渡到液-液旋节线上方的不稳定状态区域。为了实验的目的，压力从亚临界值变化到超临界值。在给定的脉冲长度（从 10-4 到 10-3 s），我们揭示了溶液相对于旋节线的显着（大约 100 K）过热现象。在深入渗透到不稳定状态区域的过程中，我们观察到溶液中的传热模式发生了变化，这种变化受到时间限制，并且在温度方面可重现。我们将这种类似于对流传热模式的逐步开始的现象归因于旋节线分解的开始，这是相图这一部分中发生的最自然的弛豫过程。