Auernhammer Günter K, Vollmer Doris, Vollmer Jürgen
Max Planck Institute for Polymer Research, Ackermannweg 10, 53118 Mainz, Germany.
J Chem Phys. 2005 Oct 1;123(13):134511. doi: 10.1063/1.2046608.
Binary liquid mixtures can show pronounced oscillations in the differential scanning calorimeter signal for the specific heat and in the turbidity when phase separation is induced by continuously ramping the temperature. For a fixed ramp rate, i.e., a linear temporal drift of temperature, only a small number of oscillations have been observed. In the present manuscript we describe an experimental setup where simultaneous video-microscopy and shadow-graph measurements can be performed on mixtures subjected to an arbitrary temporal temperature evolution. In particular, it can be adjusted to fix the thermodynamic driving force, which characterizes the rate of change of the composition of the coexisting phases. With this novel technique both the number of oscillations and the temperature interval where oscillations are observed increase significantly. This technique can easily be applied to a great variety of binary mixtures, permitting detailed investigations of their phase-separation kinetics under slowly ramping temperature.
当通过连续升温诱导相分离时，二元液体混合物在差示扫描量热仪的比热信号和浊度方面会表现出明显的振荡。对于固定的升温速率，即温度的线性时间漂移，仅观察到少量振荡。在本论文中，我们描述了一种实验装置，在该装置中，可以对经历任意时间温度变化的混合物同时进行视频显微镜和阴影图测量。特别地，它可以被调整以固定热力学驱动力，该驱动力表征了共存相组成的变化速率。使用这种新技术，振荡的数量以及观察到振荡的温度区间都显著增加。该技术可以很容易地应用于各种各样的二元混合物，从而允许在缓慢升温的条件下对其相分离动力学进行详细研究。
