Petrov Oleg, Furó István
Division of Physical Chemistry, Department of Chemistry, Royal Institute of Technology, SE-10044 Stockholm, Sweden.
Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Jan;73(1 Pt 1):011608. doi: 10.1103/PhysRevE.73.011608. Epub 2006 Jan 31.
We recapitulate and generalize the concept of the freezing-melting hysteresis that attributes this phenomenon to a free-energy barrier between metastable and stable states of pore-filling material. In a phenomenological description, we show that under commonly encountered conditions, this renders the freezing-point depression DeltaTf defined by the surface-to-volume ratio S/V, whereas the melting-point depression DeltaTm, by the mean curvature kappa of the pore surface, with DeltaTm/DeltaTf =2kappa(V/S). Employing 1H NMR cryoporometry, we experimentally demonstrate the linear correlation between DeltaTm and DeltaTf for several liquids with different DeltaTf,m imbibed in controlled pore glasses. The results compare favorably to the morphological properties of the glasses determined by other techniques. Our findings suggest a simple method for analyzing the pore morphology from the observed phase transition temperatures.
我们概括并推广了冻融滞后的概念，该概念将此现象归因于孔隙填充材料亚稳态和稳态之间的自由能势垒。在现象学描述中，我们表明，在常见条件下，这使得由表面积与体积比S/V定义冰点降低量ΔTf，而熔点降低量ΔTm由孔隙表面的平均曲率κ定义，其中ΔTm/ΔTf = 2κ(V/S)。利用1H NMR低温孔率测定法，我们通过实验证明了几种具有不同ΔTf,m的液体渗入可控孔隙玻璃时，ΔTm与ΔTf之间的线性相关性。结果与通过其他技术测定的玻璃形态学特性吻合良好。我们的研究结果提出了一种从观察到的相变温度分析孔隙形态的简单方法。
