A novel approach to thermoporometry is proposed. Thermal transformations in a confined liquid were investigated using positron annihilation lifetime spectroscopy (PALS). The SBA-3 silicas with a regular pores with sizes of about 2 nm or 3 nm wetted with n-hexane were used in experiments as model solid/liquid systems. The information obtained from in situ monitoring by PALS allows to infer about the evolution of the amount of n-hexane remaining in the pores as well as empty pore space. Moreover, the changes in the coverage of silica by alkane and the degree of pore opening are simultaneously detected. The investigations provided a deeper insight into the mechanism of thermal evacuation of the condensate from the pores. The most important finding is that during thermodesorption, liquid n-hexane filling the pores splits into plugs separated by empty volumes rather than being removed layer-by-layer from the surface. The pore size distributions derived from the PALS results obtained at the saturated vapor pressure of n-hexane and the results of thermogravimetry at atmospheric pressure are consistent with each other. However, comparing them with the results of low-temperature nitrogen adsorption suggests that using the Kelvin equation is not suitable for n-hexane in such small pores.

提出了一种新颖的热孔法。使用正电子an没寿命光谱（PALS）研究了密闭液体中的热转化。在SBA-3的二氧化硅用具有约2nm或3nm的大小的规则孔润湿Ñ正己烷在实验中使用的模型如固体/液体系统。从原位由PALS监视获得的信息允许推断关于量的演变Ñ正己烷残留在孔隙以及空孔空间。此外，同时检测到烷烃对二氧化硅的覆盖率的变化和开孔程度。这些研究为从孔中热排空冷凝液提供了更深入的见解。最重要的发现是在热脱附过程中，液体Ñ己烷填充孔分裂成分离的插头通过空卷而不是从表面上除去层-层。从在饱和蒸气压获得的PALS结果导出的孔径分布Ñ正己烷和热的在大气压力的结果是相互一致。然而，随着低温氮吸附的结果对它们进行比较表明，使用Kelvin公式是不适合Ñ在这样小的孔-己烷。