Ordering and potential appearance of a phase transition in low-tenperature liquid confined within meso-pores

用绝热量热法研究了液态环己烷和苯的低温热性质。发现有三个特点被指出。首先，玻璃化转变温度以及导致转变的基本过程没有随孔径发生大的变化。二是热容曲线呈现平缓的峰值，峰值温度随直径的增大而降低，表明在本体液体中的峰值将出现在玻璃化转变温度以下。这被理解为是由聚集体的允许分子构型的数量的空间限制引起的。第三，在环己烷的情况下，在直径约2.1 nm的孔中出现相转变。这意味着，一个特殊的结构固有的液体基本一个将稳定在孔内，包括分子和孔壁之间的原子间的相互作用。

Low-temperature thermal properties of liquid cyclohexane and benzene were studied by adiabatic calorimetry. Three features were found to be pointed out. The first is that the glass transition temperature and therefore the elementary process causing the transition reveal no big change with the pore diameter. The second is, the heat capacity curve displays a gentle peak and the peak temperature decreases with increasing the diameter, indicating that the peak in bulk liquid would appear below the glass transition temperature. This is understood as caused by the spatial restriction in the number of the permitted molecular configurations of the aggregates. The third is, in the case of cyclohexane, a phase transition appears in the pores with diameter around 2.1 nm. This implies that a special structure inherent to the liquid elementary one would be stabilized within the pores with including the inter-atomic interactions between the molecules and pore wall.