球腔中氢键流体的吸附-解吸附转变:表面调控研究

Adsorption-desorption of Hydrogen Bonding Fluid Confined in a Spherical Cavity: the Role of Surface Regulation

集中讨论了球形微腔表面对腔中氢键流体相态结构的调控机制.为了揭示微腔表面对腔中氢键流体相平衡的影响,首先根据吸附-解吸附原理并利用经典流体的密度泛函理论计算了微腔中氢键流体的平衡密度分布,进而通过吸附-解吸附等温线及巨势等温线绘制出体系的相图.在此基础上,重点考察了球腔尺寸、表面作用强度和作用力程对氢键流体毛细凝聚及层化转变的影响.结果表明,这些因素可以有效地调控体系毛细凝聚和层化转变的临界约化温度、临界密度和相区大小等特征,从而阐明了表面调控的主要机制.研究结果为设计相关吸附材料提供了理论参考.

The effect of surface regulation on the phase behavior of hydrogen bonding（ HB） fluid confined in a nano-spherical cavity was investigated by phase equilibrium thermodynamics. We tried to reveal the important role of cavity surface playing in the adsorption-desorption transition of confined HB fluid when the fluid-surface interaction is a square-well potential. In this study,density functional theory for classical fluids was used together with the modified fundamental measure theory. It was found that the cavity surface could give rise to significant effects on the critical temperatures,critical densities and phase regions of layering transition and capillary condensation. As a result,one can regulate the phase equilibria and aggregated state of the HB fluid by changing the strength and range of fluid-surface interaction and the radius of spherical cavity. It is expected that the present study is helpful to design related adsorption materials or to study the phase behavior of nanofluids.