Development of Integrated Method for Nanopore Characterization Based on Peculiar Phase Behavior of Fluids Confined in Nanospace

许多工业上重要的多孔材料具有纳米级的孔。纳米孔的孔径表征通常通过氮吸附进行，使用所谓的开尔文冷凝模型进行分析，尽管吸附科学家已经普遍认为开尔文模型在纳米范围内的孔中存在不足，这是缺乏合适的工程模型来估计纳米级孔径的直接证据。本研究是建立一个简单而准确的模型表征纳米孔，基于对纳米空间中的流体的特殊相行为的理解，其中孔壁的相互作用势能会阻碍受限流体的相边界。主要结论如下：1.吸附等温线测量：我们以前提出的模型的有效性，占孔壁势能的贡献，临界冷凝 ...更多信息 通过使用FSM-16的检查证明了纳米孔中的压力。此外，还测量了不同固体材料（多孔和非多孔）和吸附物组合的等温线，这将代表用于确定相互作用能强度的数据库.相互作用强度：另一个先前提出的模型，这是发现氮和孔壁之间的相互作用强度，被发现需要改进的吸附物与较弱的相互作用。因此开发了一个新的模型，利用亨利区的等温线与较低的压力范围，与冷凝模型可以估计一致的孔径，而不管所采用的吸附质-开尔文模型当然不能成功.利用原子力显微镜（AFM）研究凝固转变：采用胶体探针AFM技术，测量了碳颗粒与石墨基体在环己烷中形成的准狭缝纳米空间之间的作用力曲线，并确定了不同尺寸纳米空间的凝固点。发现结果与如上确定的相互作用强度一致。基于上述结果以及分子模拟结果，我们认为包含孔壁相互作用强度这一重要因素的相变模型能够较准确地描述纳米孔中流体的相行为，其现在代表基于纳米空间中的特殊相行为的用于纳米孔表征的集成方法。少

Many of industrially important porous materials possess nanometer order of pores. Pore size characterization for nanopore is usually done through nitrogen adsorption, using so-called the Kelvin condensation model for the analysis, although it is already common understanding for adsorption scientists that the Kelvin model has a deficit of the underestimation in the nanometer range of pores, which is a direct evidence for the lack of a suitable engineering model for estimating nanoscale pore size. The present study is to develop a simple and accurate model for nanopore characterization, based on the understanding of peculiar phase behavior of fluids confined in nanospace, where the interaction potential energy of pore wall would hinder the phase boundaries of the confined fluids. The conclusions are as follows.1. Adsorption isotherm measurement: The validity of our previously proposed model that accounts for the contribution of the pore-wall potential energy to the critical condensation … More pressure in nanopores was demonstrated through examination employing FSM-16. Further, isotherms with various combination of solid materials (both porous and nonporous) and adsorbates were measured, which would stand for the database for determining strength of interaction energies.2. Interaction strength: Another previously proposed model, which is for finding the interaction strength between nitrogen and a pore wall, was found to need improvement for adsorbates with weaker interaction. A new model utilizing Henry region of isotherm with lower pressure range was thus developed, with which the condensation model can estimate consistent pore sizes regardless of the adsorbate employed -- The Kelvin model can not of course be as successful.3. Study of freezing transition by atomic force microscopy (AFM): Employing so-called the colloidal probe AFM technique, the force curves between a carbon particle and a graphite substrate immersed in cyclohexane, which form quasi-slit nanospace, were measured and the freezing points in various sizes of nanospace were determined. The results were found to be consistent with the interaction strength determined as above. Thus a unique physical property of the interaction strength was able to describe both condensation and freezing phenomena comprehensively.Based on the above results, as well as those employing molecular simulations, it is concluded that the phase transition models including the important factor of the pore-wall interaction strength were confirmed to be able to describe the phase behavior of fluids in nanopores with sufficient accuracy, which now stand for the integrated method for nanopore characterization based on the peculiar phase behavior in nanospace. Less