Towards the description of adsorption of water in slit-like pores with walls covered by molecular brushes.
Towards the description of adsorption of water in slit-like pores with walls covered by molecular brushes.
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描述了壁被分子刷覆盖的狭缝状孔隙中水的吸附。
DOI：
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发表时间：
2018
影响因子：
4.4
通讯作者：
S. Sokołowski
中科院分区：
文献类型：
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作者：
V. M. Trejos;O. Pizio;S. Sokołowski
在密度泛函理论的框架下，研究了水模型在缝状孔中的密度分布、吸附等温线和相行为.每个链通过其末端链段结合到表面，并且接枝链的表面密度对于每个壁是相同的。水的模型取自Clark等人的工作[Mol. Phys.104，3561（2006）]成功地再现了体状态方程。平均场方法已被用来描述吸引相互作用的影响。采用Wertheim的一级热力学微扰理论，考虑了化学缔合效应。我们已经发现，在孔壁上的分子刷的存在下，具有重要的后果的吸附和相行为的承压水。如果刷段不吸引水分子强烈，汽液共存包络收缩时增加刷密度，但临界温度的影响很弱。从毛细冷凝蒸发的变化观察到的刷密度的变化，拴系链的段数，和/或段的化学身份。交叉温度受所有这些因素的影响。此外，我们已经表明，亲和力的水链段是一个重要的因素，确定吸附的水蒸气和整个相图。
The density profiles, adsorption isotherms, and phase behavior of a water model in a slit-like pore with walls modified by pre-adsorbed tethered chain molecules have been studied in the framework of a density functional theory. Each chain is bonded to the surface by its terminal segment, and the surface density of grafted chains is the same for each wall. The model for water taken from the work of Clark et al. [Mol. Phys. 104, 3561 (2006)] reproduces successfully a bulk equation of state. The mean field approach has been used to describe the effects of attractive interactions. The chemical association effects are taken into account by using the first-order thermodynamic perturbation theory of Wertheim. We have found that the presence of molecular brushes on the pore walls has important consequences for the adsorption and phase behavior of confined water. If the brush segments do not attract water molecules strongly, the vapor-liquid coexistence envelope shrinks upon increasing brush density, but the critical temperature is weakly affected. Alteration from capillary condensation to evaporation is observed with changes in the brush density, number of segments of tethered chains, and/or chemical identity of segments. The crossover temperature is affected by all these factors. Moreover, we have shown that affinity of water to segments of tethers is an important factor determining adsorption of water vapor and the entire phase diagram.