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arXiv 1010.1807cond-mat.softcond-mat.stat-mech
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添加强亲水性或疏水性溶质的含水混合物中的沉淀

Precipitation in aqueous mixtures with addition of strongly hydrophilic or hydrophobic solute

Ryuichi Okamoto, Akira Onuki

摘要:

我们研究相分离的水溶液中的混合物,由于优先溶剂化与低密度溶质(亲水性离子或疏水性颗粒)。对于亲水性离子,优先溶剂化可以稳定富含离子的水域。这种沉淀发生在温度和平均组成的宽范围内,高于临界溶质密度$n_p$,其中混合物溶剂将处于没有溶质的单相状态。当平均溶质密度$\bar n$降低到$n_p$或当相互作用参数$χ$降低到临界值$χ_p$时,析出畴的体积分数趋于零。如果我们从具有${\bar n}>n_p$或$χ>χ_p$的单相状态开始,沉淀通过均匀成核或通过非均匀成核进行,例如,在悬浮的胶体周围。在后一种情况下,胶体颗粒被厚的润湿层包裹。我们还预测了一个一阶预湿转变为$\bar n$或$χ$略低于$n_p$或$χ_p$。

英文摘要:

We examine phase separation in aqueous mixtures due to preferential solvation with a low-density solute (hydrophilic ions or hydrophobic particles). For hydrophilic ions, preferential solvation can stabilize water domains enriched with ions. This precipitation occurs in wide ranges of the temperature and the average composition above a critical solute density $n_p$, where the mixture solvent would be in a one-phase state without solute. The volume fraction of precipitated domains tends to zero as the average solute density $\bar n$ is decreased to $n_p$ or as the interaction parameter $χ$ is decreased to a critical value $χ_p$. If we start with one-phase states with ${\bar n}>n_p$ or $χ>χ_p$, precipitation proceeds via homogeneous nucleation or via heterogeneous nucleation, for example, around suspended colloids. In the latter case, colliod particles are wrapped by thick wetting layers. We also predict a first-order prewetting transition for $\bar n$ or $χ$ slightly below $n_p$ or $χ_p$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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