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arXiv 1306.1703cond-mat.softcond-mat.mes-hallcond-mat.mtrl-scicond-mat.stat-mech
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各向异性胶体分散体自组装相的自发演化

Spontaneous evolution of self-assembled phases from anisotropic colloidal dispersions

Ravi Kumar Pujala, Nidhi Joshi, H. B. Bohidar

摘要:

我们调查的自发演化的各种自组装相态从一个均匀的水性分散体的高纵横比的蒙脱石(钠Clopartite)纳米粘土血小板接地的观察超过3.5年的时间。我们已经建立了该系统的tw-c相图,第一次在正常pH值条件下使用流变学实验无盐悬浮液,并已检测到这些悬浮液进行非平凡的相演变和老化动力学。在tw-c相空间中发现了独特的相分离、平衡流体和平衡凝胶。从流变学测量得到的Cole-Cole图表明存在相互连接的网络状结构,其中c > cg,cg是凝胶化浓度。所有的分散体形成稳定的溶胶在初始时间,并与老化的网络状结构被发现通过两种途径形成:一个为c < cg,通过相分离和另一个为c > cg,通过平衡凝胶化。这就要求重新审视老化MMT分散体系的相图。

英文摘要:

We investigate the spontaneous evolution of various self-assembled phase states from a homogeneous aqueous dispersion of high-aspect ratio Montmorillonite (Na Cloisite) nanoclay platelets grounded on the observations made over a period of 3.5 years. We have established the tw-c phase diagram for this system for the first time in salt-free suspensions under normal pH conditions using rheology experiments and have detected that these suspensions do undergo nontrivial phase evolution and aging dynamics. Distinctive phase separation, equilibrium fluid and equilibrium gels in the tw-c phase space are discovered. Cole-Cole plots derived from rheology measurements suggested the presence of inter connected network-like structures for c > cg, cg being the gelation concentration. All dispersions formed stable sols during the initial time, and with aging network-like structures were found to form via two routes: one for c < cg, by phase separation and another for c > cg, through equilibrium gelation. This has invoked and called for a revisit of the phase diagram of aging MMT dispersions.

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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