Paradox of stability of nanoparticles at very low ionic strength.
Paradox of stability of nanoparticles at very low ionic strength.
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DOI：
10.1021/la3016589
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发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
Shihong Lin;M. Wiesner
中科院分区：
文献类型：
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作者：
Shihong Lin;M. Wiesner
重新检查了从板-板系统到球-板系统的双电层相互作用能的缩放，并且发现不诉诸Derjaguin近似的精确缩放理论上预测了纳米颗粒在耗尽添加的电解质的水中的不稳定性，并且因此在中等离子强度下具有最大稳定性。该理论特征再次强调了所添加的电解质的双重作用性质，该双重作用性质由直接表面力测量的实验结果支持，但不由纳米颗粒沉积/聚集的胶体稳定性的实验结果支持。讨论了理论预测与实验观测之间以及不同体系中实验观测之间的不一致性。可能的原因导致的不一致性进行了探讨，包括曲率的影响，从抗衡离子的贡献，相互作用的模式，和平衡模型来描述的胶体相互作用的纳米粒子悬浮液的适用性。
The scaling of electrical double layer interaction energy from a plate-plate system to a sphere-plate system was reexamined, and it was found that accurate scaling without resorting to the Derjaguin approximation theoretically predicts the destabilization of nanoparticles in water depleted of added electrolyte and, consequentially, a maximum stability at a moderate ionic strength. This theoretical feature re-emphasizes the dual-role nature of added electrolyte that was supported by experimental results of direct surface force measurement but not by those of colloidal stability of nanoparticle deposition/aggregation. Inconsistences between the theoretical prediction and the experimental observation and between experimental observations in different systems were discussed. Possible reasons leading to the inconsistences were explored, including the effect of curvature, the contribution from counterions, the mode of interaction, and the applicability of an equilibrium model to describe the colloidal interaction of a nanoparticle suspension.