Bishop Kyle J M, Kowalczyk Bartlomiej, Grzybowski Bartosz A
Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208, USA.
J Phys Chem B. 2009 Feb 5;113(5):1413-7. doi: 10.1021/jp8056493.
Mixtures of oppositely charged nanoparticles (NPs) exhibit anomalous solubility behavior and precipitate either upon dilution or upon temperature increase. Precipitation is reversible and can be explained by a thermodynamic model that accounts for changes in the electrostatic interactions due to the adsorption/desorption of counterions from the surface of the NPs. Specifically, decreasing the salt concentration via dilution or increasing the temperature causes dissociation of counterions from the NP surfaces, increasing the magnitude of electrostatic interactions between NPs and resulting in their precipitation. Model predictions of NP solubility are in quantitative agreement with the experimental observations. Such predictions are of practical importance for the preparation of "patchy" electrostatic coatings and ionic-like NP supracrystals.
带相反电荷的纳米颗粒（NP）混合物表现出异常的溶解行为，在稀释或温度升高时会沉淀。沉淀是可逆的，可以用一个热力学模型来解释，该模型考虑了由于反离子从NP表面吸附/解吸而导致的静电相互作用的变化。具体而言，通过稀释降低盐浓度或升高温度会导致反离子从NP表面解离，增加NP之间静电相互作用的强度，从而导致它们沉淀。NP溶解度的模型预测与实验观察结果在定量上一致。这样的预测对于制备“斑驳”的静电涂层和类离子NP超晶体具有实际重要性。
