Sacanna S, Kegel W K, Philipse A P
Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Langmuir. 2007 Oct 9;23(21):10486-92. doi: 10.1021/la701311b. Epub 2007 Sep 7.
Charge-stabilized dispersions of inorganic colloids are shown to induce spontaneous emulsification of hydrophobic (TPM) molecules to stable oil-in-water emulsions, with monodisperse, mesoscopic oil droplet diameters in the range of 30-150 nm, irrespective of the polydispersity of the starting dispersions. The results for cobalt ferrite particles and commercial silica sols extend our first study (Sacanna, S.; Kegel, W. K.; Philipse, A. Phys. Rev. Lett. 2007, 98, 158301) on spontaneous emulsification induced by charged magnetite colloids and show that this type of self-assembly is quite generic with respect to the composition of the nanoparticles adsorbing at the oil-water interface. Moreover, we provide additional experimental evidence for the thermodynamic stability of these mesoemulsions, including spontaneous oil dispersal imaged by confocal microscopy and monitored in situ by time-resolved dynamic light scattering. We discuss the possibility that thermodynamic stability of the emulsions is provided by the negative tension of the three-phase line between oil, water, and adsorbed colloids.
无机胶体的电荷稳定分散体可诱导疏水性（TPM）分子自发乳化形成稳定的水包油乳液，其介观油滴直径单分散，范围在30 - 150纳米，与起始分散体的多分散性无关。铁酸钴颗粒和商用硅溶胶的结果扩展了我们首次关于带电磁铁矿胶体诱导自发乳化的研究（Sacanna, S.; Kegel, W. K.; Philipse, A. Phys. Rev. Lett. 2007, 98, 158301），并表明这种自组装对于吸附在油水界面的纳米颗粒组成而言相当普遍。此外，我们为这些中乳液的热力学稳定性提供了额外的实验证据，包括通过共聚焦显微镜成像并通过时间分辨动态光散射原位监测的自发油分散。我们讨论了乳液的热力学稳定性由油、水和吸附胶体之间三相线的负张力提供的可能性。
