Transport through self-assembled colloidal shells (colloidosomes)

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• 作者：Nily Dan ; ^{dan@coe.drexel.edu}
• 刊名：Current Opinion in Colloids and Interface Science
• 出版年：2012
• 出版时间：June, 2012
• 年：2012
• 卷：17
• 期：3
• 页码：141-146
• 全文大小：369 K

文摘

Colloidosomes, namely, microcapsules coated by a colloidal shell, have been widely studied as potential carriers of active compounds for various applications. The colloidal shell differs from the shells of other ¡®somes?(liposomes, polymersomes) since it is a composite material with an impenetrable phase¡ªthe particles, and a penetrable one¡ªthe voids or pores between them. Recent analysis shows that in the shells composed of monodisperse and charged particles, the maximal volume fraction of colloids in the self-assembled layer depends on the size ratio between the particle's hard-sphere radius and the effective radius, which includes the range of repulsive electrostatic interactions. Thus, somewhat counter-intuitively, the density of particles in the shell increases with increasing particle radius. However, mixing particle sizes can lead to highly packed shells where the impenetrable phase volume fraction approaches 100 % . The diffusional flux through the colloidal shell is highly sensitive to the packing density (or particle volume fraction); this parameter sets the average size of the pores, their distribution through the shell, and their tortuosity. However, while in thick multi-layer shells the flux increases with increasing particle size, in the case of monolayer-thick shells there is no apparent dependence of the flux on the colloid dimensions.