Polymeric Particles with Structural Complexity from Stable Immobilized Emulsions

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• 作者：Shin-Hyun Kim ; Chul-Joon Heo ; Su Yeon Lee ; Gi-Ra Yi ; Seung-Man Yang
• 刊名：Chemistry of Materials
• 出版年：2007
• 出版时间：September 18, 2007
• 年：2007
• 卷：19
• 期：19
• 页码：4751 - 4760
• 全文大小：1306K
• 年卷期：v.19,no.19(September 18, 2007)
• ISSN：1520-5002

文摘

We prepared polymeric structures with unusual complexity in surface morphology derived fromphotocurable emulsion droplets dispersed in an aqueous medium. The emulsion droplets a few tens ofmicrometers in size were stabilized with relatively small hydrophobic particles that were bound to theemulsion interfaces. The particle binding tended to immobilize the oil-in-water emulsion interface anddramatically increased the structural relaxation time of the interface deformation over a few days relativeto a few milliseconds for an otherwise clean interface. In particular, perfectly immobilized emulsiondrops maintained nonspherical elongated structures that were formed by shear-induced emulsificationand could not be relaxed to a spherical shape. This property is useful for broad research areas rangingfrom crystallography and buckling phenomena to materials fabrication. The configuration of small particleson the interface and the "raspberry" shape of particle-stabilized emulsions were captured successfully byphotocuring the emulsion droplets because the small bound particles immobilized the emulsion droplets.By selectively removing the small particles from the particle-covered polymeric structures, we prepareddimpled microparticles with various shapes. The dimple geometry depended on the interfacial propertiesor phase affinity of the small particles. The contact angle and binding energy of the particles were calculatedon the basis of the dimple geometry. In addition, buckling phenomena of the particle-stabilized emulsionswere observed when volatile oil was added to the photocurable resin.