Novel Mini-Reactor of Silicone Oil Droplets for Synthesis of Morphology-Controlled Polymer Particles

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• 作者：Daisuke Nagao ; Tatsuya Ohta ; Haruyuki Ishii ; Arnout Imhof ; Mikio Konno
• 刊名：Langmuir
• 出版年：2012
• 出版时间：December 21, 2012
• 年：2012
• 卷：28
• 期：51
• 页码：17642-17646
• 全文大小：264K
• 年卷期：v.28,no.51(December 21, 2012)
• ISSN：1520-5827

文摘

Inside spaces of emulsion droplets can be used as mini-reactors for material synthesis. The novel application of sol鈥揼el derived silicone oil droplets as mini-reactors was examined for the case of polymerization of styrene (St) and comonomers with the oil-soluble initiator 2,2鈥?azobis(2,4-dimethylvaleronitrile). Polydimethylsiloxane (PDMS) droplets prepared from dimethylsiloxane were used as the mini-reactors, in which the polymerization of St without comonomers was first conducted. In the polymerization, the St/PDMS volume ratio was varied from 0.025 to 0.10. After the polymerization, each PDMS droplet contained a polystyrene (PSt) particle. The St/PDMS ratio of 0.05 enabled the synthesis of micrometer-sized, spherical PSt particles with low polydispsersity. Copolymerization of St with comonomers having hydrophilic groups deformed the spherical shape of particles to lens-like or disk-like morphologies that were obtained with acrylic acid or sodium 4-styrene sulfonate, respectively. In another copolymerization, with divinylbenzene used as a cross-linker, hemispherical polymer particles were formed. To diversify the particle morphologies further, the proposed mini-reactor synthesis was combined with the recently proposed silicone oil droplet templating method (Ohta et al., 2012). Around the PDMS droplets containing a polymer particle, polymeric shells with a depression were successfully formed with the proposed method. The remaining PDMS oil inside the polymeric shells was extracted with ethanol, which caused hemispherical polymeric bowl-shaped capsules having a protrusion on the inside.