垂直沉积法组装二元聚苯乙烯胶粒晶体

Fabrication of polystyrene binary colloidal crystals by vertical deposition

采用垂直沉积法组装了二元聚苯乙烯胶粒晶体,研究了两种聚苯乙烯胶体微球的粒径比、质量比、温度和分散介质中乙二醇含量等因素对二元聚苯乙烯胶粒晶体组装花样的影响.粒径比>4.45、质量比≥74∶26是形成面心立方二元聚苯乙烯胶粒晶体的必要条件.组装温度为60℃,分散介质中乙二醇质量分数为6%时,可得到更高质量的二元聚苯乙烯胶体晶体.胶体微球二元垂直沉积机理研究表明:两种聚苯乙烯胶体微球是同时在基片的表面进行组装的;胶体微球在介质中的布朗运动、沉降速率及其在基片表面的组装速率三者之间匹配越好,所得二元聚苯乙烯胶粒晶体质量越高.

Binary colloidal crystals were fabricated by a vertical deposition method with two sub-micrometer size polystyrene （ PS） microspheres. The self-assembled patterns of binary colloidal crystals （ bCCs） were investigated by varying the size ratio, the mass ratio of PS microspheres, the temperature and content of ethylene glycol in water. It is found that PS binary colloidal crystals with face-centered cube （fcc） arrangement can be obtained while the size ratio is more than 4. 45 and the mass ratio is not less that 74：26. High-quality PS binary colloidal crystals are easily generated at the temperature of 60℃ and the mass fraction of ethylene glycol in dispersing medium of 6%. The study also shows that self-assembly of two PS microspheres on the substrate surface is operated at the same time, and in this regard the vertical deposition method has a great deal of difference from other methods. In addition, PS binary colloidal crystals have a higher quality with the increase of matching between Brownian motion, sedimentation rate of PS colloidal microspheres in water, and self-assembly rate on the substrate surface.