The Examination Of Floating Self-Assembly Of Colloidal Spheres At Liquid-Air Interface Of Suspension

Colloidal crystals attracted many people's interest in the last decade,and it would be a active field of research.It was used to optoelectronic materials and engineering,biomedical,macroporous materials and so on.In recently,there are many methods which can get colloidal crystals in the world. For example: gravity deposition, centrifugal deposition, vertical deposition, physical force method and floating self-assembly.In this paper we main fabricate the basic unit which is polystyrene (PS) of colloidal crystals with emulsion polymerization. We can revise concentration of emulsifier, initiator, buffer, styrene and temperature to control the size and the relative standard deviation of PS. In the experiments,PS spheres with the diameter range from 100nm to 1000nm were fabricated with a narrow size distributed(1ess than 5%),respectively. On this basis, we use PS spheres which were fabricated in the laboratory to self-assembly at liquid-air interface of suspension. The dispersion medium was fabricated by ethanol and water. We could change the ratio of ethanol and water in the dispersion medium, the initial concentration of PS spheres and temperature to investigate the quality of colloidal crystals. We discuss to the influence of ethanol to the process of self-assembly.Then we use SiO₂ and PS spheres with self-assembly at water-air interface of suspension, we can get binary colloidal crystals. We change the diameter ratio of colloidal spheres, the ratio of concentration and temperature to investigate the pattern of binary colloidal crystals. At last we discuss the initial mechanism of self-assembly at water-air interface to fabricating binary colloidal crystals.