Studies On Preparation Of PS Colloid Spheres And The Application Of Colloid Crystal Templates

The mono-disperse Polystyrene (PS) colloid spheres with controllable size were synthesized by the seeded emulsion polymerization and Emulsifier-free emulsion polymerization. Polystyrene (PS) colloid spheres crystal array was assembled by dip-drawing method and ordered SiO2, TiO2 nano-structure were fabricated by using the PS colloid crystal as template. The forming mechanism of colloid spheres and colloid crystal were discussed, the advantage of dip-drawing method to assemble PS template was exhibited, the influence of fabricating parameters on the preparation of spheres, array quality and morphology of nano-structure was studied; and the structure of PS array,SiO2 and TiO2 were analyzed.The seeded emulsion polymerization was prepared by using styrene as monomers, KPS as initiator, SDS as emulsifier. The influence factors on PS colloid sphere diameter have been investigated. The results revealed:When other factors were kept constant, the diameter of PS colloid spheres increased with monomer concentration. When the initiator reagent increased, the diameter of PS colloid spheres increased; When the concentration of emulsifier increased, the diameter of PS colloid spheres decreased.The Emulsifier-free emulsion polymerization was prepared by using styrene as monomers, KPS as initiator. The influence factors of monomer, initiator and polymerize time on PS colloid sphere diameter have been investigated:When other factors were kept constant, the diameter of PS colloid spheres increased with monomer concentration. When the initiator reagent increased, the diameter of PS colloid spheres decreased; When the polymerize time increased, the diameter of PS colloid spheres increased.In the course of PS sphere assembly in meniscus at the solid/liquid interface, the absorption force, flotage and capillary force are responsible to the nucleation and growth of colloid crystal. Dip-drawing method enlarges the evaporation area of the wet array due to the quicker movement of leading edge, so that the solvent evaporation and solution flux are accelerated.Appropriate drawing rate can obtain highly ordered colloid crystal templet. The properties of base plate have effect on morphology of colloid crystal templet, the base plates should be clean and enev. To obtain a perfect colloid crystal, the sphere diameter should be homogeneous.With dipping method used to fill sol into the PS array can lead to a stable filling content by capillary force. The concentration of sol and sol particle diameter are important factors on effecting nano-structure. The choice of the sol concentration used should match to the sphere size to obtain ordered nano-structure, because the appearance of nano-structure is affected by both PS sphere diameter and sol concentration.The nano-structure was obtained after dryness and removing PS template, then it is characterized by SEM.