In this paper, we discussed the drying behavior of monodispersed polystyrene latex at high temperature with particular attention to the morphological evolution during film formation process. At the beginning of the water evaporation, a skin film with some defects was formed at latex/air interface, water evaporated thereby in a constant rate. During this stage, a drying front advanced from the top film towards the bulk dispersion. Afterwards, most water was lost, and water evaporation rate was less than that of the initial stage. In this case, the whole system became immobile, and another drying front developed from the interior region outside the system. Two distinct boundaries between completely dried region and wet region corresponding to the opposite directions of the second drying front were found if the film peeled from the container bottom surface. Besides, some particular morphologies were found in the completely dried region, which was likely related to preferable coalescence among the particles induced by capillary force due to water evaporation.
A method for preparing 3D ordered macroporous silicate materials was developed by using the ordered stacking structure of monodispersed polystyrene latex as a template. By using a modified sol\|gel procedure, the ordered template was permeated and filled with silicate, and the title porous materials was formed after removing the template by calcination at high temperature. Moreover, the pores were highly ordered throughout all the sample. After observing the morphological profile of the sample before calcination, it was found that silicate existed in two typical morphologies: monodispersed particles in the cavities and interconnected network within the interstice of the template. The transition morphology was rod\|like formed by the condensation of the silicate monodispersed particles. Two aspects concerning with the template effects of the ordered latex film were emphasized: the polymeric spheres may result in orderly packed holes after calcination, and the dielectric interfacial layer surrounding the polymeric spheres may induce the formation of monodispersed silicate spheres with ordered stacking. Both aspects played important roles in the formation of the highly ordered inorganic porous materials by calcination the gel at high temperature.
