OBSERVATION OF FILM FORMATION OF LATEX DISPERSIONS AT DIFFERENT RELATIVE HUMIDITY AND TEMPERATURE BY SYNCHROTRON SMALL-ANGLE X-RAY SCATTERING STUDY
Latices are dispersions of polymeric particles in a suspending medium, usually water. They are widely used as paper coatings, adhesive, paints etc. When water evaporates from a dispersion of latex particles, a transparent film is formed under appropriate condition.13 It is genarally accepted that there are three steps during the film formation process: increasing the particle concentration and ordering, particle deformation, and polymer chain diffusion across particle boundaries.4-7 However, the microscopic details of film formation are still a topic of considerable debate. In the present work, the structural evolution during film formation of latex dispersions at different temperature and relative humidity was investigated by means of synchrotron small-angle X-ray scattering (SAXS) technique. The evolution of the interplanar distance of (111) suggests that the relative humidity can influence the evaporation rate of water. However, the rate of interplanar distance change cannot be affected by the relative humidity, which indicated that capillary pressure is the dominant driving force in the second stage of film formation. In addition, we analyzed the structures of colloidal assemblies formed at evaporation temperatures of 10, 25, 35, and 50 ℃. At room temperature, high-quality colloidal crystals can be obtained. At higher temperature, on the other hand, the colloidal spheres randomly stack on the substrate before forming crystalline nuclei because increasing the evaporation temperature not only increases the kinetic energy of the colloidal particles but also increases the rate of water evaporation, thereby reducing the time scale on which particles shift to favorable lattice sites.
Xuelian Chen Jens Rieger Stephan V.Roth Rainer Gehrke Yongfeng Men
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chi BASF SE, Polymer Physics, 67056 Ludwigshafen, Germany HASYLAB am DESY, Notkestr.85,22607 Hamburg, Germany State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chi
国际会议
PP’2010，Jinan International Symposium on Polymer Physics(2010济南国际高分子物理学术研讨会)
济南
英文
242-243
2010-06-06（万方平台首次上网日期，不代表论文的发表时间）