表面富含羧基的单分散交联聚合物微球的快速自组装制备胶体晶的研究

在20～70℃范围内,用垂直沉积的方法可使表面富含羧基的单分散交联聚合物微球在不同的基底上快速自组装成三维有序的胶体晶.不同粒径的微球形成的胶体晶其光禁带峰位不同,因此可调控不同波长的光在胶体晶中的传播.利用紫外-可见光谱研究了胶体晶的光禁带峰位与组成其微球粒径之间的关系.结果表明,随着构成胶体晶微球粒径的增大,胶体晶光禁带峰位发生了红移,而随着入射光角度的增大,胶体晶的光禁带峰位发生了蓝移.利用原子力显微镜和扫描电子显微镜研究了其它条件对聚合物微球有序排列的影响,发现聚合物微球在pH值为3.0～13.0范围内可以形成三维有序自组装胶体晶.这是由于在不同的pH值下,聚合物微球表面发生羧基化及去羧基化反应,导致在自组装过程中微球之间和微球与介质之间作用力的变化

Investigation on Colloidal Crystals Fabricated by Rapid Self-assembly of Monodispersed Cross-linked Carboxy-modified Polymer Microspheres

By means of vertical deposit method on several kinds of substrates, mondispersed cross-linked-carboxy modified polymer microspheres were self assembled into colloidal crystals rapidly in the temperature range of 20_70 ℃. The colloidal crystals fabricated by the polymer microspheres with different diameters show different stop-bands due to the Bragg diffraction. The relationship between the stop-band of colloidal crystals and the diameters of polymer microspheres were investigated by using UV-Vis spectra. Experiments had proved that the stop band red-shefted with increasing the diameters of the polymer microspheres, while blue-shifted with the increasing of the incidence angle. It was studied that the effects of pH value and other factors on the self-assembly of these polymer microspheres by SEM and AFM. We found that the polymer microspheres could form colloidal crystals in a broad range of pH value from3.0 to 13.0, which was mainly based on the fact that the microspheres can change their surface properties by turning carboxy groups to their corresponding ions at different pH values. The property of these microspheres could manipulate the interactions among themselves in the self-assembly procedure, leading to the above results.