Sedimentation Pattern of Polymer Colloidal Dispersions in the External Fields

本课题对聚合物胶体分散体干燥过程中的对流、沉降和干燥耗散模式等进行了深入的研究，主要结果如下：（1）在盖玻片、表面皿和玻璃皿上均形成了较宽的环状沉降模式，说明了水和胶体球的对流流动的重要作用。沉积球通过外部和/或向上对流与内部和/或向下沉积之间的平衡而改变其漂浮在基底上的半平衡位置。(2)形成宏观（宽环和辐条状线）和微观（细多辐条线、刺状、星形图案等）干燥图案。(3)本文详细研究了中国黑墨水和聚甲基丙烯酸甲酯、PMMA微球水悬浮液在高温和室温下的对流花样。宽环，辐条线（“寺田细胞”）和循环细胞结构，首次观察到，在基板上。(4)流场中的模式和理论讨论，包括对流，沉降和干燥耗散模式的计算模拟仍有待进一步研究。

In this project, the convectional, sedimentation and drying dissipative patterns during the course of drying polymer colloidal dispersions and others were studied intensively Main results obtained are summarized as following:(1) The broad ring-like sedimentation patterns were formed on a cover glass, a watch glass and a glass dish, which demonstrates the important role of the convectional flow of water and colloidal spheres. The sedimentary spheres changed their semi-equilibrium position floating over the substrates by the balancing between the outside and/or upward convectional flow and inner ward and/or downward sedimentation.(2) Macroscopic (broad rings and spoke-like lines) and microscopic (fine multiple spoke lines, sting-like, star-like patterns, etc) drying patterns formed.(3) Convectional patterns of Chinese black ink and aqueous suspensions of poly (methyl methacrylate), PMMA spheres have been studied in detail at the elevated and the room temperatures, respectively. Broad ring, spoke line ("Terada cells") and the circulating cell structures were observed, for the first time, on the substrates.(4) Patterns in a flow field and theoretical discussion including computational simulation on the convectional, sedimentation and drying dissipative patterns are still open for further study.