利用胶体系统研究玻璃态

Glass studies in colloidal systems

玻璃态是一种无序结构的固体,组成单元可以是原子、分子、高分子、胶体粒子等等。尽管玻璃态材料在生活中很常见,有广泛的工业应用,但相关理论,尤其是液体到玻璃态转变的理论是物理学中争议最多的领域之一。溶液中的胶体粒子可以形成晶体、液体、玻璃等各种态。在光学显微镜下可以直接看到三维内部单个微米胶体粒子,通过图像处理还可以得到粒子的布朗运动轨迹,从而得到玻璃化转变过程中的微观动力学信息,这是原子分子玻璃系统中难以测量的。文章介绍了胶体作为模型系统对玻璃态的研究,主要包括传统的过冷液体到玻璃态的转变,另外还涉及气相、凝胶、多晶等其他无序或半无序态与玻璃态之间的过渡或转变。

Glasses are disordered solids composed of atoms, molecules, polymers or colloids etc. Glasses are ubiquitous in daily life and have broad applications in industry. However,the theoretical understanding of glassy materials, especially the glass transition, remains a highly controversial area in physics. Colloidal particles in liquid suspensions can form various phases such as crystals, liquids, and glasses. Micrometer-sized colloidal particles can be directly observed even inside the three-dimensional bulk phase using optical microscopy and their Brownian motions can be tracked by image analysis. Such dynamics of individual particles in bulk can hardly be measured in atomic or molecular systems. Here we review the studies of glasses using colloidal model systems. We mainly focus on the transition from supercool liquid to glass, and briefly discuss the crossover between glass and other disordered or partially disordered states such as polycrystals, gels, and vapors.