Tanaka Hajime, Meunier Jacques, Bonn Daniel
Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Mar;69(3 Pt 1):031404. doi: 10.1103/PhysRevE.69.031404. Epub 2004 Mar 19.
Two types of isotropic disordered nonergodic states exist in colloidal suspensions: glasses and gels. The difference between the two is that the nonergodicity, or elasticity, of gel stems from the existence of a percolated network, while that of glass stems from caging effects. Despite this clear difference in the origin of nonergodicity, it is not straightforward to distinguish the two states in a clear manner. Taking a Laponite suspension as an explicit example, we propose a general phase diagram for charged colloidal systems. It follows that a transition from the glass to the gel state can be induced by changing the interparticle interactions from predominantly repulsive to attractive. This originates from the competition between electrostatic Coulomb repulsion and van der Waals attraction. If the repulsion dominates, the system forms a Wigner glass, while in a predominantly attractive situation it forms a gel. In the intermediate region, where both repulsive and attractive interactions play roles, it may form an attractive glass.
玻璃态和凝胶态。两者的区别在于，凝胶的非遍历性或弹性源于渗流网络的存在，而玻璃的非遍历性则源于笼效应。尽管非遍历性的起源存在明显差异，但要清晰地区分这两种状态并非易事。以锂皂石悬浮液为例，我们提出了带电胶体系统的通用相图。结果表明，通过将粒子间相互作用从主要的排斥变为吸引，可以诱导从玻璃态到凝胶态的转变。这源于静电库仑排斥和范德华吸引之间的竞争。如果排斥占主导，系统形成维格纳玻璃，而在主要为吸引的情况下则形成凝胶。在排斥和吸引相互作用都起作用的中间区域，可能形成吸引玻璃。
