论文标题
胶体玻璃的表面熔化
Surface melting of a colloidal glass
论文作者
论文摘要
尽管他们的技术相关性，但仍然缺乏对眼镜的全面理解。这更适用于它们的表面，其特性与散装材料的特性很大不同。在这里，我们通过实验研究二维玻璃的表面与有效温度的关系。为了产生自由表面，我们使用通过可调临界卡西米尔力相互作用的微米大小颗粒的有吸引力的胶体悬浮液。与晶体类似，我们观察到玻璃的表面熔化，即，在玻璃温度以下的表面形成液膜。然而，在下面，我们发现一个意外的区域，具有散装密度但粒子动力学的速度更快。它是由高度移动颗粒的连接簇造成的，这些粒子在表面附近形成并深深地渗透到基础材料中。由于其厚度可以达到几十个颗粒直径，因此该层可能阐明薄玻璃膜的知识不足，这些特性在许多技术应用中发现
Despite their technological relevance, a full microscopic understanding of glasses is still lacking. This applies even more to their surfaces whose properties largely differ from that of the bulk material. Here, we experimentally investigate the surface of a two-dimensional glass as a function of the effective temperature. To yield a free surface, we use an attractive colloidal suspension of micron-sized particles interacting via tunable critical Casimir forces. Similar to crystals, we observe surface melting of the glass, i.e., the formation of a liquid film at the surface well below the glass temperature. Underneath, however, we find an unexpected region with bulk density but much faster particle dynamics. It results from connected clusters of highly mobile particles which are formed near the surface and deeply percolate into the underlying material. Because its thickness can reach several tens of particle diameters, this layer may elucidate the poorly understood properties of thin glassy films which find use in many technical applications
