压力下胶体玻璃的动力学各向异性
Dynamical Anisotropy of a Colloidal Glass Under Pressure
查看机构详情
- The Institute for Advanced Studies, Wuhan University（武汉大学高等研究院）
- Department of Physics, Wenzhou University（温州大学物理系）
机构由 AI 辅助整理，请以论文原文为准。
浏览论文内容
中文总结 AI 辅助
本研究通过毛细管中胶体玻璃施加压力，首次揭示压力下动力学各向异性（平行方向运动更快），并发现动力学冻结而结构变化温和，为玻璃制造提供设计原则。
中文摘要 AI 辅助
压力是深刻影响玻璃物理性质的关键热力学参数。压力诱导的致密化和结构转变赋予了在此条件下制造的玻璃优异的力学和光学性能。尽管压力处理过的玻璃已通过X射线衍射和拉曼光谱等系综平均方法进行了表征，但其微观动力学却很少被研究，这限制了我们对结构、动力学和力学之间耦合的理解。在此，我们使用限制在圆柱形毛细管中的二元硬球胶体玻璃，通过重力的切向分量对颗粒施加恒定压力。该方法首次实现了对压力对胶体玻璃影响的研究。我们发现动力学被显著冻结，而结构变化相对温和。在低压下，观察到结构、动力学和局部弹性异质性之间的空间相关性。值得注意的是，动力学各向异性在压力响应中出现，其特征是平行于压力方向的运动快于垂直于压力方向的运动。这种各向异性归因于强压力力引起的不稳定性。同时，结构和动力学异质性在压力下被强烈抑制。我们的实验表征了压力下胶体玻璃的微观动力学，并为玻璃材料的制造工艺提供了设计原则。
英文摘要
Pressure is a critical thermodynamic parameter that profoundly influences the physical properties of glasses. Pressure-induced densification and structural transformation endow glasses manufactured under such conditions with exceptional mechanical and optical properties. Although pressure-treated glasses have been characterized by ensemble-averaged methods such as X-ray diffraction and Raman spectroscopy, their microscopic dynamics have rarely been addressed, limiting our understanding of the coupling among structure, dynamics, and mechanics. Here, using a binary hard-sphere colloidal glass confined in cylindrical capillary tubes, we impose a constant pressure on the particles through the tangential component of gravity. This approach enables the first investigation of pressure effects on colloidal glasses. We find that the dynamics are substantially frozen, whereas the structural change remains comparatively mild. At low pressure, spatial correlations among structural, dynamical, and local elastic heterogeneities are observed. Remarkably, dynamical anisotropy emerges in response to pressure, characterized by faster motion parallel to the pressure direction than perpendicular to it. This anisotropy is attributed to an instability induced by the strong pressure force. Concurrently, structural and dynamical heterogeneities are strongly suppressed under pressure. Our experiments characterize the microscopic dynamics of colloidal glasses under pressure and offer design principles for the manufacturing protocol of glass materials.
