近日，日本东京大学的Hajime Tanaka及其研究团队取得一项新进展。经过不懈努力，他们揭示不同弹性性质及其在玻璃和凝胶中的起源。相关研究成果已于2024年4月12日在国际知名学术期刊《自然—物理学》上发表。

该研究团队通过模拟，阐明了玻璃和凝胶中与温度、观察时间和老化相关的不同弹性特性，揭示了潜在的机制。研究发现，构型约束以振动均方位移为特征，对凝胶中的剪切模量和体积模量产生了类似的影响，但独特地作用于玻璃中的剪切模量。与凝胶不同，玻璃在老化过程中呈现出持续硬化的趋势，而凝胶则经历了一个从硬到软的转变过程。

研究人员进一步指出，这些差异源于两种非晶态固体在最小化自由能方面的不同机制：玻璃中的结构有序性和凝胶中的界面减少。这一发现不仅揭示了不同的行为，而且揭示了非平衡无序固体弹性的起源和演变，对非晶态材料的应用和设计具有重要意义。

据悉，玻璃和凝胶是常见的非晶态固体，具有多种应用，具有有趣的相似之处，例如均不具备平移序，都表现出刚性特质，以及在老化过程中动态行为逐渐减缓等。然而，它们的各种潜在差异尚未得到解释。

附：英文原文

Title: Distinct elastic properties and their origins in glasses and gels

Author: Wang, Yinqiao, Tateno, Michio, Tanaka, Hajime

Issue&Volume: 2024-04-12

Abstract: Glasses and gels, common amorphous solids with diverse applications, share intriguing similarities, including rigidity without translational order and dynamic slowing during ageing. However, their various underlying differences have not yet been explained. Here, through simulations, we elucidate distinct elastic properties related to temperature, observation times and ageing in glasses and gels, uncovering the underlying mechanisms. Configurational constraints, characterized by vibrational mean-squared displacements, similarly impact shear and bulk moduli in gels, but uniquely affect the shear modulus in glasses. As glasses age, a persistent trend of stiffening emerges, in contrast to gels, which initially stiffen and subsequently soften. We attribute these differences to mechanisms minimizing free energy: structural ordering in glasses and interface reduction in gels. Our findings not only reveal distinct behaviours but also shed light on the origin and evolution of elasticity in non-equilibrium disordered solids, with implications for amorphous material application and design.

DOI: 10.1038/s41567-024-02456-6

Source: https://www.nature.com/articles/s41567-024-02456-6