Zaccone Alessio, Noirez Laurence
Department of Physics "A. Pontremoli", University of Milan, 20133 Milan, Italy.
Department of Chemical Engineering and Biotechnology, University of Cambridge, CB30AS Cambridge, U.K.
J Phys Chem Lett. 2021 Jan 14;12(1):650-657. doi: 10.1021/acs.jpclett.0c02953. Epub 2021 Jan 4.
Liquids confined to sub-millimeter scales have remained poorly understood. One of the most striking effects is the large elasticity revealed using good wetting conditions, which grows upon further decreasing the confinement length, . These systems display a low-frequency shear modulus in the order of 1-10 Pa, contrary to our everyday experience of liquids as bodies with a zero low-frequency shear modulus. While early experimental evidence of this effect was met with skepticism and abandoned, further experimental results and, most recently, a new atomistic theoretical framework have confirmed that liquids indeed possess a finite low-frequency shear modulus ', which scales with the inverse cubic power of confinement length . We show that this law is universal and valid for a wide range of materials (liquid water, glycerol, ionic liquids, non-entangled polymer liquids, isotropic liquids crystals). Open questions and potential applications in microfluidics mechanochemistry, energy, and other fields are highlighted.
局限于亚毫米尺度的液体一直未得到充分理解。其中最显著的效应之一是在良好的润湿条件下所揭示的大弹性，这种弹性会随着限制长度的进一步减小而增大。这些系统呈现出约1 - 10帕斯卡量级的低频剪切模量，这与我们日常所体验的液体作为低频剪切模量为零的物体的认知相反。虽然这种效应的早期实验证据曾遭到怀疑并被摒弃，但进一步的实验结果以及最近一个新的原子理论框架证实，液体确实拥有有限的低频剪切模量，其与限制长度的立方反比成比例。我们表明，这条定律具有普遍性，适用于多种材料（液态水、甘油、离子液体、非缠结聚合物液体、各向同性液晶）。文中还强调了在微流体力学、机械化学、能源及其他领域的开放性问题和潜在应用。
