The role of extracted free chains in adhesion on soft gel surfaces可提取自由链在软凝胶表面黏附中的作用

Abstract摘要

Adhesion on soft polymeric materials involves large deformations and transport within the polymer network. Using dual-wavelength confocal microscopy, this work characterizes contact-induced extraction of free chains and the adhesion profiles of microspheres placed on silicone gels with different crosslinking densities. The measurements reveal a locally phase-separated region near the contact while the surface-stress balance remains well defined. At the global scale, indentation depth and contact radius follow the competition between adhesion energy and surface stress captured by classical contact models. A slow increase in indentation over time further points to a gradual rise in adhesion energy on a poroelastic diffusion timescale.

软聚合物材料的黏附伴随着大变形以及聚合物网络内部的物质迁移。本研究利用双波长共聚焦显微镜，研究不同交联密度硅凝胶上微球接触引起的自由链提取与黏附形貌。结果显示，接触区域附近会形成局部相分离区，同时表面应力平衡仍然清晰可辨；在宏观尺度上，压入深度和接触半径由黏附能与表面应力之间的竞争决定。压入深度随时间缓慢增加，说明黏附能会在孔弹性扩散时间尺度上逐步增长。