Emergence and growth dynamics of wetting-induced phase separation on soft solids软固体表面润湿诱导相分离的产生与生长动力学

Abstract摘要

Liquid droplets on soft solids deform the substrate and create wetting ridges, but the divergent contact-point geometry and the multiphase nature of reticulated gels are difficult for conventional continuum descriptions. We report in-situ observations of the emergence and growth of wetting-induced phase separation. Migration of free chains inside the polymer network regularizes the stress singularity at the contact line. An Onsager-variational phenomenological model describes the extraction dynamics and the crossover from short-time diffusion to long-time equilibrium. Experiments with different crosslinking densities further show that intrinsic material parameters control the rate and evolution of the phase-separated region.

软固体上的液滴会使基底发生变形并形成润湿脊，但接触点的发散几何特征以及网状凝胶的多相性质，使传统连续介质理论难以直接描述。本研究原位观察了润湿诱导相分离的产生与生长过程，发现聚合物网络中的自由链迁移能够缓解接触线处的应力奇异性。基于 Onsager 变分原理建立的唯象模型，描述了自由链提取动力学以及从短时间扩散到长时间平衡的跨越。不同交联密度实验进一步表明，材料自身参数决定了相分离区域的演化速率与过程。