Physical Chemistry and Soft Matter, Wageningen University & Research, Wageningen, Gelderland, 6708 WE, The Netherlands.
Phys Rev Lett. 2020 Nov 13;125(20):208004. doi: 10.1103/PhysRevLett.125.208004.
Colloidal gels may experience syneresis, an increase in volume fraction through expulsion of the continuous phase. This poroelastic process occurs when adhesion to the container is weak compared to endogenous stresses which develop during gelation. In this work, we measure the magnitude of syneresis, ΔV/V_{0}, for gels composed of solid, rubber, and liquid particles. Surprisingly, despite a constant thermoresponsive interparticle potential, gels composed of liquid and elastic particles synerese to a far greater extent. We conclude that this magnitude difference arises from contrasting modes of stress relaxation within the colloidal gel during syneresis either by bending or stretching of interparticle bonds.
胶态凝胶可能会经历排液现象，即连续相的排出导致体积分数增加。当与容器的附着力相对于凝胶形成过程中产生的内源性应力较弱时，会发生这种多孔弹性过程。在这项工作中，我们测量了由固体、橡胶和液体颗粒组成的凝胶的排液量ΔV/V_0。令人惊讶的是，尽管存在恒定的热响应粒子间势能，但由液体和弹性粒子组成的凝胶排液的程度要大得多。我们得出结论，这种幅度差异是由于在排液过程中胶体凝胶内部的应力松弛模式不同，即通过粒子间键的弯曲或拉伸。
