Wenzhou Key Laboratory of Biomaterials and Engineering, Wenzhou Institute, University of Chinese Academy of Sciences, 325000, Wenzhou, Zhejiang, China.
School of Physical Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China.
Nat Commun. 2023 May 15;14(1):2773. doi: 10.1038/s41467-023-38461-1.
Colloidal gels are widely applied in industry due to their rheological character-no flow takes place below the yield stress. Such property enables gels to maintain uniform distribution in practical formulations; otherwise, solid components may quickly sediment without the support of gel matrix. Compared with pure gels of sticky colloids, therefore, the composites of gel and non-sticky inclusions are more commonly encountered in reality. Through numerical simulations, we investigate the gelation process in such binary composites. We find that the non-sticky particles not only confine gelation in the form of an effective volume fraction, but also introduce another lengthscale that competes with the size of growing clusters in gel. The ratio of two key lengthscales in general controls the two effects. Using different gel models, we verify such a scenario within a wide range of parameter space, suggesting a potential universality in all classes of colloidal composites.
胶态凝胶由于其流变特性（屈服应力以下不流动）而被广泛应用于工业领域。这种特性使得凝胶在实际配方中能够保持均匀的分布；否则，没有凝胶基质的支撑，固体成分可能会迅速沉淀。因此，与纯粘性胶体凝胶相比，凝胶和非粘性夹杂的复合材料在现实中更为常见。通过数值模拟，我们研究了这种二元复合材料的凝胶化过程。我们发现，非粘性颗粒不仅以有效体积分数的形式限制凝胶化，而且还引入了另一个与凝胶中生长簇大小竞争的长度尺度。这两个关键长度尺度的比值通常控制着这两个效应。使用不同的凝胶模型，我们在广泛的参数空间内验证了这种情况，这表明在所有胶体复合材料中都存在潜在的普遍性。
