论文标题
三个长度尺度胶体凝胶：簇的簇与互穿簇接近
Three length scales colloidal gels: the clusters of clusters versus the interpenetrating clusters approach
论文作者
论文摘要
通常，在静止的条件下，低体积分数的有吸引力的胶体形成分形凝胶，分为两个长度尺度：胶体和分形簇尺度。但是，当流动干扰凝胶化胶体分形凝胶时，可能会显示三个不同的长度尺度[Dagès等人，软物质18，6645（2022）]。在最近的实验研究之后，我们得出了两个模型，这些模型解释了这种非典型胶体凝胶的结构和流变特性。凝胶弹性是通过缩放参数推断出来的，结构被转化为散射强度，遵循Beaucage提出的全局散射函数方法，通常以小角度X射线散射（SAXS）进行测量。在这两种模型中，我们都认为胶体将凝结成分形簇。在簇模型的簇中，簇形成超级品牌，然后构建凝胶网络。在互穿簇模型中，簇插入式渗透构成单位以形成凝胶网络。然后，利用这两个模型来分析通过流动戒烟形成的碳黑凝胶进行的Rheo-saxs实验。随着凝胶特征长度尺度的增加，分析结果对簇模型的簇进行了质量化。
Typically, in quiescent conditions, attractive colloids at low volume fractions form fractal gels structured into two length scales: the colloidal and the fractal cluster scales. However when flow interfere with gelation colloidal fractal gels may display three distinct length scales [Dagès, et al., Soft Matter 18, 6645 (2022)]. Following those recent experimental investigations, we derive two models that account for the structure and the rheological properties of such atypical colloidal gels. The gel elasticity is inferred from scaling arguments and the structure is translated into scattering intensities following the global scattering functions approach proposed by Beaucage and typically measured in small angle X-ray scattering (SAXS). In both models, we consider that the colloids condensate into fractal clusters. In the clusters of clusters model, the clusters form superagregates which then build the gel network. In the interpenetrating clusters model, the clusters interpenetrate one-another to form the gel network. Those two models are then utilised to analyse rheo-SAXS experiments carried out on carbon black gels formed through flow cessation. The results of the analysis vouch for the clusters of clusters model with a densification of the structures as the gel characteristic length scales increase.
