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arXiv · 2610.33394

Mapping bimodal colloidal depletion systems onto the monodisperse gelation phase diagram

Robert A. Campbell·Ziye Zhuang·Ali Mohraz·Safa Jamali
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Abstract

Many industries rely on models of colloidal gelation and phase behavior to predict how processing equipment will handle new product formulations. In colloidal systems with nearly uniform particle size it is possible to predict the formation of a gel from only three state variables; however, the extension of this model to bimodal and multimodal systems is not well described. Here we present a systematic simulation study of the attractive bimodal depletion gel phase diagram. For these systems, we find that gelation is highly dependent on total volume fraction, attraction conditions, and bimodal composition. Attraction and composition can be effectively collapsed into a single parameter using the contact-weighted second virial coefficient. This successfully projects the bimodal phase diagram onto the established monodisperse phase diagram, including accurately describing most bulk assembly properties; however, the underlying network structure of these gels remains highly dependent on the details of bimodal composition and attraction.

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Robert A. Campbell, Ziye Zhuang, Ali Mohraz, Safa Jamali. 2026-10-24. Mapping bimodal colloidal depletion systems onto the monodisperse gelation phase diagram. https://arxiv.org/abs/2610.33394

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