Oxford Colloid Group

Department of Chemistry University of Oxford

A gel is a complex fluid consisting of two or more phases typically composed of a solid dispersed in a liquid. The majority of their mass is that of the liquid, yet they exhibit the properties of a solid, such as a non-zero yield stress. These remarkable traits can be attributed to the formation of a space spanning or percolating network constructed from the solid components and interplay between this structure and the fluid. Due to their unique properties, these materials are of commercial significance and academic interest. Our research investigates the properties, structures and dynamics of colloidal gels.

Many different pathways exist to the formation of a colloidal gel, but universally, an arrested state occurs after a period of time. The pathway depends on the system's initial configuration. We are interested colloid-polymer mixtures and the depletion interaction, with a focus on quasi-two-dimensional systems. We measure the pair potential between two particles, examine aggregation processes by way of individual particle coordination number and look at the deformation and recovery of arrested networks using optical tweezers and applied magnetic fields.

Formation of a gel in a colloid-polymer system

Particle aggregation with coordination numbers tracked over time. 

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