Scaling of dynamics with the range of interaction in short-range attractive colloids

TL;DR

This study numerically investigates how the dynamics of short-range attractive colloids depend on the interaction range, revealing exact scaling with thermodynamics for small ranges and insights into gel formation mechanisms.

Contribution

It demonstrates that for short-range potentials, dynamics scale with thermodynamics and gels form via kinetically arrested phase separation, extending understanding of colloid behavior.

Findings

Dynamics scale with thermodynamics for small interaction ranges.

The relative position of glass and liquid-gas lines is independent of interaction range.

Gels form only through kinetically arrested phase separation.

Abstract

We numerically study the dependence of the dynamics on the range of interaction $\Delta$ for the short-range square well potential. We find that, for small $\Delta$, dynamics scale exactly in the same way as thermodynamics, both for Newtonian and Brownian microscopic dynamics. For interaction ranges from a few percent down to the Baxter limit, the relative location of the attractive glass line and the liquid-gas line does not depend on $\Delta$. This proves that in this class of potentials, disordered arrested states (gels) can be generated only as a result of a kinetically arrested phase separation.