Observation and Characterization of the Vestige of the Jamming Transition in a Thermal 3D System

TL;DR

This study investigates how pair correlations and particle mobility change with packing density in a 3D soft colloid system, revealing a thermal remnant of the jamming transition in experimental data.

Contribution

It provides experimental evidence of the vestige of the jamming transition in a thermal colloidal system through analysis of pair correlation functions.

Findings

Peak in the first peak of g(r) correlates with particle arrest.

g(r) remains liquid-like across all packing fractions.

Identifies a thermal remnant of the zero-temperature jamming divergence.

Abstract

We study the dependence of the pair-correlation function, $g(r)$, and particle mobility on packing fraction in a dense three-dimensional packing of soft colloids made of poly N-isopropyl acrylamide (pNIPAM), a thermo-sensitive gel. We find that $g(r)$ for our samples is qualitatively like that of a liquid at all packing fractions. There is a peak in $g_{1}$, the height of the first peak of $g(r)$, as a function of packing fraction. This peak is identified as the thermal remnant of the T=0 divergence found at the jamming transition in simulations of soft frictionless spheres at zero-temperature. Near where there is a peak in $g_{1}$ the particles become arrested on the time scale of the experiment.