Origin and Control of Kinetic and Thermodynamic Hysteresis in Clustering of Gold Nanoparticles

Hysteresis is an essential attribute of many solid-state devices and biological processes, yet it is often overlooked in colloidal and soft-matter dynamic systems. Herein we show that gold nanoparticles can remain dispersed or aggregated at the same temperature depending on the trajectory of applied stimulus, featuring hysteretic behaviour. Aided by real-time analytics and fine tuning of experimental parameters, such as salt concentration, nanoparticle diameter and surface potential, we disentangled kinetic (rate-dependent) and thermodynamic (rate-independent) component of hysteresis in cyclic clustering of nanoparticles. The hysteresis originates from the difference in the aggregation and disassembly temperatures. Our findings enrich the repertoire of experimental framework suitable for study life-like features on purely synthetic settings.