2026-04-14T02:49:43Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1926462025-12-04T20:47:33Zcom_2072_1057col_2072_478822col_2072_478917

00925njm 22002777a 4500 dc De Corato, Marco author Pagonabarraga Mora, Ignacio author 2023-01-26T11:47:28Z 2023-11-13T06:10:20Z 2022-11-13 2023-01-26T11:47:28Z Similar to cells, bacteria, and other micro-organisms, synthetic chemically active colloids can harness the energy from their environment through a surface chemical reaction and use the energy to self-propel in fluidic environments. In this paper, we study the chemo-mechanical coupling that leads to the self-propulsion of chemically active colloids. The coupling between chemical reactions and momentum transport is a consequence of Onsager reciprocal relations. They state that the velocity and the surface reaction rate are related to mechanical and chemical affinities through a symmetric matrix. A consequence of Onsager reciprocal relations is that if a chemical reaction drives the motion of the colloid, then an external force generates a reaction rate. Here, we investigate Onsager reciprocal relations for a spherical active colloid that catalyzes a reversible surface chemical reaction between two species. We solve the relevant transport equations using a perturbation expansion and numerical simulations to demonstrate the validity of reciprocal relations around the equilibrium. Our results are consistent with previous studies and highlight the key role of solute advection in preserving the symmetry of the Onsager matrix. Finally, we show that Onsager reciprocal relations break down around a nonequilibrium steady state, which has implications for the thermal fluctuations of the active colloids used in experiments. Termodinàmica del desequilibri Matèria condensada tova Col·loides Nonequilibrium thermodynamics Soft condensed matter Colloids Onsager reciprocal relations and chemo-mechanical coupling for chemically-active colloids