Activity-Induced Structural and Dynamical Heterogeneity in Colloidal Gels
Abstract
Active gels are intrinsically non-equilibrium materials whose structural and dynamical heterogeneity emerges from the interplay of attractive interactions, thermal fluctuations, and self-propulsion. We investigate a model active gel, simulated using large-scale Brownian dynamics simulations, to explore the effects of temperature T, active force strength f0, persistence timescale τp, and active particle concentration ρa. We characterize the structure of the evolving gel network through morphological analysis, while dynamical changes are quantified by the relaxation timescale and dynamical heterogeneity (DH). We show that an optimal choice of activity parameters yields a percolating gel network with faster gelation and larger voids and clusters, enhancing mechanical stability. Conversely, the structural relaxation timescale and DH decrease with increasing activity, indicating enhanced particle rearrangements and reduced spatial correlations of mobile and immobile regions. An effective temperature (Teff) framework for colloidal gels maps structural quantities and relaxation timescales in an active gel onto those of a passive gel. More interestingly, the growth of DH with increasing swim force can also be described by the same effective-temperature framework, in stark contrast to observations in active glasses. Our findings show that, in colloidal gels, temperature and active force compete, giving rise to similar structural ordering and, consequently, similar DH at the same Teff. These findings highlight the crucial role of structural ordering in governing DH in active colloidal gels, as compared to active glasses.
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BibTeX
@misc{nath2026activityinduced,
title = {{Activity-Induced Structural and Dynamical Heterogeneity in Colloidal Gels}},
author = {Santu Nath and Sudipta Mandal and Smarajit Karmakar},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.16553},
eprint = {2610.16553},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.16553},
}
RIS
TY - UNPB
TI - Activity-Induced Structural and Dynamical Heterogeneity in Colloidal Gels
AU - Santu Nath
AU - Sudipta Mandal
AU - Smarajit Karmakar
PY - 2026
DA - 2026/10/12
PB - arXiv
DO - 10.48550/arxiv.2610.16553
UR - https://arxiv.org/abs/2610.16553
AB - Active gels are intrinsically non-equilibrium materials whose structural and dynamical heterogeneity emerges from the interplay of attractive interactions, thermal fluctuations, and self-propulsion. We investigate a model active gel, simulated using large-scale Brownian dynamics simulations, to explore the effects of temperature T, active force strength f_0, persistence timescale τ_p, and active particle concentration ρ_a. We characterize the structure of the evolving gel network through morphological analysis, while dynamical changes are quantified by the relaxation timescale and dynamical heterogeneity (DH). We show that an optimal choice of activity parameters yields a percolating gel network with faster gelation and larger voids and clusters, enhancing mechanical stability. Conversely, the structural relaxation timescale and DH decrease with increasing activity, indicating enhanced particle rearrangements and reduced spatial correlations of mobile and immobile regions. An effective temperature (T_eff) framework for colloidal gels maps structural quantities and relaxation timescales in an active gel onto those of a passive gel. More interestingly, the growth of DH with increasing swim force can also be described by the same effective-temperature framework, in stark contrast to observations in active glasses. Our findings show that, in colloidal gels, temperature and active force compete, giving rise to similar structural ordering and, consequently, similar DH at the same T_eff. These findings highlight the crucial role of structural ordering in governing DH in active colloidal gels, as compared to active glasses.
ER -