Active embracement enables autonomous tweezing in active star polymers
Abstract
The capacity for autonomous structural reconfiguration is a defining trait of living systems, yet it remains elusive in artificial active matter. Here, we report the discovery of active embracement, a non-equilibrium phenomenon where active star polymers, comprising a central core and self-propelled monomeric arms, transition from open configurations to tightly collapsed, ``hugging'' states. By combining polymer experiments using connected vibrobots with simulations, we demonstrate that internal self-propulsion fundamentally overrides the steric repulsion that keeps passive polymers dispersed. This active drive enables a suite of behaviors unattainable in equilibrium systems: individual star polymers undergo a globular-like self-collapse, multiple star polymers mutually intertwine and mutually embrace, and can spontaneously embrace and capture surrounding passive particles. Our findings reveal that active embracement is a distinct kinetic phase that allows star polymers to function as autonomous tweezers. By bridging the gap between macroscopic robotic collectives and microscopic polymer physics, this work provides a versatile blueprint for the design of smart materials capable of targeted cargo capture and self-directed assembly in complex environments.
Related
- Strain Waves Generate Compression and Trigger Buckling in Active Polymers
- Emergent Active-Blob Length Scale Governs the Collapse Transition of Tangentially Driven Polymers
- Active Self-Consistent Field Theory for Ornstein-Uhlenbeck Polymers
- Self-Avoidance Governs Re-entrant Coil-Globule Transition of Inertial Active Brownian Ring Polymers
- Polarity-Programmed Topological Gating of Knotting in Spatially Patterned Active Polymers
BibTeX
@misc{musacchio2026active,
title = {{Active embracement enables autonomous tweezing in active star polymers}},
author = {Marco Musacchio and Davide Breoni and Iman Abdoli and Luca Tubiana and Hartmut Löwen and Lorenzo Caprini},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.29728},
eprint = {2608.29728},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.29728},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Active embracement enables autonomous tweezing in active star polymers
AU - Marco Musacchio
AU - Davide Breoni
AU - Iman Abdoli
AU - Luca Tubiana
AU - Hartmut Löwen
AU - Lorenzo Caprini
PY - 2026
DA - 2026/08/30
PB - arXiv
DO - 10.48550/arxiv.2608.29728
UR - https://arxiv.org/abs/2608.29728
AB - The capacity for autonomous structural reconfiguration is a defining trait of living systems, yet it remains elusive in artificial active matter. Here, we report the discovery of active embracement, a non-equilibrium phenomenon where active star polymers, comprising a central core and self-propelled monomeric arms, transition from open configurations to tightly collapsed, ``hugging'' states. By combining polymer experiments using connected vibrobots with simulations, we demonstrate that internal self-propulsion fundamentally overrides the steric repulsion that keeps passive polymers dispersed. This active drive enables a suite of behaviors unattainable in equilibrium systems: individual star polymers undergo a globular-like self-collapse, multiple star polymers mutually intertwine and mutually embrace, and can spontaneously embrace and capture surrounding passive particles. Our findings reveal that active embracement is a distinct kinetic phase that allows star polymers to function as autonomous tweezers. By bridging the gap between macroscopic robotic collectives and microscopic polymer physics, this work provides a versatile blueprint for the design of smart materials capable of targeted cargo capture and self-directed assembly in complex environments.
ER -