Active Micro/Nanoparticles in Colloidal Microswarms

Abstract

Colloidal microswarms have attracted increasing attention in the last decade due to their unique capabilities in various complex tasks. Thousands or even millions of tiny active agents are gathered with distinctive features and emerging behaviors, demonstrating fascinating equilibrium and non-equilibrium collective states. In recent studies, with the development of materials design, remote control strategies, and the understanding of pair interactions between building blocks, microswarms have shown advantages in manipulation and targeted delivery tasks with high adaptability and on-demand pattern transformation. This review focuses on the recent progress in active micro/nanoparticles (MNPs) in colloidal microswarms under the input of an external field, including the response of MNPs to external fields, MNP–MNP interactions, and MNP–environment interactions. A fundamental understanding of how building blocks behave in a collective system provides the foundation for designing microswarm systems with autonomy and intelligence, aiming for practical application in diverse environments. It is envisioned that colloidal microswarms will significantly impact active delivery and manipulation applications on small scales.

Self-Diffusiophoresis and Symmetry-Breaking of a Janus Dimer: Analytic Solution

“…The subject of autophoretic mobility of active colloids (rigid or deformable) continues to attract attention within the nano-technology community, for example, in recent reviews [1,2]. Among the various physical/chemical mechanisms related to the selfpropulsion problem of freely suspended micron-size particles in an unbounded solute in the absence of any external forcing [3][4][5], we chose here self-diffusiophoresis as an archetypal problem [6][7][8]. Within this framework, particle mobility is deduced by a symmetry-breaking effect resulting from different types of surface on the two spheres.…”