# Self-assembly of colloidal molecules due to self-generated flow

## TL;DR

This paper demonstrates that self-generated solvent flow can induce long-range attractions among colloids, leading to the formation of molecule-like clusters with dynamic behaviors influenced by flow symmetry, revealing new mechanisms for colloidal self-assembly.

## Contribution

It introduces a novel mechanism where self-generated flow causes colloidal aggregation and cluster formation, expanding understanding of colloidal self-assembly processes.

## Key findings

- Flow-induced attractions extend to millimeter-range distances.
- Clusters exhibit molecule-like formation and fusion behaviors.
- Flow symmetry breaking can activate cluster dynamics.

## Abstract

The emergence of structure through aggregation is a fascinating topic and of both fundamental and practical interest. Here we demonstrate that self-generated solvent flow can be used to generate long-range attractions on the colloidal scale, with sub-pico Newton forces extending into the millimeter-range. We observe a rich dynamic behavior with the formation and fusion of small clusters resembling molecules, the dynamics of which is governed by an effective conservative energy that decays as $1/r$. Breaking the flow symmetry, these clusters can be made active.