# Morphodynamics of surface-attached active drops

## TL;DR

The paper explores how surface-attached active drops can form various stable shapes and flows, offering new insights for designing active materials.

## Contribution

The study reveals new stable states and quantitative principles for controlling surface-attached active drops beyond previous thin-drop models.

## Key findings

- Surface-attached active drops can form diverse stable shapes and internal flows.
- Quantitative principles predict and control these states based on boundary conditions and active stresses.
- Findings provide design principles for next-generation active materials.

## Abstract

Many biological and synthetic systems are suspensions of oriented actively-moving components. Unlike in passive suspensions, the interplay between orientational order, active flows, and interactions with boundaries gives rise to fascinating new phenomena in such active suspensions. Here, we examine the paradigmatic example of a surface-attached drop of an active fluid (an “active drop”), which has so far only been studied in the idealized limit of thin drops. We find that such surface-attached active drops can exhibit a wide array of stable steady-state shapes and internal flows that are far richer than those documented previously, depending on boundary conditions and the strength of active stresses. Our analysis uncovers quantitative principles to predict and even rationally control the conditions under which these different states arise—yielding design principles for next-generation active materials.

Active matter systems, which include biological and synthetic components that consume energy to generate motion, exhibit complex behaviors influenced by their interactions with boundaries. This study reveals that surface-attached active drops can adopt a diverse range of stable shapes and internal flows, significantly expanding our understanding of their morphodynamics and providing insights for the design of advanced active materials.