# Flow‐Active Liquid Marbles as Microreactors for Photocatalytic Micromotors

## TL;DR

Researchers developed liquid marbles with micromotors that move faster and transfer mass better under light, offering a new platform to study active matter and reactions.

## Contribution

Integration of light-driven micromotors with liquid marbles to enhance mobility and mass transfer in a transparent, soft-confinement platform.

## Key findings

- Partially covered liquid marbles increase micromotor velocity by threefold compared to sessile droplets.
- Photocatalytic propulsion under illumination enhances micromotor dispersion and mass transfer.
- The platform enables study of active particles and reactions at curved liquid–air interfaces.

## Abstract

Self‐propelled micromotors have shown promise for applications in environmental remediation, sensing, and biomedicine. However, assessing their performance in realistic, 3D microenvironments with dynamic boundaries and complex topography remains a key challenge. Achieving controlled motion and enhanced reactivity under such confinement is critical for both technological applications and fundamental studies on active matter. Here, the integration of light‐driven micromotors with liquid marbles is presented, which are gas‐permeable droplets encased by hydrophobic particles that act as dynamic, flow‐active microreactors. By tuning the coverage of the particulate shell, partially covered liquid marbles are developed that exhibit robust evaporation‐induced flows, increasing the average micromotor velocity by approximately threefold compared to sessile droplets. Under illumination, photocatalytic self‐propulsion provides an additional velocity component and promotes micromotor dispersion. The combined circulation enhances mass transfer, guiding micromotor accumulation and transport while providing an optical transparent, soft‐confinement platform for studying active particles and confined catalytic reactions.

Light‐powered micromotors inside partially covered liquid marbles couple photocatalysis with flow‐driven transport, achieving higher mobility and enhanced mass transfer. This soft, transparent confinement platform offers a new route to study active matter and catalytic processes at curved liquid–air interfaces.