# Liquid Marble Photosensor

## TL;DR

This paper presents a novel liquid marble-based photosensor utilizing the Belousov-Zhabotinsky reaction, demonstrating light-responsive electrical oscillations suitable for applications in liquid electronics and soft robotics.

## Contribution

It introduces a new type of photosensor made from BZ liquid marbles with electrodes, showing how light affects their electrical oscillations, a novel approach in soft, liquid-based sensing.

## Key findings

- Light inhibits oxidation wave-fronts in BZ liquid marbles.
- Electrode potential oscillates due to chemical waves.
- Potential applications in liquid electronics and soft robotics.

## Abstract

A liquid marble is a liquid droplet coated by a hydrophobic power. The liquid marble does not wet adjacent surfaces and therefore can be manipulated as a dry soft body. A Belousov-Zhabotinsky (BZ) reaction is an oscillatory chemical reaction exhibiting waves of oxidation. We demonstrate how to make a photo-sensor from BZ medium liquid marbles. We insert electrodes into a liquid marble, prepared from BZ solution and coated with polyethylene powder. The electrodes record a potential difference which oscillates due to oxidation wave-fronts crossing the electrodes. When the BZ marble is illuminated by a light source, the oxidation wave-fronts are hindered and, thus, the electrical potential recorded ceases to oscillate. We characterise several types of responses of BZ marble photosensors to various stimuli, and provide explanations of the recorded activity. BZ liquid marble photosensors may find applications in the fields of liquid electronics, soft robotics and unconventional computing.