# C. elegans-inspired undulatory motion in a light-driven liquid crystal elastomer fiber

## TL;DR

Researchers created a light-controlled soft robot that moves like a worm underwater by mimicking C. elegans motion.

## Contribution

A light-driven LCE fiber that replicates C. elegans-inspired undulatory motion with programmable control.

## Key findings

- A millimeter-scale LCE fiber achieves stable figure-eight-like motion underwater.
- Undulatory movement is enabled by sequential laser excitation with a 45-degree phase delay.
- Actuation performance scales with fiber length, allowing amplitude tuning and directional control.

## Abstract

Undulatory movement is widely observed in the animal kingdom, from snakes and earthworms to microorganisms. Mimicking such deformation is important in soft robotics in terms of locomotion control and navigation efficiency. However, realizing such motion at miniature scales in fluid environments remains difficult for soft actuators. Here, we present light-controlled undulatory motion inspired by C. elegans, realized in a millimeter-scale liquid crystal elastomer (LCE) fiber actuator under water. We use the sequential excitation of four laser beams to generate bimorphic actuation between two segments of the LCE, with a 45-degree phase delay between two consequent deformation phases. The actuator demonstrates stable figure-eight-like trajectories and directional steering through laser power modulation. Furthermore, the actuation performance scales with fiber length, providing amplitude tuning and demonstrating programmable control of locomotion.

•A centimeter-long liquid crystal elastomer fiber exhibits worm-like underwater locomotion•Sequential four-beam excitations enable undulatory motion mimicking C. elegans•The phase and segmental location of deformation can be programmed by light

A centimeter-long liquid crystal elastomer fiber exhibits worm-like underwater locomotion

Sequential four-beam excitations enable undulatory motion mimicking C. elegans

The phase and segmental location of deformation can be programmed by light

Applied sciences; Biomaterials