Liquid Crystal Elastomer Actuators and Soft Robotics

Liquid crystal elastomers (LCEs) merge the orientational order of liquid crystals with the elasticity of polymer networks, producing materials that undergo large, reversible shape changes under external stimuli such as heat, light or humidity. Their anisotropic structure allows precise programming of deformation pathways, enabling bending, twisting, contraction or expansion on demand. Coupled with advances in fabrication—ranging from direct laser writing to layer-by-layer assembly—LCE actuators can be sculpted into complex architectures and integrated into untethered soft robots. These systems harness remote, contactless control and often combine photochemical and photothermal responses to achieve autonomous motion, object manipulation and energy harvesting. The global significance of this field lies in its potential for minimally invasive medical devices, adaptive prosthetics, micro-robotics, and environmentally powered machines that mimic the sophistication of biological systems.

Research from Nature Portfolio

Recent studies have demonstrated autonomous soft devices that couple optical sensing with photomechanical actuation. A light-driven artificial flytrap uses LCEs at the tip of an optical fibre to detect and capture targets through self-regulated closure, mimicking the rapid movements of botanical carnivores. Layered LCE actuators have been engineered to enhance out-of-plane work capacity by integrating multiple thin films via directed self-assembly and adhesive interfaces, achieving force outputs an order of magnitude higher than single-layer counterparts. Multi-wavelength modulated soft walkers exploit selective stimulation of hierarchical LCE domains under visible and near-infrared light bands to execute multi-directional movements and diverse shape-morphing modes without reliance on scanning or mechanical linkages.

Research from all publishers

Electrochemical artificial yarn muscles employ a dual-ion co-regulation strategy to shorten ion migration pathways, yielding high contractile strokes exceeding 30% and rapid response rates above 9% per second. These yarn actuators achieve isometric stresses far beyond skeletal muscles and can maintain tension in an energy-free catch state. In another advance, bilayer electrothermal actuators based on graphite–carbon nanotube hybrid films integrate self-sensing capabilities with actuation. By tuning the conductive network, these devices concurrently generate bending motions under Joule heating and monitor displacement in real time, enabling feedback-driven control and the discrimination of soft versus rigid contacts without additional sensors.

Liquid Crystal Elastomer Actuators and Soft Robotics publication trend

The graph below shows the total number of articles in liquid crystal elastomer actuators and soft robotics across all publications each year (not limited to Nature Index journals).

Technical terms

Liquid crystal elastomer (LCE): A polymer network combining liquid crystalline order with rubber elasticity, capable of reversible, stimulus-responsive shape change.

Photothermal effect: The conversion of absorbed light into heat within a material, triggering thermally induced actuation.

Photochemical isomerisation: A light-driven molecular transformation that alters polymer microstructure to induce macroscopic deformation.

Catch state: A high-tension configuration of an actuator that sustains load without continuous energy input.

Self-sensing actuator: An active device that integrates sensing and actuation functions, providing real-time feedback on deformation or external forces.

References

1. A light-driven artificial flytrap. Nature Communications (2017).
2. Layered liquid crystal elastomer actuators. Nature Communications (2018).
3. Visible and infrared three-wavelength modulated multi-directional actuators. Nature Communications (2019).
4. Dual-Ion Co-Regulation System Enabling High-Performance Electrochemical Artificial Yarn Muscles with Energy-Free Catch States. Nano-Micro Letters (2023).
5. Self‐Sensing Paper Actuators Based on Graphite–Carbon Nanotube Hybrid Films. Advanced Science (2018).