Butterfly proboscis-inspired tight rolling tapered soft actuators

Area of Science:

• Materials Science
• Polymer Science
• Soft Matter Physics

Background:

• Liquid crystalline networks (LCNs) are stimuli-responsive polymers capable of actuation.
• Previous LCN actuators exhibited limited bending angles.
• The design of LCN actuators can influence their performance.

Purpose of the Study:

• To investigate the potential of tapered thickness in LCN films for enhanced actuation.
• To achieve significantly larger bending and rolling capabilities in LCN actuators.
• To explore thermal and light-triggered actuation mechanisms in these novel films.

Main Methods:

• Fabrication of thin films with precisely controlled tapered thicknesses from liquid crystalline networks.
• Experimental testing of film response to thermal and light stimuli.
• Finite element analysis (FEA) to simulate the behavior of functionally graded thin films with tapered thicknesses.

Main Results:

• Tapered LCN films demonstrated the ability to roll up extremely tightly, achieving several hundreds of degrees of curl.
• The observed rolling behavior significantly surpassed the limited bending previously reported for LCN actuators.
• FEA simulations of tapered, functionally graded films showed strong agreement with experimental observations.

Conclusions:

• Tapered thickness is a highly effective design strategy for enhancing the actuation performance of LCN films.
• These findings open new possibilities for LCNs in applications requiring large-amplitude mechanical motion.
• The combination of experimental and computational methods validates the design principles for advanced LCN actuators.