Bioinspired silicone-based materials for adjustable energy dissipation in soft robotics and electronics

Description

Living systems have been engineered by nature during the course of evolution to be perfectly adapted to their environment. Often being built-up by a small range of basic materials, multilayered protective structures such as bones, skin or fruit peel that can not only sustain high dynamic, but also quasi-static mechanical loads. Taking inspiration from biological tissues we present simple approaches to tailored silicone materials with adjustable stiffness for their use in stretchable electronics and soft robotics. Silicone elastomers as rubbers are inherently dissipative, however it is still challenging to create graded elastic moduli within one structure. We therefore developed a polyimide-polydimethylsiloxane (PI-PDMS) material mimicking the mechanical properties of the beak of the Humbold squid. The squid beak bridges a wide range of mechanical properties allowing to seamlessly connect the hard beak for cracking open mussels with the soft body of the squid. In analogy, we cover a wide range of mechanical properties by tuning the amounts of the chemical components. To demonstrate the versatility of graded structures made from PI-PDMS, we demonstrate stretchable conductors, reducing principal strain at weak interfaces as well as simple dielectric elastomer actuators. In a further approach, we designed open-pore silicone foams filled with carbon black mimicking the spongy structures of citrus fruit peel. Citrus fruit peel and in particular the spongy foam called albedo is a perfectly tailored biological damping structure. It protects the citrus fruit from splitting open upon its fall from the tree and thus ensures seed distribution. We created foams inspired by citrus fruit albedo and combined them with a peel-like circular pneumatic actuator to demonstrate adjustable energy dissipation as well as sensing upon impact.

Period	03 Sept 2025
Event title	BioElectronics in FLEXible Technologies 2025
Event type	Conference
Degree of Recognition	International