Variable Stiffness Fiber with Self-Healing Capability.

Alice Tonazzini,Barbara Mazzolai,Bryan Schubert,Stefano Mintchev,Jun Shintake,Dario Floreano

doi:10.1002/adma.201602580

Abstract

A variable stiffness fiber made of silicone and low melting point alloys quickly becomes >700 times softer and >400 times more deformable when heated above 62 °C. It shows remarkable self-healing properties and can be clamped, knitted, and bonded, as shown in a foldable multi-purpose drone, a wearable cast for bone injuries, and a soft multi-directional actuator.

Highlights

Soft hardware technologies[1] are increasingly used in structures, actuators, and robots intended for unstructured environments,[2] user safety,[3] and tasks requiring high dexterity or conformability such as manipulation,[4,5,6] locomotion,[7] rehabilitation, and surgical operations.[8]
The outstanding features of Low melting point alloys (LMPA) have been exploited in the form of multi-layered composites,[24] metallic microstructures embedded in soft elastomers,[25] and metal–elastomer foams.[26]
The latter can become 20–30 times softer, 200 times more deformable, and it can self-heal when the internal metallic mesh is melted by an external heat source, large structures raise the issue of melting the entire volume (e.g., a 27 × 27 × 9 mm3 cuboid required 500 °C air blown for almost 80 s).[26]

Summary

Introduction

Soft hardware technologies[1] are increasingly used in structures, actuators, and robots intended for unstructured environments,[2] user safety,[3] and tasks requiring high dexterity or conformability such as manipulation,[4,5,6] locomotion,[7] rehabilitation, and surgical operations.[8]. When the LMPA melting temperature (Tm = 62 °C) is reached, the LMPA core transitions from solid (stiff) to liquid state (soft) (Text S1, Supporting information).

Results

Conclusion