Novel Conductive, Self-Healing 'Supergel' Could Optimize Flexible Electronics

October 8, 2015

Texas Engineers in the Department of Mechanical Engineering have developed a conductive, self-healing hybrid gel with high conductivity and strong mechanical and electrical self-healing properties that do not require external stimuli.

UT Austin Researchers:
Ye Shi, Mechanical Engineering graduate student
Yaqun Wang, Mechanical Engineering visiting scholar
Guihua Yu, Mechanical Engineering assistant professor

Discovery: A conductive, self-healing hybrid gel consisting of nanostructured conductive polymer and metal-ligand supramolecules. 

Until now, self-healing materials have relied on external stimuli such as light or heat to activate self-healing. This “supergel” material has high conductivity and strong mechanical and electrical self-healing properties that do not require external stimuli.

Why It Matters: The hybrid gel could be applied in many technologies where conductive, self-healing materials are required, such as flexible electronics, implantable biosensors, artificial skins and energy devices. 

How It Works: The researchers created a hybrid gel system with nanostructured polypyrrole (PPy) — a conductive polymer — gel enabling a 3-D network to transport electrons and enhancing mechanical reinforcement, combined with supramolecular gel to contribute to the hybrid gel’s self-healing property and conductivity. 

They built up the cubic architecture of supramolecular gel by combining two components: 2, 2’:6’, 2”-terpyridine (tpy) and Zn(II) atoms. Tpy molecules act as the framework (the edges of cubes) and Zn(II) atoms “glue” them together. As a result, the supramolecular gel can change from a solution state to hard gel. This unique property enabled the introduction of the supramolecular gel into the conductive PPy matrix (the solution can infiltrate into PPy matrix and then turn to hard gel), resulting in the supergel material.

Published: Nano Letters, “A Conductive Self-Healing Hybrid Gel Enabled by Metal–Ligand Supramolecule and Nanostructured Conductive Polymer

What’s Next: The researchers are now investigating the fundamental mechanism for the gelation and self-healing property of this supergel material. They are researching the role of the cubic cage structure of the supermolecule (“molecular unit”) in the processes of gelation and self-healing.

The researchers are also extending this hybrid gel to an aqueous system by modifying chemical structures of the supramolecule. 

Media Coverage:
Electrical circuit made of gel can repair itself,
Scientists develop flexible, self-repairing electrical circuit,
Self-healing hybrid gel system, Nanowerk


Diagram of Hybrid Gel Structure and Properties

The self-healing property of supergel originates from the molecular interactions and assembly effects of supramolecular gel. With designed self-healing and conductive performance, the supergel can be used to construct circuits in flexible and self-repairable electronics.