Electrically conductive, self-healing material

A group of scientists from the University of Texas at Austin, USA, under the leadership of Yu Guihua, created a flexible electric circuit based on a special gel, which, if cut into two, is completely self-healing and resumes its original electrical conductivity.

The new gel has a combination of properties that were not previously met together, it is flexibility, high electrical conductivity, and the ability to self-repair at room temperature. This solution opens up a wide range of possible applications: flexible electronics, robotics, electric batteries, and even soft artificial leather and biomimetic prostheses.

The property of the new gel is provided by two gel-like constituents of its substance: a supramolecular gel (or “supergel”), and a matrix of a conductive polymer hydrogel into which the supramolecular gel is introduced. So the physical and chemical characteristics of each component are combined.

Introduced supergel gives the ability to self-healing, thanks to its supramolecular chemical structure, the peculiarity of which is that not individual molecules, but large molecular compounds are the constituent elements of the structure.

These large substructures are held together by forces much smaller than individual molecules, so their interactions, such as separation, are easily reversible. It turns out "dynamic glue", capable of reuniting itself during separation.

Meanwhile, the conductive hydrogel, due to its three-dimensional structure, provides conductivity. The three-dimensional structure facilitates the transport of electrons. In addition, the hydrogel, like the spine, enhances the strength and elasticity of the composite gel. When a supergel is introduced into the hydrogel matrix, it flows around the hydrogel in such a way that it forms a second network, further enhancing the integrity of the hybrid gel.

Scientists conducted their experiments on checking electrical properties on thin films of a hybrid gel deposited on flexible plastic substrates. Studies have shown that the conductivity of the new gel is one of the highest among conductive gels, and remains so due to the ability of the gel to self-repair even after repeated bending and stretching.

Scientists have shown that if an electric circuit made of a hybrid gel is cut, then in a minute it will recover itself, and the electrical conductivity will be the same as before the cut. This happens even after repeated cutting in the same place.

According to researchers, the hybrid gel they invented will find many applications, up to implantable biosensors, where self-healing electrodes are simply necessary to ensure device durability. The gel can easily be used to strengthen the electrodes. lithium ion batteries high capacity.

The developers of the new conductive gel are confident that their approach to combining supramolecular chemistry with polymer nanoscience creates a strategy for developing new self-healing materials. They plan to explore the fundamental mechanisms of self-healing in order to better understand the key factors regarding ions of various metals, the geometry of molecules, the interaction of supramolecules with various solvents, and how this affects the characteristics of self-healing. This will contribute to the improvement of newly developed materials.

The head of the group, Yu.Guihua, noted that special efforts will be devoted to developing large-scale strategies for producing self-healing conductive gels with better properties, such as mechanical strength and elasticity, so that the use of conductive self-healing gels becomes potentially possible in many different technological areas, including electronics, energy, security environment and health.