Researchers from Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) have developed a self-healing, soft adhesive touchpad for touch screens derived from transparent nanocomposite hydrogels.

To improve upon current conductive film used in the manufacture of touchpads — commonly, indium tin oxide, which tends to be fragile — the team developed a stretchy and biocompatible polyzwitterion clay nanocomposite hydrogel that demonstrates 98.8% transmittance and over 1,500% fracture strain.

The pressure sensitive hydrogel film, which is an ionic conductor, can reportedly be adhered to various shaped substrates — glass, wood, cotton fabric, poly(ethylene terephthalate) (PET), acrylonitrile butadiene styrene (ABS), silicone rubber, nylon and poly(methylmethacrylate) (PMMA) — via gentle pressing, making it appropriate for integration into electronic devices and wearable technology.

Further, a surface capacitive touch system was incorporated into each of the touchpad’s corners, forming a unified electrostatic field across the entire touchpad.

Incorporated onto a computer for writing, drawing and gaming applications, the film reportedly demonstrated high-resolution and self-healing properties. In the lab, the direct current in a severed and then reattached hydrogel restored itself in just over 20 seconds. Likewise, the tensile properties and finger location function of reattached hydrogels was also restored.

The research appears in the journal Advanced Materials.