Gelatin-based film that can self-repair smartphones

“This film can be further implemented to wearable devices in the near future, since the wearable device will be continuously flexed (cracked) during application”Yu-Chi Chang

A self-healing gelatin-based film that can repair itself numerous times while maintaining the electronic signals required to access data in a device has been demonstrated by a group from the National Cheng Kung University in Taiwan. The film offers useful properties for overcoming fragility problems – such as cracks in the casing, or fractures develop in the material that stores data – in touchscreen and flexible display devices, and could also find uses in advanced robotics and assisted health technologies.

Gelatin has already been employed in new electronic devices due it its translucency, flexibility, water solubility and biodegradability. It is also easily available and safe, and can be easily stored in an ambient atmosphere for long periods without deterioration. However, damaged gelatin films tend not to restore quickly, while other self-repairing films usually work only once, and can contain harmful agents. However, as reported in ACS Applied Polymer Materials [Chang et al. ACS Appl. Polym. Mater. (2020) DOI: 10.1021/acsapm.0c01119], this research investigated if it was possible to develop a repeatedly self-healing gelatin-based film that could mend cracks quickly while preserving electrical functionality.

The team had previously applied gelatin to resistive memory, showing excellent stability, and developed fully transparent resistive memory, highly uniform resistive memory elements and full biological properties with decomposed electronic components. While gelatin shows promise for making flexible resistive memory components, their previous work had shown that continuous deflection made the gelatin irregular and caused cracks in the film, resulting in rapid loss in the performance for resistive memory devices.

Here, glucose was combined with gelatin to produce a flexible film that was then placed in a conductive material to simulate an electronic device. When this device was bent, breaks in the gelatin-glucose film disappeared within three hours at room temperature, and also within 10 minutes when the device was heated to 60⁰C. The glucose-based gelatin was also able to send out an electrical signal after many rounds of damage and repair, with the film's electrical performance also surprisingly being improved.

When supplemented by temperature from the human body, the film could possibly be used in wearable components. As group leader Yu-Chi Chang told Materials Today, “This film can be further implemented to wearable devices in the near future, since the wearable device will be continuously flexed (cracked) during application”. 

With the method for producing this film being relatively straightforward, the researchers expect many applications in electronic components and biomedicine. They are continuing apply the self-healing film to different electronic components, such as sensing components, and to complete self-healing circuits without the need for a vacuum process.