The Biomedical Polymers Research Group at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), developed ultrastretchable, highly transparent, self-adhesive, and 3D-printable ionically conductive hydrogels for multimode tactical sensing. The study was published in Chemistry of Materials. 

"Ionic skin" is a flexible electronic device that can mimic natural skin to sense external multiple stimuli, such as stress, temperature and humidity, via a biomimetic ion-conductive mechanism. It shows great potential in future healthcare/biomedical applications. As the most promising candidate to fabricate next-generation intelligent “ionic skin”, ionic hydrogels have drawn great attention. However, relatively poor comprehensive performance of conventional ionic hydrogels restricted their future development and practical applications. 

Researchers at NIMTE developed an ionically conductive hydrogel-based electronic technology by introducing charge-rich polyzwitterions into a natural polysaccharide network. 

The synthesized hydrogel showed ultrahigh stretchability (975%), excellent optical transmittance (96.2%), and universal conformal adhesion with different substrates. In addition, it realized dual stress/temperature sensation with high sensitivity. 

By virtue of a facile 3D printing method, a prototype of sensor arrays was fabricated for multimode tactical sensing, which can comprehensively assess bioactivities of the human body in real time. 

The study shed light on various promising applications of tactical sensing in the areas of motion capture, physiological and psychological health assessment, as well as human-machine interface.