Inkjet-Printed Iontronics for Transparent, Elastic, and Strain-Insensitive Touch Sensing Matrix

Next-generation soft electronics are expected to be intrinsically stretchable, skin conformable, and fully integrated with diverse receptive modules to facilitate bidirectional human-machine interactions. Receptive touch sensors, in particular, should provide stable touch sensing outputs without being affected by external force-induced strains. Herein, the design and fabrication of an iontronic touch sensing matrix, based on the fringe-field capacitive mechanism, are introduced for robust touch mapping under large deformation. Enabled by our well-formulated ink, ionic gel electrodes are directly inkjet printed onto elastomeric substrate to impart superior transparency and elasticity, and hybridized with a customized electronic circuitry through electrical double layers (EDLs) for the multiplexing and transduction of capacitive signals. Notably, the coplanar interlocking-diamond electrode layout in a stretchable modality is adopted for the first time, which helps to boost touch sensitivity and suppress strain-induced artifacts under static/dynamic deformations. For practical applications, the iontronic matrix demonstrates the capabilities of proximity sensing, multitouch detection, and gesture communication in real time, leading to a robust touch sensing interface that captures high-fidelity signals during complex human-machine interactions.