Capacitive/Resistive Strain Sensors Based on Organogel/Hydrogel Hybrids via a Low-Swelling Solvent Replacement Strategy

As potential flexible sensors to mimic skin functions or achieve human–computer interactions, organogel/hydrogel hybrids, prepared mostly through "adhesion strategies" and "interfacial polymerization strategies", have gained increasing attention in recent years. Herein, the organogel/hydrogel hybrids with different structures and functions were prepared through a low-swelling solvent replacement strategy. Organogel/hydrogel hybrids were prepared by in situ solvent replacement with aqueous NaCl solution (10 wt %) on native organogels, which were fabricated by photoinitiated copolymerization of methacrylic acid (MAAc) and N-(pyridin-2-yl)acrylamide (NPAM) in glycerol. Capacitive or resistive modal sensors based on organogel/hydrogel hybrids can be obtained easily. In particular, because the patterns were completely dependent on the mold containing the displacing solvent, flexible electronic sensors based on organogel/hydrogel hybrids with complex topological structures and functions could be designed and prepared conveniently. Since the interface between the hydrogel and the organogel also formed in situ and was very strong, the organogel/hydrogel hybrids exhibit excellent puncture-resistant performance. Our experimental results indicated that organogel/hydrogel hybrids with complex patterns and topologies could be prepared through a low-swelling solvent replacement strategy. The design and practical application of flexible electronic sensors based on organogel/hydrogel hybrids will be enlarged and advanced substantially.