Highly Stretchable, Elastic, and Ionic Conductive Hydrogel for Artificial Soft Electronics

Abstract

High conductivity, large mechanical strength, and elongation are important parameters for soft electronic applications. However, it is difficult to find a material with balanced electronic and mechanical performance. Here, a simple method is developed to introduce ion-rich pores into strong hydrogel matrix and fabricate a novel ionic conductive hydrogel with a high level of electronic and mechanical properties. The proposed ionic conductive hydrogel is achieved by physically cross-linking the tough biocompatible polyvinyl alcohol (PVA) gel as the matrix and embedding hydroxypropyl cellulose (HPC) biopolymer fibers inside matrix followed by salt solution soaking. The wrinkle and dense structure induced by salting in PVA matrix provides large stress (1.3 MPa) and strain (975%). The well-distributed porous structure as well as ion migration-facilitated ion-rich environment generated by embedded HPC fibers dramatically enhances ionic conductivity (up to 3.4 S m −1 , at f = 1 MHz). The conductive hybrid hydrogel can work as an artificial nerve in a 3D printed robotic hand, allowing passing of stable and tunable electrical signals and full recovery under robotic hand finger movements. This natural rubber-like ionic conductive hydrogel has a promising application in artificial flexible electronics.

Intelligent perceptual textiles based on ionic-conductive and strong silk fibers

“…As the concentration reaches 2.0 M, the rate of increase in conductivity of the SIH fibers decreases, which is ascribed to that the enhanced interaction between oppositely charged ions in high concentration of ionic liquid solutions hampers ion mobility. The electrical conductivity is up to 0.45 S·m –1 for 2.0M-S, comparable to previously reported conductive hydrogels 25 , 38 , 41 .…”

Flexible and Pressure-Responsive Sensors from Cellulose Fibers Coated with Multiwalled Carbon Nanotubes

“…For each sample with different contents of MWCNTs, two defined parts (compression and decompression) on the stress–strain curves were able to be recognized, which showed the nonlinear mechanical behavior of the pressure sensors. The tendency of the loading–unloading curves confirmed what has been reported in a previous study. , According to Figure , all of the specimens were loaded up to 20 kPa, and the different strain responses during the compression and decompression processes were compared with each other. To be more specific, the strain recovery of the control group was 68.7% (from the strain of 24.6% under the stress of 20 kPa to 7.7% when the load was removed).…”

Strong, tough, ionic conductive, and freezing-tolerant all-natural hydrogel enabled by cellulose-bentonite coordination interactions

“…3a (i–iii), the interaction energy within cellulose is significantly lowered to −0.459 eV when LiCl is introduced in the cellulose-water system. This result predicts the poor mechanical strength of ionic conductive cellulose hydrogels incorporated with inorganic salts, which has been proven in this and previous works 31 . The binding energy between cellulose and BT is calculated to be −5.435 eV, which is ascribed to that cellulose and BT are cross-linked through the formation of Al−O−C bond (Fig.…”