Hofmeister Effect and Electrostatic Interaction Enhanced Ionic Conductive Organohydrogels for Electronic Applications

Abstract The emerging cryoprotectant replacement method endows hydrogels with nondrying and antifreezing properties, but the low conductivity still limits wider electronic applications. In this work, the Hofmeister effect and electrostatic interaction are introduced to improve the conductivity of organohydrogels and their enhancement mechanism are studied in depth. The Hofmeister effect mainly influences the physical properties, such as the pore structure and mechanical strength, which subsequently impacts ion transfer during the solvent replacement process. The lithium and sodium bonds formed by the electrostatic interaction play a more important role in the conductivity of organohydrogels and an overall picture is presented based on the synergistic enhancement of the Hofmeister effect and electrostatic interaction to achieve highly ionic conductive organohydrogels. The champion organohydrogels are applied as soft ionic conductors and antireflective layers in triboelectric, photovoltaic, and thermoelectric applications. The proposed mechanism advances the understanding of the contribution of ions to organohydrogels for wearable electronics.