Hydrogel-based iontronics for actuation, sensing and logic processing

Many critical biological processes, such as sensing, healing, communication, and actuation, rely on electrical signal transduction through ions, unlike current electrically controlled systems that transmit electrons via rigid inorganic components. This mismatch in electrical, mechanical, and chemical properties highlights a gap between biological and man-made systems. To bridge this gap, synthetic materials have been developed by manipulating localized ion concentrations and mobility. While ionic hydrogels have seen significant advancements in ion conductivity, fine control of spatially regulated ion flow remains a challenge. Addressing this, the proposed thesis focuses on designing hydrogel systems with localized ion-controlling capabilities through innovative polymer network chemistry and architecture. Light-responsive hydrogels were engineered to enable on-demand, reversible ion generation for morphing, sensing, and computing, mimicking plant pulvini and neuronal functions. Additionally, a sprayable hydrogel with ultra-fast gelation was developed using architectured, physically crosslinked networks that balance solubility in blocked polyelectrolytes, enabling freeform fabrication with user-defined ion conductivity and types. These advancements not only enable the creation of higher-level circuit components, such as diodes and capacitors but also open new possibilities for enhanced human-computer interactions.