Electrochemically Powered Dissipative Materials

Living organisms can produce materials with dynamic, adaptive and evolving properties, regulating their biological activity in response to changes in their environment. However, synthetic materials that display evolving properties, controlled by electricity through complex regulation processes have not been developed yet. In this thesis, therefore, we want to demonstrate the implementation of electricity for the evolution of stimuli-responsive materials into dissipative materials, which mimic the lifelike functionalities of organisms, enabling a precise control and programmability of the material responses toward more complex operations. We started from the development of metal-coordinated hydrogels, crosslinked by Fe3+ ions, for the fabrication of smart membranes, responsive to ionic strength, and (bio)sensors, employed for the detection of multiple analytes in biological samples. We further implemented out-of-equilibrium redox processes on the metal-coordinated gels to transiently modulate the gel stiffness through controlled reduction from Fe3+ to Fe2+, developing autonomous drug release platforms and soft robotic devices with stiffness-evolving properties. To interface the dissipative behavior of the hydrogel with electronic devices, we developed disulfide-crosslinked hydrogel films integrated on an electrode surface in which electricity was directly employed to precisely modulate the stiffness properties of the network. This platform was employed for the sequential, on-demand release of multiple loads proteins from electrode arrays. The demonstration of electrically driven transient modulation of the stiffness properties of hydrogels represents an important step toward the engineering of dissipative materials with more complex lifelike functionalities for developing future applications, that can harness the temporal, adaptive properties of this new class of materials for the development of next-generation human-machine interfaces.