Electrochemical devices based on conducting surfaces modified with smart hydrogels: Outlook and perspective

The unique properties of smart hydrogels combined with conducting surfaces opened new possibilities in the construction of novel electrochemical devices. Electrodes modified with thin gel layers demonstrate the properties that are usually unachievable for bare electrodes. Usually a thin gel layer provides a highly permeable matrix for analytes, and can also serve as an immobiliz- ing/impermeable matrix for larger molecules. Hydrogel barriers/layers are able to protect the electrode surface against the unwanted influence of the environ- ment and to isolate the environment from the usually metallic, stiff, and hard electrode surfaces. A layer of hydrogel attached to the electrode surface can also serve as solid electrolyte, buffer and a reservoir for electroactive probes. In addi-tion, the ability of smart gel materials to undergo a reversible volume phase tran- sition related to significant changes in their volume and shape is very interesting from the point of view of the construction of switchable electrochemical systems. Such properties are strongly desired for the construction of various electrochem- ical devices. This review is focused on recent progress in the above field