Self-maintained colorimetric acid/base sensor using polypyrrole actuator

A novel approach to autonomous chemical sensor regeneration is explored in this paper. It involves the movement of a sensor surface into measurement or regeneration zones using low powered conducting polymer actuators. The system demonstrated the feasibility of repeatedly cycling through a measurement–regeneration regime, which in principle allows remotely deployed chemical sensors to perform simple self-diagnostics. The sensor-actuator device is shown to repeatedly switch through 120 measurement–regeneration cycles. Detection of pH-dependent colour changes is demonstrated using LED-based colorimetry and remotely deployed video cameras.