Organic Semiconductor Nanotubes for Electrochemical Devices

Electrochemical devices that transform electrical energy to mechanical energy through an electrochemical process have numerous applications ranging from soft robotics and micropumps to autofocus microlenses and bioelectronics. To date, achievement of large deformation strains and fast response times remains a challenge for electrochemical actuator devices operating in liquid wherein drag forces restrict the actuator motion and electrode materials/structures limit the ion transportation and accumulation. We report results for electrochemical actuators, electrochemical mass transfers, and electrochemical dynamics made from organic semiconductors (OSNTs). Our OSNTs electrochemical device exhibits high actuation performance with fast ion transport and accumulation and tunable dynamics in liquid and gel-polymer electrolytes. This device demonstrates an excellent performance, including low power consumption/strain, a large deformation, fast response, and excellent actuation stability. This outstanding performance stems from enormous effective surface area of nanotubular structure that facilitates ion transport and accumulation resulting in high electroactivity and durability. We utilize experimental studies of motion and mass transport along with the theoretical analysis for a variable-mass system to establish the dynamics of the electrochemical device and to introduce a modified form of Euler-Bernoulli's deflection equation for the OSNTs. Ultimately, we demonstrate a state-of-the-art miniaturized device composed of multiple microactuators for potential biomedical application. This work provides new opportunities for next generation electrochemical devices that can be utilized in artificial muscles and biomedical devices.