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Electrochemical devices that transform electrical energy to mechanical energy through an electrochemical process have numerous applications ranging from robotics and micropumps to microlenses and bioelectronics. To date, achievement of large deformation strains and fast responses remains challenging for electrochemical actuators wherein drag forces restrict the device motion and electrode materials/structures limit the ion transportation. Results for electrochemical actuators, electrochemical mass transfers, and electrochemical dynamics made from organic semiconductors (OSNTs) are reported. The OSNTs device exhibits high‐performance with fast ion transport and accumulation in liquid and gel‐polymer electrolytes. This device demonstrates an impressive performance, including low power consumption/strain, a large deformation, fast response, and excellent actuation stability. This outstanding performance stems from the enormous effective surface area of nanotubes that facilitates ion transport and accumulation resulting in high electroactivity and durability. Experimental studies of motion and mass transport are utilized along with the theoretical analysis for a variable–mass system to establish the dynamics of the device and to introduce a modified form of Euler‐Bernoulli's equation for the OSNTs. Ultimately, a state‐of‐the‐art miniaturized device composed of multiple microactuators for potential biomedical applications is demonstrated. This work provides new opportunities for next‐generation actuators that can be utilized in artificial muscles and biomedical devices.

Conservative and non‐conservative phase‐field models are considered for the numerical simulation of lateral phase separation and coarsening in biological membranes. An unfitted finite element method is proposed to allow for a flexible treatment of complex shapes in the absence of an explicit surface parametrization. For a set of biologically relevant shapes and parameter values, the paper compares the dynamic coarsening produced by conservative and non‐conservative numerical models, its dependence on certain geometric characteristics and convergence to the final equilibrium.