Carbon nanofiber hybrid actuators: Part I - Liquid electrolyte-based

This two-part article describes a carbon nanofiber-polymethylmethacrylate (CNF-PMMA) composite material that has electrochemical actuation properties. Part I of the study considers use of a liquid electrolyte while Part II considers a solid electrolyte. Concerning Part I, a combination of solvent casting and melt mixing were used to disperse CNF in PMMA, and thin films of the material were cast. A liquid-based electrochemical actuator was formed by placing the CNF composite film in an electrolyte solution. Electrochemical impedance spectroscopy was carried out to characterize the electrochemical properties of the PMMA-CNF actuator. The actuator was tested at voltages up to 15 V and the relationship between displacement and applied voltage was determined. Compared to previous single-wall carbon nanotube buckypaper actuators, the CNF-PMMA composite actuator is stronger and is two orders of magnitude lower in cost, but needs higher voltage to actuate. Because of the low cost of the CNF hybrid material, and the possibility for using stronger host materials, new smart structural materials that enable large components and structures to actuate may become feasible.