Development and modeling of a new ionogel based actuator

Abstract

Ionic electroactive polymer actuators are expected to be one of the most promising driving mechanisms in the future due to their extraordinary features such as their lightweight, flexibility, and low-energy consumption. Traditional ionic electroactive polymer actuators for example, ionic-polymer metal composites have a problem with durability in open air due to the evaporation of water contained in the polymer electrolytes, resulting in a corresponding loss of performance. Electrolysis of the water at relatively low operating voltages may cause deterioration of these materials. Ionic liquids are more thermally and electrochemically stable than water, with unique advantages including negligible volatility, low melting point and high ionic conductivity, therefore they can be used in the application of ionic electroactive polymer actuators. In this work, a new ionic electroactive polymer actuator based on ionogel is developed, which can be operated at low driving voltage with high electrochemical stability. In order to investigate the actuation mechanism of the actuator, a general model consisting of an equivalent electrical circuit, an electromechanical coupling term and a mechanical beam model is built up to characterize its interrelated electrical, mechanical, and chemical properties. This model explains the relationship between input voltage and bending displacement of the actuator. Theoretical and experimental results are demonstrated and documented to validate the conclusion that the model can effectively predict the actuation response of the material. The geometric scalability of the model is also investigated, giving support to the design of the soft mechanism based on ionogel.