Stretchable spring electrodes for cylindrical dielectric elastomer actuators

Recently, the developments of dielectric elastomer actuators (DEAs) increase rapidly for providing large deformations in micro-scale and bio-compatibility. They are widely used in replacing motors in various areas such as micro-robots and artificial muscles. Most DEAs are composed of stretchable materials sandwiched by inextensible compliant electrodes on both sides and convert input electric energy to mechanical deformation. The main challenge of DEAs is that compliant electrodes do not co-extend with sandwiched material and tend to break during formation resulting in low repeatability and difficulty of manufacturing. In this research, we propose spring electrodes inspired by their mechanical extensibility for designing cylindrical DEA. The proposed structure is composed of a hollow VHB cylinder wrapped by copper springs inside and outside and provide axial deformation under high bias voltages. A prototype was designed, fabricated and examined with laser measurements and a high-voltage source. The research results are expected to provide a new guideline for designing DEAs and benefit to biomedical applications.