A novel method of fabricating laminated silicone stack actuators, with pre-strained dielectric layers

In recent studies, stack based Dielectric Elastomer Actuators (DEAs) have been successfully used in haptic feedback and sensing applications. However, limitations in the fabrication method, and materials used to construct stack actuators constrain their force and displacement output per unit volume. This paper focuses on a fabrication process enabling a stacked elastomer actuator to withstand the high tensile forces needed for high power applications, such as mimetics for mammalian muscle contraction (i.e prostheses), whilst requiring low voltage for thickness-mode contractile actuation. Spun elastomer layers are bonded together in a pre-strained state using a conductive adhesive filler, forming a Laminated Inter-Penetrating Network (L-IPN) with repeatable and uniform electrode thickness. The resulting structure utilises the stored strain energy of the dielectric elastomer to compress the cured electrode composite material. The method is used to fabricate an L-IPN example, which demonstrated that the bonded L-IPN has high tensile strength normal to the lamination. Additionally, the uniformity and retained dielectric layer pre-strain of the L-IPN are confirmed. The described method is envisaged to be used in a semi-automated assembly of large-scale multi-layer stacks of pre-strained dielectric layers possessing a tensile strength in the range generated by mammalian muscle.