Active Compression Bandage Made of Electroactive Elastomers

Active compression bandages made of electro-mechanically active elastomers have recently been proposed to counteract dynamically, rather than statically, limb swelling due to various pathologies or conditions. To apply and modulate the compression pressure they exploit the ability of electroactive elastomer layer/s of changing size in response to a high voltage. For safety reasons such devices must be properly insulated from the user limb. In this work we present an electroactive bandage made of two pre-stretched layers of an electroactive acrylic elastomer sandwiched between two insulating layers of a passive silicone elastomer. Moreover, uniaxial stiffening elements where introduced to maximise actuation along the radial direction. Prototypes of the bandage were tested with a pressurized air chamber, which mimicked the compliance of a human limb. Both experimental investigations and a finite electro-elasticity analytical model showed that the passive layers play a key role for an effective transmission of actuation from the active layers to the load. The prototypes were able to actively vary the applied pressure up to 10%. The model showed that by increasing the number of electroactive layers the pressure variation could be further increased, although with a saturation trend, providing useful indication for future designs of such bandages.