Nanocomposite Dielectric Elastomer Actuator for Micropump Diaphragms- Material Fabrication and Simulation Studies

Electroactive polymers are a class of materials that deform when an electric field is applied. Dielectric elastomers are classified under electroactive polymers that are capable of producing very large deformations and this is due to their elastomeric nature. The fabrication of a dielectric elastomeric actuator based on a polymer nanocomposite with ceramic fillers is reported here. Polydimethylsiloxane (PDMS) was the choice of dielectric elastomer and hexagonal boron nitride (hBN) was used as dielectric fillers, which was added in weight percentages to the polymer. An amorphous carbon-filled polyvinyl acetate composite was used as the compliant electrode. Altering the stiffness of the polymer gives the ability to bring about small actuations, achieved by adding nanofillers to the polymer matrix. The incorporation of hBN into the matrix increased the tensile modulus of the pure PDMS from 0.297 MPa to a maximum of 0.535 MPa with a marginal rise in tensile strength. Scanning electron microscopy and elemental mapping were carried out to understand the morphology and filler distribution in the nanocomposites. From the experiments, the actual voltage (in kV) which was necessary to induce visible actuations in the nanocomposites was determined. Data from the experiments were used in the simulation studies. Finite element analysis was performed on the diaphragm model to predict the behavior of the material and active area displacement of the diaphragm was 1 mm at 8 kV, and deformation of 78 % was achieved. The simulation studies showed that the nanocomposite was perfectly suitable to be used as a pumping mechanism in micropumps.