BS in Materials Engineering
Materials Engineering Department
Richard N. Savage
An artificial muscle design was created founded on the principles of a dielectric electroactive polymer (DEAP), which is fundamentally similar to a capacitor. A polydimethyl siloxane (PDMS)-based elastomer, Sylgard 184 from Dow Corning, was chosen for the design and spun coat onto polystyrene (PS) Petri dishes at varying speeds to create a thin film, using speeds of 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, and 6000 rpm. The film thicknesses were measured optically through use of a microscope with coupled computer imaging software to generate a characteristic curve of film thickness to spin speed, achieving a minimum film thickness of 15.9 microns at a spin speed of 6000 rpm. A second elastomer, 3-6121 Low Temperature Elastomer from Dow Corning, was attained and compounded at varying volume ratios with the primary Sylgard 184 in effort to obtain a polymer compound with a decreased compressive modulus, effectively reducing the required actuation voltage of the design. Varying polymer compounds were tested in compression and the compound of 80 vol% primary elastomer and 20 vol% secondary elastomer was found to have a drastically reduced modulus of compression. Thin films of pure primary elastomer and the reduced-modulus polymer compound were created for electrostatic actuation testing, measured via interferometry. Dielectric breakdown was observed during electrostatic testing before significant actuation was achieved. Mechanical actuation testing using .5 kg, 1 kg, 1.5 kg, and 2 kg masses was adopted to prove the concept. Mechanical testing proved successful, achieving a maximum actuation of 20% strain and 35% strain for the pure primary elastomer and the reduced-modulus polymer compound, respectively.