Mechanical Properties of Stretchable Multifunctional Ecoflex Composites for E-Skin Applications

Abstract Stretchable silicone elastomers are widely used in various applications such as robotics and wearable technologies due to their mechanical tunability, widespread availability, low cost, and ease of manufacturing. However, elastomers typically have no functional properties, and are often just used for their unique mechanical properties. Recently composite materials using an elastomer backbone have been developed to add functionality such as electrical conductivity, piezoelectric, and magnetic properties. However, research on the effects of mechanical properties due to the addition of these nanoparticles is limited, especially at the micro scale. This study investigates the feasibility of fabricating highly stretchable Ecoflex 00-30 composites containing various nanoparticles and the mechanical properties of these composites. Various nanoparticles were investigated with varying concentrations, and we investigated macro and micro sized samples. Nanoparticles investigated include lead zirconate titanate, neodymium iron boron, Terfenol-D and mixtures of these with varying concentrations up to 80 wt%. The 80% NdFeB composite demonstrated a remanence value of 0.75 T. The piezoelectric properties of PZT/Ecoflex were 1.7 pC/N (d33), and the Terfenol-D composite demonstrated a Villari effect. Most particularly, mechanical behavior of the samples has been comprehensively analyzed based on the tensile tests of different sized specimens. With increasing particle concentration, a promising elevation in the elastic modulus along with a high ductility was obtained.