Stretchable electronics are dependent on the electrical and mechanical properties of the constituent materials. Commonly this is a blend of an electrically active filler with a stretchable host such as an elastomer. This work will focus on our research understanding how to tune the mechanical properties of host elastomers, focusing on one thermoplastic, styrene-ethylene-butylene-styrene (SEBS), and one thermoset, polydimethylsiloxane (PDMS). While this are very common polymers, much of fundamental knowledge related to the relationship between polymer molecular weight, block or pre-polymer structure, and related viscosity or modulus is still unknown. Additionally, we alter the electrical properties of the polymer by adding fillers such as room temperature liquid metals, iron, graphene, or metal oxides to achieve increased dielectric behavior. Balancing the mechanical properties of the polymer against the electrical properties of the filler, particularly as fillers are known to increase bulk rigidity, is a critical challenge to creating stretchable electronic materials and realizing human-centered, stretchable devices.
