Piezoresistive composites via additive manufacturing and composite filaments associated therewith

Abstract

Parts made by additive manufacturing are often structural in nature, rather than having functional properties conveyed by a component present therein. Composite filaments suitable for additive manufacturing may comprise a continuous polymer phase of a first thermoplastic polymer and a second thermoplastic polymer that are immiscible with one another, and electrically conductive particles distributed in the continuous polymer phase, such as microparticles, nanoparticles, or any combination thereof. The first thermoplastic polymer is dissolvable or degradable and the second thermoplastic polymer is insoluble or non-degradable under specified conditions. Removal of the first thermoplastic polymer from a printed part may introduce porosity thereto, thereby inducing or enhancing piezoresistivity within the printed part. An aqueous mixture comprising the electrically conductive particles and the first and second thermoplastic polymers may have water removed therefrom, and the resulting composite residue may be extruded to form the composite filaments.