Porous piezoelectric composites and production thereof
Parts made by additive manufacturing are often structural in nature, rather than having functional properties conveyed by a polymer or other component present therein. Printed parts having piezoelectric properties may be formed using compositions comprising a plurality of piezoelectric particles dispersed in at least a portion of a polymer matrix comprising first polymer material and a sacrificial material, the sacrificial material being removable from the polymer matrix to define a plurality of pores in the polymer matrix. The piezoelectric particles may remain substantially non-agglomerated when combined with the polymer matrix. The sacrificial material may comprise a second polymer material. The compositions may define a composite having a form factor such as a composite filament, a composite pellet, a composite powder, or a composite paste. Additive manufacturing processes may comprise forming a printed part by depositing the compositions layer-by-layer and introducing porosity therein.
1 . A composition comprising:
a plurality of piezoelectric particles in at least a portion of a polymer matrix comprising a polymer material and a plurality of interconnected pores defined within the polymer matrix;
wherein the polymer material and the piezoelectric particles collectively define an extrudable material; and
wherein a volume ratio of the plurality of interconnected pores to the polymer material in the polymer matrix ranges from about 10:90 to about 40:60.
2 . The composition of claim 1 , wherein the extrudable material is a composite having a form factor selected from the group consisting of a composite filament, a composite pellet, a composite powder, and a composite paste.
3 . The composition of claim 1 , wherein the extrudable material is a composite filament.
4 . The composition of claim 1 , wherein the polymer material comprises a thermoplastic polymer.
5 . The composition of claim 1 , wherein the piezoelectric particles are covalently bonded to at least a portion of the polymer material, are covalently crosslinkable with at least a portion of the polymer material, and/or interact non-covalently with at least a portion of the polymer material by T-T bonding, hydrogen bonding, electrostatic interactions stronger than van der Waals interactions, or any combination thereof.
6 . The composition of claim 1 , wherein the interconnected pores are devoid of piezoelectric particles.
7 . The composition of claim 1 , wherein the piezoelectric particles are substantially non-agglomerated within the polymer matrix.
8 . The composition of claim 1 , wherein the piezoelectric particles have an average particle size of about 10 microns or less.
9 . A composition comprising:
a plurality of piezoelectric particles in at least a portion of a polymer matrix comprising a polymer material and a plurality of interconnected pores defined within the polymer matrix;
wherein the polymer material and the piezoelectric particles collectively define an extrudable material; and
wherein at least a portion of the interconnected pores is loaded with a backfilling material, the backfilling material being electrically conductive and differing from the polymer material and the piezoelectric particles within the polymer matrix.