In-process ultrasonic polling of 3d printed crystalline/semicrystalline electroactive polymers

Abstract

Methods and systems for producing a structure having selectable piezoelectric properties via additive manufacturing. Such methods can include coupling an ultrasound generating device to a print head of the additive manufacturing apparatus; transmitting acoustic energy from the ultrasound generating device to the print head to vibrate the print head in an oscillatory manner; extruding a feed material from the print head; moving the print head in at least one dimension relative to a substrate on which the structure is being manufactured; and dispensing layers sequentially on top of each other to form the structure. Such systems can include an additive manufacturing apparatus comprising a print head movable in at least one dimension relative to a base configured to support the structure being produced; and an ultrasound generating device that is connected to the print head.

1 - 13 . (canceled) 
     
     
         14 . A system for producing a structure having selectable piezoelectric properties via additive manufacturing, the system comprising:
 an additive manufacturing apparatus comprising a print head movable in at least one dimension relative to a base configured to support the structure being produced; and   an ultrasound generating device that is connected to the print head, the ultrasound generating device being configured to generate acoustic energy that is transferred to a polymer melt contained within the print head, wherein the acoustic energy causes an oscillatory vibration of the print head;   wherein the print head is configured to extrude the polymer melt over a substrate and/or over a previously deposited layer of the structure.   
     
     
         15 . The system of  claim 14 , wherein the structure is formed by sequentially dispensing layers of the polymer melt extruded from the print head on top of each other. 
     
     
         16 . The method of  claim 14 , comprising a heater block within a hot-end section of the print head that heats a polymeric feeder material to form the polymer melt. 
     
     
         17 . The system of  claim 14 , wherein the acoustic energy causes an alignment and/or relaxation of polymeric chains within the polymer melt. 
     
     
         18 . The system of  claim 17 , wherein the alignment and/or relaxation of the polymeric chains causes the structure to have piezoelectric properties. 
     
     
         19 . The system of  claim 18 , wherein the polymeric chains are fixed within the polymer melt after the polymer melt is extruded from the print head, such that the alignment and/or relaxation of the polymeric chains is maintained by a hardening of the polymer melt when the polymer melt is cooled. 
     
     
         20 . The system of  claim 14 , wherein the ultrasound generating device is configured to selectively apply acoustic energy to the print head by changing the ultrasound generating device between an on state and an off state. 
     
     
         21 . The system of  claim 20 , wherein:
 portions of the structure are dispensed while the ultrasound generating device is in the on state so that the portions of the structure have piezoelectric properties; and   other portions of the structure are dispensed while the ultrasound generating device is in the off state so that the other portions of the structure do not have piezoelectric properties and act as insulators.   
     
     
         22 . The system of  claim 14 , wherein the polymer melt is created by melting a source of a polymer comprising polyvinylidenefluoride (PVDF) and/or a co-polymer thereof, including poly[vinylidenefluoride-co-trifluoroethylene] (P(VDF-TrFE)). 
     
     
         23 . The system of  claim 14 , wherein each dispensed layer has a shape corresponding to a cross-section of the structure being produced. 
     
     
         24 . The system of  claim 14 , wherein the oscillatory vibration of the print head is caused by a movement of the print head in a direction orthogonal to a longitudinal axis of the print head and/or in a direction parallel to the longitudinal axis of the print head. 
     
     
         25 . The system of  claim 24 , wherein the polymer melt is extruded from a nozzle of the print head, the nozzle being coaxial to the longitudinal axis of the print head. 
     
     
         26 . The system of  claim 14 , wherein the acoustic energy has a frequency that is substantially similar to a natural frequency of the additive manufacturing apparatus.