Hot melt electrospinning

Abstract

Systems, devices, and methods for electro spinning are provided. For example, a system includes a collector including load sensors attached thereto, the collector configured to receive an extruded polymer; and an electro spinning melt head assembly positioned above the collector and configured to extrude the polymer. The electro spinning melt head assembly and/or the collector is configured to move. The melt head assembly includes a syringe assembly and at least one heating element configured to supply heat to the syringe assembly. The syringe assembly includes: a syringe including a passage extending from a proximal end, the passage configured to receive the polymer, and a nozzle configured to allow polymer to pass therethrough.

1 . A system, comprising:
 a collector including load sensors attached thereto, the collector configured to receive an extruded polymer; and   an electrospinning melt head assembly positioned above the collector and configured to extrude the polymer, wherein the electrospinning melt head assembly and/or the collector is configured to move, the melt head assembly including a syringe assembly and at least one heating element configured to supply heat to the syringe assembly, the syringe assembly comprising:
 a syringe including a passage extending from a proximal end, the passage configured to receive the polymer, and 
 a nozzle configured to allow polymer to pass therethrough. 
   
     
     
         2 . The system of  claim 1 , the syringe assembly further comprising:
 a plunger sized and shaped to be slidably received within the passage such that distal motion of the plunger causes extrusion of the polymer;   wherein the system further comprises a plunger drive system configured to supply a mechanical force to actuate the plunger.   
     
     
         3 . The system of  claim 2 , further comprising:
 an imaging system configured to monitor extrusion of the polymer; and   a probe configured to measure a strength of an electric field between the nozzle and the collector.   
     
     
         4 . The system of  claim 3 , further comprising a control and processing system configured to receive signals from the plunger drive system, the imaging system, the load sensors, and the probe, and to control the position of the electrospinning melt head assembly, the force applied to the plunger, a voltage of the collector, and a rate of extrusion of the polymer. 
     
     
         5 . The system of  claim 4 , wherein the rate of extrusion is controlled to follow a rectified sinusoidal profile. 
     
     
         6 . The system of  claim 4 , wherein the rate of extrusion is between 0.1 gram/hour and 10 gram/hour. 
     
     
         7 . The system of  claim 6 , wherein the rate of extrusion is 0.1 gram/hour, 0.2 gram/hour, 0.3 gram/hour, 0.4 gram/hour, 0.5 gram/hour, 0.6 gram/hour, 0.7 gram/hour, 0.8 gram/hour, 0.9 gram/hour, 1.0 gram/hour, 2.0 gram/hour, 3.0 gram/hour, 4.0 gram/hour, 5.0 gram/hour, 6.0 gram/hour, 7.0 gram/hour, 8.0 gram/hour, 9.0 gram/hour, or 10.0 gram/hour. 
     
     
         8 . The system of  claim 4 , wherein the voltage of the collector is between 0 and 20 kV, 1 kV, 2 kV, 5 kV, 10 kV, 15 kV, 20 kV, 25 kV, 30 kV, or 40 kV. 
     
     
         9 . The system of  claim 4 , further comprising a voltage source providing a maximum current to the collector of 0.01 mA, 0.1 mA, 0.18 mA, 0.2 mA, 0.3 mA, 0.6 mA, 1.0 mA, 10 mA, or 100 mA. 
     
     
         10 . The system of  claim 1 , further comprising:
 a drive system including a pump configured to supply a pressure inside the syringe via a gas.   
     
     
         11 . The system of  claim 1 , further including a support assembly that retains the electrospinning melt head assembly or the collector. 
     
     
         12 . An electrospinning melt head assembly, comprising:
 a syringe assembly including,
 a nozzle, 
 a plunger including at least one sealing element disposed on an outer surface thereof, 
 a first passage extending from a first opening in a proximal end of the syringe assembly, the passage being sized and shaped to slidably receive the plunger such that the at least one sealing element on the plunger forms a seal with a wall that defines the first passage, 
 a second opening in a distal end, the second opening being fluidly coupled to the first passage, the second opening being sized and shaped to releasably receive the a portion of the nozzle therein; 
   at least one heating element configured to supply heat to the syringe assembly.   
     
     
         13 . The assembly of  claim 12 , further comprising a heater assembly that retains the at least one heating element, the heater assembly having a second passage extending from a proximal end thereof, the second passage sized and shaped to receive the at least a portion syringe assembly. 
     
     
         14 . The assembly of  claim 13 , wherein the at least one heating element encircles the second passage. 
     
     
         15 . The assembly of  claim 13 , wherein the heating element is positioned within a lower half of the heater assembly. 
     
     
         16 . The assembly of  claim 13 , further comprising an insulation sleeve, the insulation sleeve having a third passage configured to receive the syringe assembly and the at least one heating element. 
     
     
         17 . A method comprising:
 applying power to a heating element to generate heat to transfer to a polymer and melt the polymer within a syringe;   measuring a temperature associated with the polymer;   applying a voltage to a collector to generate an electric field across a gap between the collector and a nozzle that is releasably coupled to the syringe;   moving the nozzle and/or the collector to pass the nozzle over a portion of the collector at least one time; and   applying force to a proximal end of a plunger that is slidably disposed within the syringe to force the plunger toward the nozzle, thereby forcing a portion of the polymer out of the nozzle and into the electric field such that it creates a polymer stream extending from the nozzle, wherein the polymer stream cools and forms fibers during travel from the nozzle to the collector.   
     
     
         18 . The method of  claim 17 , further comprising adjusting a size of the gap with every pass of the nozzle over a given point on the collector. 
     
     
         19 . The method of  claim 17 , further comprising moving the nozzle and/or collector based on an excursion profile to create small bends in the polymer stream. 
     
     
         20 . The method of claim  0 , wherein the excursion profile includes a rectified sinusoidal profile. 
     
     
         21 . The method of  claim 17 , further comprising using load sensors to determine a rate of polymer extrusion from the nozzle. 
     
     
         22 . The method of  claim 17 , further comprising using an imaging system in conjunction with machine vision software to determine a rate of polymer extrusion from the nozzle. 
     
     
         23 . The method of  claim 17 , wherein air pressure creates the force at the proximal end of the plunger. 
     
     
         24 . The method of claim  0 , further comprising reducing the air pressure sufficiently to draw the plunger away from the nozzle to stop, or reduce, flow of polymer from the nozzle. 
     
     
         25 . The method of  claim 17 , further comprising measuring a strength of the electric field. 
     
     
         26 . The method of  claim 25 , further comprising adjusting the voltage of the collector based on the measured strength of the electric field. 
     
     
         27 . The method of  claim 25 , further comprising adjusting a size of the gap between the nozzle and the collector based on the measure strength of the electric field. 
     
     
         28 . A system comprising:
 a collector including load sensors attached thereto, the collector configured to receive an extruded polymer;   an electrospinning melt head assembly positioned above the collector and configured to extrude the polymer, wherein the electrospinning melt head assembly and/or the collector is configured to move in at least one of X, Y, and Z directions, the melt head assembly including a syringe assembly and at least one heating element configured to supply heat to the syringe assembly, the syringe assembly comprising:   a syringe including a passage extending from a proximal end, the passage being configured to receive the polymer,   a nozzle configured to allow polymer to pass therethrough;   a drive system configured to supply a pressure inside the syringe;   an imaging system configured to monitor extrusion of the polymer; and   a probe configured to measure a strength of an electric field between the nozzle and the collector.   
     
     
         29 . The system of  claim 28 , further comprising a control and processing system configured to receive signals from the drive system, the imaging system, the load sensors, and the probe, and to control the position of the electrospinning melt head assembly, the pressure supplied to the syringe, a voltage of the collector, and a rate of extrusion of the polymer. 
     
     
         30 . The system of  claim 28 , further including a support assembly that retains the electrospinning melt head assembly or the collector. 
     
     
         31 . An electrospinning melt head assembly, comprising:
 a syringe assembly including
 a nozzle, 
 a first passage extending from a first opening in a proximal end of the syringe assembly, 
 a second opening in a distal end, the second opening being fluidly coupled to the first passage, the second opening being sized and shaped to releasably receive the a portion of the nozzle therein; 
   at least one heating element configured to supply heat to the syringe assembly.   
     
     
         32 . The assembly of  claim 31 , further comprising a heater assembly that retains the at least one heating element, the heater assembly including a second passage extending from a proximal end thereof, the second passage sized and shaped to receive the at least a portion syringe assembly. 
     
     
         33 . The assembly of  claim 32 , wherein the at least one heating element encircles the second passage. 
     
     
         34 . The assembly of  claim 32 , wherein the heating element is positioned within a lower half of the heater assembly. 
     
     
         35 . The assembly of  claim 32 , further comprising an insulation sleeve, the insulation sleeve including a third passage configured to receive the syringe assembly and the at least one heating element. 
     
     
         36 . (canceled)