Hybrid electrospinner for core-shell fiber fabrication

Abstract

Electrospinning (ES) provides the technical community with a readily available method to produce polymer fibers ranging from nanoscale to microscale. Here, we present a novel “hybrid electrospirming apparatus,” whereby, modifications to a melt electrospinner have allowed fabrication of core-sheath fibers with polymer sheaths and solution-based cores. These modifications include a split polymer melt heating block, coaxial block spinneret equipped with heaters and multiple feed ports for core and sheath material, and a wiring system for heat which requires multiple switches for safety and on-demand heat activation. Successful demonstration of coaxial fiber fabrication is demonstrated using polycaprolactone-polyethylene oxide blend shell and fluorescent gelatin core materials.

1 . A Hybrid ES apparatus comprising:
 a. a heating block, comprised of a polymer melt chamber further comprised of a feed at a bottom end of said polymer melt chamber, and at least one heating block heater cartridge channel isolated from said polymer melt chamber to accept at least one removable heating block heater cartridge;   b. a hybrid spinneret comprised of a concentric spinneret further comprising an outer annular wall and an inner annular wall, where a space is created between said outer annular wall and inner annular wall to accept a melted polymer from said polymer melt chamber feed through a polymer entry port of said hybrid spinneret where said melted polymer enters said space between said outer annular wall and inner annular wall, and   a space is created inside said inner annular wall isolated from said space between said outer annular wall and inner annular wall, which accepts a core solution from a core solution feed located at a first end of said hybrid spinneret;   where said outer annular wall and inner annular wall terminate at a polymer extrusion port located at a second end of said hybrid spinneret; and   whereby said hybrid spinneret is further comprised of at least one removable spinneret heater cartridge channel isolated from said outer annular wall, which accepts at least one removable spinneret heater cartridge.   
     
     
         2 . The Hybrid ES apparatus of  claim 1  where said feed and said polymer entry port are threaded to accommodate a threaded fitting for attachment of said heating block to said hybrid spinneret. 
     
     
         3 . The Hybrid ES apparatus of  claim 1  where a syringe and a syringe pump delivers core solution to the space created by said inner annular wall. 
     
     
         4 . The Hybrid ES apparatus of  claim 1  where said heating block comprises a split block to facilitate cleaning. 
     
     
         5 . The Hybrid ES apparatus of  claim 1  further comprising a temperature controller comprised of a Proportional-Integral-Derivative (PID) controller, which controls the temperature of said heating block and said hybrid spinneret. 
     
     
         6 . The Hybrid ES apparatus of  claim 5  further comprising a main power input controller, and a secondary control switch for said heater cartridges to enable powering of said PID controller without activating said heater cartridges until desired.