Electrospinning process for manufacture of multi-layered structures

Abstract

Devices and methods for high-throughput manufacture of concentrically layered nanoscale and microscale fibers by electrospinning are disclosed. The devices include a hollow tube having a lengthwise slit through which a core material can flow, and can be configured to permit introduction of sheath material at multiple sites of Taylor cone formation formation.

1 . (canceled) 
     
     
         2 . A method of forming an electrospun structure, the method comprising the steps of:
 providing first and second unmixed polymer solutions in an elongated area; and   applying an electric field to at least a portion of the elongated area, thereby forming a plurality of electrospinning jets, wherein the first polymer solution is incorporated in an inner radial portion of each jet and the second polymer solution is incorporated in an outer radial portion arranged about the inner radial portion of each jet.   
     
     
         3 . The method of  claim 2 , wherein the electrospun structure is an elongate fiber having a diameter of less than 20 microns. 
     
     
         4 . The method of  claim 2 , wherein the plurality of electrospinning jets includes at least 10 jets. 
     
     
         5 . The method of  claim 2 , wherein the plurality of electrospinning jets includes at least 100 jets. 
     
     
         6 . The method of  claim 2 , wherein the elongated area is a linear, curvilinear or annular slit. 
     
     
         7 . The method of  claim 6 , wherein the slit is formed within an apex of a wedge-shaped vessel. 
     
     
         8 . The method of  claim 6 , wherein the slit is formed within a tubular vessel. 
     
     
         9 . The method of  claim 2 , wherein the elongated area is defined by at least two parallel plates. 
     
     
         10 . A method of electrospinning a polymer fiber, the fiber having a core including a first material and a sheath including a second material disposed about the core, the method comprising the steps of:
 flowing a first polymer solution comprising the first material within an elongate area;   applying an electric field to at least part of the elongate area, thereby forming a plurality of electrospinning jets originating from a plurality of Taylor cones; and   providing a second polymer solution to at least one of the plurality of Taylor cones, thereby incorporating the first and second polymer solutions into at least one of the electrospinning jets.   
     
     
         11 . The method of  claim 10 , wherein the elongated area is a linear, curvilinear or annular slit. 
     
     
         12 . The method of  claim 11 , wherein the slit is formed within an apex of a wedge-shaped vessel. 
     
     
         13 . The method of  claim 11 , wherein the slit is formed within a tubular vessel. 
     
     
         14 . The method of  claim 11 , wherein the step of providing the second polymer solution to the at least one Taylor cone comprises flowing the second polymer solution around the slit. 
     
     
         15 . The method of  claim 11  wherein the elongated area is defined by at least two parallel plates. 
     
     
         16 . The method of  claim 15 , wherein the step of providing the second polymer solution to the at least one Taylor cone comprises flowing the second polymer solution around the at least two parallel plates. 
     
     
         17 . A method of forming an electrospun structure using an apparatus comprising a first wedge-shaped vessel having a first slit at an apex thereof, and a second wedge-shaped vessel including a second sit at an apex thereof, the first wedge-shaped vessel disposed inside of the second vessel such that the first and second slits are aligned, the method comprising the steps of:
 flowing a first polymer solution comprising the first material through the first wedge-shaped vessel and the first slit;   flowing a second polymer solution comprising the second material through the second wedge-shaped vessel and the second slit; and   applying an electrical field to at least part of at least one of the first and second slits, thereby forming a plurality of electrospinning jets, each jet incorporating the first and second polymer solutions.   
     
     
         18 . The method of  claim 17 , wherein the apparatus includes a collecting area having at least one electrically grounded point thereon, the method further comprising the step of collecting the electrospun structure within the collecting area.