Electrospinning apparatus and nanofibers produced therefrom

Abstract

Provided herein are gas and/or temperature assisted electrospinning apparatus, processes, components and polymer nanofibers.

What is claimed is: 
     
         1 . An electrospinning apparatus for forming nanofibers, comprising:
 a center tube comprising a first supply end and an opposing first nozzle end, the center tube defining a center chamber along a longitudinal axis;   a second tube disposed in surrounding relation to the center tube, the second tube comprising a second supply end and an opposing second nozzle end, one of the center tube or the second tube being a gas supply tube adapted to provide a high velocity gas stream, and the other of the center tube or the second tube being a polymer-feeding tube adapted to provide a polymer liquid, the gas supply tube defining an outer chamber along the longitudinal axis;   a voltage supply proximate to the polymer-feeding tube, the voltage supply adapted to impart an electrical charge to the liquid polymer so as to form a charged liquid polymer jet; and   a collector positioned to capture hardened nanofibers formed from the charged liquid polymer jet.   
     
     
         2 . The electrospinning apparatus of  claim 1 , wherein the center tube is the polymer-feeding tube and the second tube is the gas supply tube. 
     
     
         3 . The electrospinning apparatus of  claim 1 , wherein the center tube is the gas supply tube and the second tube is the polymer-feeding tube. 
     
     
         4 . The electrospinning apparatus of  claim 1 , wherein the first nozzle end and the second nozzle end are in the same axial position along the longitudinal axis. 
     
     
         5 . The electrospinning apparatus of  claim 1 , further comprising a heater configured to heat the high velocity gas stream within the second tube. 
     
     
         6 . The electrospinning apparatus of  claim 1 , further comprising a high temperature nozzle for heating the liquid polymer. 
     
     
         7 . The electrospinning apparatus of  claim 1 , further comprising a cooler for cooling the high velocity gas stream. 
     
     
         8 . An electrospinning apparatus for forming nanofibers, the apparatus comprising:
 a first conduit comprising a first supply end and a first nozzle end, the first conduit being suitable to express a liquid polymer;   at least one gas supply conduit disposed in proximity to the first conduit, the gas supply conduit comprising a second supply end and a second nozzle end; and   a high pressure gas system suitable for expelling high velocity gas from the second nozzle end,   
       wherein
 (a) the first nozzle and the second nozzle are aligned on the same longitudinal axis; 
 (b) the first nozzle comprises a high temperature nozzle; or 
 (c) both (a) and (b). 
 
     
     
         9 . The apparatus of  claim 8 , wherein the first nozzle and the second nozzle are aligned along the same longitudinal axis. 
     
     
         10 . The apparatus of  claim 8 , wherein the first nozzle comprises a high temperature nozzle. 
     
     
         11 . The apparatus of  claim 8 , wherein the high pressure gas system comprises a tapered gas supply conduit such that the second nozzle end is narrower than the second supply end. 
     
     
         12 . The apparatus of  claim 8 , wherein the gas supply conduit comprises a plurality of second nozzle ends. 
     
     
         13 . The apparatus of  claim 8 , wherein the first nozzle end is offset from the second nozzle end by about 0.1 μm to about 20 μm. 
     
     
         14 . The apparatus of  claim 8 , wherein the high velocity gas is provided via the second tube by providing pressurized gas to the second supply end of the second tube. 
     
     
         15 . A fiber preparable according to a process, the process comprising:
 melting a polymer to form a polymer melt;   providing the polymer melt to a center tube, the center tube comprising a first supply end and an opposing first nozzle end, the center tube defining a center chamber along a longitudinal axis, the polymer melt being provided to the first supply end;   providing a high velocity gas via a second tube disposed in surrounding relation to the center tube, the second tube comprising a second supply end and an opposing second nozzle end, the gas supply tube defining an outer chamber along the longitudinal axis, and the high velocity gas having a velocity of greater than 0.01 m/s;   heating the gas with a heater configured to heat the gas within the second tube;   applying a voltage to the center tube, forming a charged liquid polymer jet; and   collecting hardened nanofibers formed from the charged liquid polymer jet.   
     
     
         16 . A nanofiber comprising a polymer, wherein the nanofiber has a diameter of about 50 nm to about 10 μm, and wherein
 (a) at least 10% of the nanofiber is hollow; 
 (b) the polymer is a water soluble polymer; or 
 (c) both. 
 
     
     
         17 . The nanofiber of  claim 16 , wherein the polymer comprises a thermoplastic polymer. 
     
     
         18 . The nanofiber of  claim 16 , wherein the polymer comprises a water-soluble polymer. 
     
     
         19 . The nanofiber of  claim 18 , wherein the water soluble polymer is not soluble in organic solvent, degrades in organic solvent, or both. 
     
     
         20 . The nanofiber of  claim 16 , wherein the polymer is selected from the group consisting of rubber, polycarbonate, polystyrene, poly(methyl methacrylate), poly(lactic acid), polyethylene terephthalate, polybutylene terephthalate, nylon 6, polypropylene, polyethylene, nylon 6,6, and combinations thereof.