Electrospinning

Abstract

Among other things, fibers are electrospun using an electrospinning structure comprising a base and at least one emitting element on the base, a first electrode arranged at a distance from the free end of the at least one emitting element, and optionally a collection element between the at least one emitting element and the first electrode, the collection element being configured to collect the fibers. The at least one emitting element has a projecting free end. At least a portion of the base, the at least one emitting element, or both include a porous material. The first electrode is configured to cause fibers to be produced from the free end of the at least one emitting element.

What is claimed is: 
     
         1 . An apparatus for producing fibers, comprising:
 an electrospinning structure comprising a base and at least one emitting element on the base, the at least one emitting element having a projecting free end, at least a portion of the base or the at least one emitting element or both comprising a porous material;   a first electrode arranged at a distance from the free end of the at least one emitting element and configured to cause fibers to be produced from the free end of the at least one emitting element; and   optionally, a collection element between the at least one emitting element and the first electrode, the collection element being configured to collect the fibers.   
     
     
         2 . The apparatus of  claim 1 , further comprising a second electrode, wherein at least a portion of the electrospinning structure is between the first and second electrodes. 
     
     
         3 . The apparatus of  claim 1 , wherein the electrospinning structure comprises a second electrode. 
     
     
         4 . The apparatus of  claim 1 , wherein the porous material comprises a polymer, a metal, a ceramic, or a combination of any two of more of them. 
     
     
         5 . The apparatus of  claim 1 , wherein the porous material comprises a polyurethane, a polytetrafluoroethylene, a polyethylene, a polypropylene, a polyvinylidene fluoride, or an ethyl vinyl acetate, or a combination of any two or more of them. 
     
     
         6 . The apparatus of  claim 1 , wherein the porous material has an average pore size from about 0.1 microns to about 100 microns. 
     
     
         7 . The apparatus of  claim 1 , wherein the porous material is substantially hydrophilic. 
     
     
         8 . The apparatus of  claim 1 , wherein at least a portion of the electrospinning structure has a porosity that allows a liquid to pass along at least a portion of a path that extends from a source of the liquid to the free end of the emitting element. 
     
     
         9 . The apparatus of  claim 1 , wherein the electrospinning structure comprises a vessel for containing a liquid from which the fibers are to be formed. 
     
     
         10 . The apparatus of  claim 9 , wherein a second electrode is disposed in the vessel. 
     
     
         11 . The apparatus of  claim 1 , wherein the apparatus comprises a vessel for containing a liquid from which the fibers are to be formed, a second electrode and at least a portion of the electrospinning structure being disposed in the vessel. 
     
     
         12 . The apparatus of  claim 1 , wherein the first electrode is configured to collect the fibers. 
     
     
         13 . The apparatus of  claim 12 , wherein the first electrode comprises a plate. 
     
     
         14 . The apparatus of  claim 13 , wherein the plate is continuous at a location that corresponds to the location of the free end of the at least one emitting element. 
     
     
         15 . The apparatus of  claim 11 , wherein the first electrode comprises a screen. 
     
     
         16 . The apparatus of  claim 1 , wherein the apparatus comprises the collection element. 
     
     
         17 . The apparatus of  claim 1 , wherein the apparatus comprises a power source electrically connected to the first electrode and a second electrode. 
     
     
         18 . The apparatus of  claim 17 , wherein the power source is configured to generate a voltage of from about 100 V to about 100,000 V. 
     
     
         19 . The apparatus of  claim 1 , wherein the at least one emitting element has an opening and the opening has a diameter of from about 10 μm to about 250 μm. 
     
     
         20 . A method of forming fibers, comprising:
 applying a voltage across at least a portion of an electrospinning structure comprising a base and at least one emitting element on the base such that a liquid passes along at least a part of a path from a source of the liquid to the at least one emitting element and to be emitted from the at least one emitting element to form fibers.   
     
     
         21 . A method, comprising:
 mixing at least one sol gel precursor, at least one magnetic material, and at least one solvent to form a mixture;   applying a magnetic field to the mixture to form protrusions on a surface of the mixture; and   removing the solvent from the mixture to form a porous electrospinning structure.   
     
     
         22 . The method of  claim 21 , wherein the at least one magnetic material comprises magnetic nanoparticles. 
     
     
         23 . The method of  claim 22 , wherein the magnetic nanoparticles comprise iron-containing nanoparticles. 
     
     
         24 . The method of  claim 22 , wherein the magnetic nanoparticles are coated with a surfactant. 
     
     
         25 . The method of  claim 21 , wherein the at least one sol gel precursor comprises a metal alkoxide, a metal chloride, or a metal nitrate, or a combination of two or more of them. 
     
     
         26 . The method of  claim 25 , wherein the least one sol gel precursor comprises tetramethyl orthosilicate, tetraethyl orthosilicate, or aluminum chloride, or a combination of two or more of them. 
     
     
         27 . The method of  claim 25 , further comprising adding a catalyst after forming protrusions on a surface of the mixture. 
     
     
         28 . The method of  claim 27 , wherein the catalyst is an acid or a base. 
     
     
         29 . An apparatus, comprising
 a set of elongated elements, each of the elements projecting from a base to a free end, each of the elements comprising a material that is porous to a liquid from which fibers are to be formed by electrospinning from the free end of the element, and   a vessel to contain a volume of the liquid,   wherein the bases of the elements are configured so that at least portions of the bases are in contact with the liquid.   
     
     
         30 . An apparatus, comprising
 a set of elongated elements, each of the elements projecting from a base to a free end, each of the elements comprising a material that is porous to a liquid from which fibers are to be formed by electrospinning from the free end of the element, and   an electrode plate arranged at a distance from the free ends of the elements for electrospinning from the free ends of the elements to the electrode plate, the electrode plate being continuous at locations that correspond to locations of the free ends of the elongated elements.   
     
     
         31 . An apparatus, comprising
 a set of elongated elements, each of the elements projecting from a base to a free end, each of the elements comprising a material that is porous to a liquid from which fibers are to be formed by electrospinning from the free end of the element, surfaces of the porous material that are to be in contact with the liquid being hydrophilic.   
     
     
         32 . An apparatus, comprising
 a set of elongated elements, each of the elements projecting from a base to a free end, each of the elements comprising a material that is porous to a liquid from which fibers are to be formed by electrospinning from the free end of the element, and   a vessel to contain a volume of the liquid, the vessel being unsealed.   
     
     
         33 . A method, comprising
 by capillarity, conducting a liquid from which fibers are to be formed by electrospinning through an integrated porous body, the liquid being conducted from base ends of elements of the integrated porous body to free ends of the elements, and   electrospinning the fibers from the free ends of the elements.