Dry-jet wet-spinning of multifunctional carbon fibers

Abstract

A carbonized coaxial composite fiber includes an inner layer including carbonized polyacrylonitrile, a middle layer surrounding the inner layer and including carbonized graphene nanomaterials, and an exterior layer surrounding the middle layer including carbonized polyacrylonitrile. The carbonized graphene nanomaterials are aligned along a length of the coaxial composite fiber.

What is claimed is: 
     
         1 . A carbonized coaxial composite fiber comprising:
 an inner layer comprising carbonized polyacrylonitrile;   a middle layer surrounding the inner layer and comprising carbonized graphene nanomaterials, wherein the graphene nanomaterials comprise graphene nanoplatelets, graphene nanoribbons, graphene nanochips, or any combination thereof; and   an exterior layer surrounding the middle layer comprising carbonized polyacrylonitrile,   wherein the carbonized graphene nanomaterials are aligned along a length of the coaxial composite fiber.   
     
     
         2 . The fiber of  claim 1 , wherein the middle layer further comprises carbonized polyacrylonitrile. 
     
     
         3 . The fiber of  claim 2 , wherein the middle layer is formed from a mixture comprising the polyacrylonitrile and the graphene nanomaterials, and a weight ratio of the polyacrylonitrile to the graphene nanomaterials in the mixture is in a range of 1:15 to 15:1. 
     
     
         4 . The fiber of  claim 3 , wherein the middle layer defines voids between the carbonized graphene nanomaterials. 
     
     
         5 . The fiber of  claim 1 , wherein the voids are at least partially filled with polyacrylonitrile. 
     
     
         6 . The fiber of  claim 1 , wherein the inner layer and the outer layer consist of polyacrylonitrile. 
     
     
         7 . The fiber of  claim 1 , wherein a diameter of the coaxial composite fiber is in a range of about 50 microns to about 500 microns. 
     
     
         8 . The fiber of  claim 7 , wherein a diameter of the inner layer is in a range of about 20 microns to about 80 microns. 
     
     
         9 . The fiber of  claim 7 , wherein a thickness of the middle layer is in a range of about 20 microns to about 10 microns. 
     
     
         10 . The fiber of  claim 7 , wherein a thickness of the outer layer is in a range of about 10 microns to about 50 microns. 
     
     
         11 . A method of forming the coaxial composite fiber of  claim 1 , the method comprising:
 forming a coagulated gel precursor fiber by extruding a multiplicity of solutions through a multiphase spinneret through an air gap and into a solvent, wherein the coagulated gel precursor fiber comprises:
 an inner layer comprising polyacrylonitrile; 
 a middle layer comprising graphene nanomaterials, wherein the graphene nanomaterials comprise graphene nanoplatelets, graphene nanoribbons, graphene nanochips, or any combination thereof; and 
 an outer layer comprising polyacrylonitrile; 
   hot drawing the coagulated gel precursor fiber to yield a drawn precursor fiber;   oxidizing the drawn precursor fiber to yield a stabilized fiber; and   carbonizing the stabilized fiber to yield the coaxial composite fiber.   
     
     
         12 . The method of  claim 11 , wherein the multiplicity of solutions comprises a first solution, a second solution, and a third solution corresponding to the inner layer, the middle layer, and the outer layer, respectively. 
     
     
         13 . The method of  claim 12 , wherein the first solution and the third solution comprise polyacrylonitrile. 
     
     
         14 . The method of  claim 13 , wherein the first solution and the third solution are the same. 
     
     
         15 . The method of  claim 12 , wherein the second solution comprises graphene nanomaterials. 
     
     
         16 . The method of  claim 15 , wherein the second solution further comprises polyacrylonitrile. 
     
     
         17 . The method of  claim 16 , wherein a weight ratio of the polyacrylonitrile to the graphene nanomaterials is in a range of 1:15 to 15:1. 
     
     
         18 . The method of  claim 12 , wherein the first solution, the second solution, and the third solution comprise dimethylformamide. 
     
     
         19 . The method of  claim 11 , wherein the solvent comprises methanol. 
     
     
         20 . The method of  claim 11 , wherein hot drawing the coagulated gel precursor fiber comprises heating the coagulated gel precursor fiber above the glass transition temperature of polyacrylonitrile.