Micro-Vascular Materials And Composites For Forming The Materials

Abstract

A microvascular system includes a solid polymeric matrix and a woven structure in the matrix. The woven structure includes a plurality of fibers, and a plurality of microfluidic channels, where at least a portion of the microfluidic channels are interconnected. The microvascular system may be made by forming a composite that includes a solid polymeric matrix and a plurality of sacrificial fibers in the matrix, heating the composite to a temperature of from 100 to 250° C., maintaining the composite at a temperature of from 100 to 250° C. for a time sufficient to form degradants from the sacrificial fibers, and removing the degradants from the composite. The sacrificial fibers may include a polymeric fiber matrix including a poly(hydroxyalkanoate) and a metal selected from the group consisting of an alkali earth metal and a transition metal, in the fiber matrix, where the concentration of the metal in the fiber matrix is at least 0.1 wt %.

1 . A microvascular system, comprising:
 a solid polymeric matrix;   a woven structure in the matrix, the woven structure comprising
 a plurality of fibers, and 
 a plurality of microfluidic channels, 
   where at least a portion of the microfluidic channels are interconnected.   
     
     
         2 . The microvascular system of  claim 1 , where the woven structure comprises warp threads and weft threads in a 2D woven structure, and at least a portion of the microfluidic channels are present as weft threads. 
     
     
         3 . The microvascular system of  claim 1 , where the woven structure comprises warp threads, weft threads and Z-threads in a 3D woven structure, and at least a portion of the microfluidic channels are present as weft threads or as Z-threads. 
     
     
         4 . The microvascular system of  claim 1 , where the microfluidic channels have an average diameter of from 20 to 500 micrometers. 
     
     
         5 . The microvascular system of  claim 1 , where the fibers are selected from the group consisting of carbon fibers and glass fibers. 
     
     
         6 . The microvascular system of  claim 1 , where the solid polymer matrix comprises a polymer selected from the group consisting of a polyamide, a polyester, a polycarbonate, a polyether, an epoxy polymer, an epoxy vinyl ester polymer, a polyimide, an amine-formaldehyde polymer, a polysulfone, a poly(acrylonitrile-butadiene-styrene), a polyurethane, a polyolefin, a polyacrylate, a poly(alkylacrylate), a polysilane, a polyphosphazene. 
     
     
         7 . The microvascular system of  claim 1 , where the solid polymer matrix comprises an elastomer. 
     
     
         8 . The microvascular system of  claim 1 , where the interconnected microfluidic channels comprise a fluid. 
     
     
         9 . A method of making a microvascular system, comprising:
 forming a composite comprising
 a solid polymeric matrix, and 
 a plurality of sacrificial fibers in the matrix; 
   heating the composite to a temperature of from 100 to 250° C.;   maintaining the composite at a temperature of from 100 to 250° C. for a time sufficient to form degradants from the sacrificial fibers,
 the degradants having an average molecular weight less than 500 Daltons; and 
   removing the degradants from the composite to provide a network of microfluidic channels.   
     
     
         10 . The method of  claim 9 , where the forming comprises:
 contacting the sacrificial fibers with a matrix precursor; and   heating the matrix precursor to a temperature of at least 75° C. for a time sufficient to form the polymeric matrix.   
     
     
         11 . The method of  claim 9 , where the sacrificial fibers comprise
 a polymeric fiber matrix comprising a poly(hydroxyalkanoate); and   a metal selected from the group consisting of an alkali earth metal and a transition metal, in the fiber matrix;   where the concentration of the metal in the fiber matrix is at least 0.1 wt %.   
     
     
         12 . A method of making a microvascular system, comprising:
 forming a composite comprising
 a solid polymeric matrix, and 
 a woven structure in the matrix, the woven structure comprising a plurality of fibers, and a plurality of sacrificial fibers; 
   heating the composite to a temperature of from 100 to 250° C.;   maintaining the composite at a temperature of from 100 to 250° C. for a time sufficient to form degradants from the sacrificial fibers,
 the degradants having an average molecular weight less than 500 Daltons; and 
   removing the degradants from the composite to provide a plurality of microfluidic channels.   
     
     
         13 . The method of  claim 12 , where the woven structure comprises warp threads and weft threads in a 2D woven structure, and at least a portion of the sacrificial fibers are present as weft threads. 
     
     
         14 . The method of  claim 12 , where the woven structure comprises warp threads, weft threads and Z-threads in a 3D woven structure, and at least a portion of the sacrificial fibers are present as weft threads or as Z-threads. 
     
     
         15 . The method of  claim 12 , where the forming comprises:
 contacting the sacrificial fibers with a matrix precursor; and   heating the matrix precursor to a temperature of at least 75° C. for a time sufficient to form the polymeric matrix.   
     
     
         16 . The method of  claim 12 , where the sacrificial fibers comprise
 a polymeric fiber matrix comprising a poly(hydroxyalkanoate); and   a metal selected from the group consisting of an alkali earth metal and a transition metal, in the fiber matrix;   where the concentration of the metal in the fiber matrix is at least 0.1 wt %.   
     
     
         17 . The method of  claim 12 , where at least a portion of the microfluidic channels are interconnected. 
     
     
         18 . A thermally degradable polymeric fiber, comprising:
 a polymeric fiber matrix comprising a poly(hydroxyalkanoate); and   a metal selected from the group consisting of an alkali earth metal and a transition metal, in the fiber matrix;   where the concentration of the metal in the fiber matrix is at least 0.1 wt %.   
     
     
         19 - 24 . (canceled) 
     
     
         25 . A method of making a degradable polymeric fiber, comprising:
 combining
 a fiber comprising a poly(hydroxyalkanoate) and 
 a composition comprising a fluorinated fluid and a metal selected from the group consisting of an alkali earth metal and a transition metal; 
   maintaining the fiber and the composition together at a temperature and for a time sufficient to provide a concentration of the metal in the fiber of at least 0.1 wt %; and   separating the fiber and the fluorinated fluid.   
     
     
         26 - 28 . (canceled) 
     
     
         29 . A method of making a degradable polymeric fiber, comprising:
 forming a spinning liquid comprising a poly(hydroxyalkanoate), a solvent, and a metal selected from the group consisting of an alkali earth metal and a transition metal;   passing the spinning liquid through a spinneret to form a fiber comprising the poly(hydroxyalkanoate) and the metal; and   drying the fiber to provide a concentration of the metal in the fiber of at least 0.1 wt %.   
     
     
         30 - 33 . (canceled)