Micro-Vascular Materials And Composites For Forming The Materials
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)