Method of making microporous structure defined by a multiplicity of singular channels

A method of forming a microporous structure comprising an axially extended outer wall that surrounds a plurality of singular micro-passages defined by internal walls and wherein the micro-passages extend along the axial length of the outer wall, the method comprising:

• a) inserting a plurality of conduits into a surrounding tube to form a tube and conduit assembly wherein the conduits have relatively small internal and external diameters relative to the tube;
• b) sealing the common openings of the conduits about one end of the tube and conduit assembly to form a drawing preform having a closed end about which all conduits are sealed from fluid flow and an opposite open end about which all conduits are open for fluid flow;
• c) heating the drawing preform to a softening temperature that permits plastic flow of the drawing stock under an axial traction force but inhibits plastic flow of the drawing stock under its own weight;
• d) simultaneously drawing the drawing preform by application of a tractor while maintaining the preform at the softening temperature and restricting fluid flow from the open end to reduce the interiors of the conduits to a micropore size while preventing collapsing closure of the conduit interiors;
• and,
• e) collecting a microporous structure from the drawn drawing stock that has a plurality of singular micro-passages defined by internal walls and substantially equal in number to the number of conduits.