TECHNOLOGY FOCUS - POLYMERS - Preferred Process: The method of preparing hollow fibers from non-polymer materials and of external diameter 20-100 nm comprises:(1) preparation of a porous template material;(2) introduction of at least one polymer containing liquid into the pores of the template material so that the pore walls are wetted by the liquid, but not completely filled by it;(3) solidification of the liquid;(4) selective, optionally at least partial removal of the template material;(5) optionally chemical transformation of the non-polymer material remaining in the pores; and(6) optionally, at least partial removal of the template material.The liquid is introduced into the pores as a melt of a polymer or mixture of polymers, optionally containing other additives. The melt is obtained by heating to a temperature above, e.g. at least 30% above the solidification temperature of the polymer or polymer mixture. A liquid is introduced into the carrier or carrier mixture, optionally containing other additives, as a solution, suspension, and/or emulsion.Hollow fibers are prepared with at least two co-existing phases and at least one phase is selectively removed from the hollow fibers, preferably by extraction, radiation, chemical, biological, or thermal degradation, action of ultrasonics, or a combination of these.Preferred Components: The liquid contains at least one partially crystalline or crystalline component and the degree of crystallization of the hollow fibers is set by tempering the filled template material over a selected time period at a selected temperature above the glass transition temperature and below the melt temperature of the partially crystalline or crystalline component and/or by cooling the melt at a selected cooling rate. A phase transition process is brought about in the pore walls of the material used. The hollow fibers can be arranged in a regular order, preferably hexagonal, trigonal, or quadratic.The polymer is selected from:(1) organic polymers, e.g. poly(p-xylylenes), polyetherimides, polyacrylamides, polyacrylimides, and at least 46 other compounds;(2) biological polymers, e.g. cellulose, alginates, or polypeptides, e.g. collagen;(3) polymers obtained from two or more repeating units, preferably in the form of block copolymers, graft copolymers, or dendrimers; and(4) combinations of several organic polymers and/or biological polymers.The hollow fibers contain at least one non-polymer material, and are constant in diameter over the whole of their length. Both ends of the hollow fibers are open, one fiber end is open, or both fiber ends are closed, enclosing a hollow space. The specific surface of the hollow fibers is greater than 10, preferably greater than 500 m2/g, and the surface to volume ratio of the hollow fibers is greater than 100, preferably greater than 10,000 m2/m2/m3.The aspect ratio of the hollow fibers is not less than 100, preferably not less than 10,000. The hollow fibers contain at least two different polymers in selected mixing ratios. The hollow fibers contain at least one partially crystalline or crystalline component of degree of crystallinity less than 40, preferably less than 5%, or greater than 40, preferably greater than 85. After solidification of the liquid the template material is partially degraded biologically, thermally or chemically, by radiation, photochemically, via a plasma, by treatment with ultrasonics or microwaves, or/and solvent extraction. EXAMPLE - In the production of porous polystyrene (PS) nanotubes, a 2.4 wt.% solution of polystyrene in methylene chloride was applied to an aluminum oxide membrane (pore diameter 200 nm, pore length 50 microm), and the polymer was solidified by evaporating off the solvent, giving pores of diameter 100 nm in the pore envelope surface of the PS in the template. The template was removed by treatment with aqueous potassium hydroxide, and the nanotubes obtained had pores of diameter about 100 nm in their envelope surface.