process for preparing microrods using liquid-liquid dispersion

Abstract

The invention provides a method for forming polymer microrods, the method including the steps of providing a polymer solution comprising a polymer dissolved in a first solvent; providing a dispersion medium comprising a second solvent, wherein the first solvent and the second solvent are miscible or partially soluble in each other, and wherein the polymer is insoluble in the second solvent; adding the polymer solution to the dispersion medium to form a dispersed phase of polymer solution droplets within the dispersion medium; and introducing a shear stress to the dispersion medium and dispersed polymer solution droplets for a time and at a shear rate sufficient to elongate the polymer solution droplets to form microrods and solidify the microrods by attrition of the polymer solvent into the dispersion medium.

1 . A plurality of polymer microrods having an average aspect ratio of at least about 5, an average length of about 10 to about 100 μm, and an average diameter of about 0.1 to about 10 μm. 
   
   
       2 . The plurality of polymer microrods of  claim 1 , wherein the average aspect ratio is at least about 20. 
   
   
       3 . The plurality of polymer microrods of  claim 1 , wherein the average length is about 10 to about 50 μm. 
   
   
       4 . The plurality of polymer microrods of  claim 1 , wherein the average diameter is about 0.5 to about 3 μm. 
   
   
       5 . The plurality of polymer microrods of  claim 1 , wherein the microrods comprise a polymer selected from the group consisting of polyolefin, polyether, polyamide, polyamideimide, polyarylate, polybenzimidazole, polyester, polyurethane, polyimide, polyhydrazide, phenolic resins, polysilane, polysiloxane, polycarbodiimide, polyimine, azo polymers, polysulfide, polysulfone, copolymers thereof, and mixtures thereof. 
   
   
       6 . The plurality of polymer microrods of  claim 1 , wherein the microrods comprise a polymer selected from the group consisting of polyethylene, polypropylene, poly(vinyl chloride), polystyrene, polytetrafluoroethylene, poly(α-methylstyrene), poly(acrylic acid), poly(isobutylene), poly(acrylonitrile), poly(methacrylic acid), poly(methyl methacrylate), poly(1-pentene), poly(1,3-butadiene), poly(vinyl acetate), poly(2-vinyl pyridine), 1,4-polyisoprene, 3,4-polychloroprene, poly(ethylene oxide), polyformaldehyde, polyacetaldehyde, poly(3-propionate), poly(10-decanoate), poly(ethylene terephthalate), polycaprolactam, poly(11-undecanoamide), poly(hexamethylene sebacamide), poly(m-phenylene terephthalate), and poly(tetramethylene-m-benzenesulfonamide). 
   
   
       7 . The plurality of polymer microrods of  claim 1 , wherein the microrods comprise an epoxy resin. 
   
   
       8 . The plurality of polymer microrods of  claim 1 , wherein the microrods comprise a naturally-occurring polymer. 
   
   
       9 . The plurality of polymer microrods of  claim 1 , wherein the microrods comprises a particulate material imbedded therein. 
   
   
       10 . The plurality of polymer microrods of  claim 9 , wherein the particulate material comprises silica or magnetic particles. 
   
   
       11 . The plurality of polymer microrods of  claim 1 , wherein the polymer microrods can be rotated or aligned by application of an external electric or magnetic field. 
   
   
       12 . The plurality of polymer microrods of  claim 1 , wherein the polymer microrods are anisotropic. 
   
   
       13 . The plurality of polymer microrods of  claim 1 , wherein the polymer microrods are crosslinked. 
   
   
       14 . A material selected from the group consisting of liquid crystal materials, nonwoven textiles, paper materials, porous fibrillar materials, pads, linings, sponges, filters, food products, paints, pharmaceutical compositions, cosmetics, bath products, latex foams, polyurethane foams, and fibrillar matrices for cell attachment, the material comprising a plurality of polymer microrods according to  claim 1 . 
   
   
       15 . The material of  claim 14 , wherein the material is a food product selected from the group consisting of ice cream, mayonnaise, salad dressings, and whipped cream. 
   
   
       16 . The material of  claim 14 , wherein the material is a pharmaceutical composition comprising the polymer microrods in the form of colloidosome microcapsules.