Electro spinning of submicron diameter polymer filaments

Claims

• What is claimed is: 1. An electro spinning process for extruding a thread-forming polymer and drawing between an electrically charged die, having a first electrical bias and a first polarity and an electrically charged collecting means to produce a continuous polymer filament, comprising the steps of: liquefying the thread-forming polymer and extruding through a die orifice to form a liquid-state filament, drawing the liquid-state filament through a longitudinally sequentially biased electrostatic field having the same polarity as the first polarity, thereby imparting a bias gradient to the liquid-state filament, solidifying the liquid-state filament to form a linearly oriented solid polymer filament, and collecting the solid polymer filament on the collecting means. 2. The electro spinning process of claim 1 wherein the die and electrostatic field are positively biased and the collecting means is negatively biased. 3. The electro spinning process of claim 1 wherein the die and charged electrostatic field are positively biased and the collecting means is grounded. 4. The electro spinning process of claim 1 wherein the longitudinally sequentially biased field gradient has a length of 3 centimeters or more. 5. The electro spinning process of claim 1 wherein the longitudinally sequentially biased field gradient has a length of 3 to 100 centimeters. 6. The electro spinning process of claim 1 wherein the longitudinally sequentially biased field gradient is linearly charged. 7. The electro spinning process of claim 1 wherein the longitudinally sequentially biased field gradient is linearly charged to 10,000 to 300,000 volts/meter. 8. The electro spinning process of claim 1 wherein the longitudinally sequentially biased field gradient is linearly charged to 50,000 to 250,000 volts/meter. 9. The method of claim 1 wherein the polymer filament is extruded to a diameter of 100 to 500 nanometers.