In-situ and ex-situ electrophoresis-based formation of aligned nanostructure triggers for solid explosives

Abstract

An electrophoresis process is used to form a more efficient and controllable triggering mechanism for solid explosives ignited through the application of electromagnetic energy. Electrophoresis is used to overcome the Van der Waals forces that hold the nanostructures together to disperse and align the nanostructures to the field lines of an applied electric field in-situ in the explosive or ex-situ in a pre-preg layer (or layers) that is then introduced to the explosive. The in-situ process requires fewer steps but is more constrained in the trigger structures that can be formed and care must be taken not to detonate the explosive during the electrophoresis process. The ex-situ process requires additional steps but provides greater flexibility to create trigger structures and the electrophoresis process is performed on a lower viscosity non-explosive material.

1 . A process for forming a solid explosive ignited by exposure to electromagnetic energy, comprising:
 placing a mass of conductive nanostructures in an uncured pre-preg host solution;   applying an electric field to disperse and align the nanostructures in the uncured host solution with the field lines via electrophoresis;   while the electric field is applied, curing the host solution to form a pre-preg layer including an aligned nanostructure trigger;   placing the pre-preg layer in an uncured explosive solution;   heating the explosive solution to remove the pre-preg host; and   curing the explosive solution to form a solid explosive with an impregnated aligned nanostructure trigger.   
   
   
       2 . The process of  claim 1 , wherein the nanostructures have at least one dimension less than one micron and have an aspect ratio greater than one. 
   
   
       3 . The process of  claim 2 , wherein the nanostructures have an aspect ratio greater than ten. 
   
   
       4 . The process of  claim 2 , wherein the nanostructures comprise nanotubes or nanowires. 
   
   
       5 . The process of  claim 1 , wherein the electric field is approximately uniform, said nanostructures dispersing towards and aligning with the approximately uniform field lines. 
   
   
       6 . The process of  claim 5 , wherein the electric field is no greater than 10 V/cm. 
   
   
       7 . The process of  claim 5 , further comprising setting the strength of the applied electric field to produce a desired spacing of field lines and nanostructures. 
   
   
       8 . The process of  claim 1 , wherein the uncured host solution has a low viscosity to allow movement of the nanostructures in the electric field and the uncured explosive has a high viscosity to inhibit reaggregation of the nanostructures prior to curing of the explosive. 
   
   
       9 . The process of  claim 1 , wherein the pre-preg host has a lower vapor point than the explosive. 
   
   
       10 . The process of  claim 1 , wherein the conductivity of the nanostructures is at least ten times the conductivity of the solid explosive. 
   
   
       11 . The process of  claim 1 , wherein the solid explosive comprises one or more of PETN, RDX, HMX and TNT. 
   
   
       12 . The process of  claim 1 , further comprising:
 placing a waveguide around the solid explosive.   
   
   
       13 . The process of  claim 1 , further comprising:
 placing a plurality of pre-preg layers in the uncured explosive.   
   
   
       14 . The process of  claim 13 , wherein the plurality of pre-preg layers are disbursed throughout the volume of the uncured explosive. 
   
   
       15 . The process of  claim 13 , where the plurality of pre-preg layers are laminated so then when the pre-preg host is removed the aligned nanostructures triggers merge to form a single trigger. 
   
   
       16 . The process of  claim 1 , further comprising:
 exposing the solid explosive to electromagnetic radiation that couples to the aligned nanostructure trigger to heat the nanostructures and initiate a volumetric explosion of the explosive.   
   
   
       17 . The process of  claim 16 , wherein the aligned nanostructure trigger exhibits preferential coupling to a specified band of electromagnetic radiation, said explosive being exposed to electromagnetic radiation in the specified band. 
   
   
       18 . The process of  claim 1 , further comprising:
 providing a source proximate the solid explosive, said source configured to expose the solid explosive to a band of electromagnetic radiation that couples to the aligned nanostructure trigger to heat the nanostructures and initiate a volumetric explosion of the explosive; and   forming a Faraday cage around the explosive and source, said Faraday cage configured to block external electromagnetic radiation in said band from initiating detonation of the explosive.   
   
   
       19 . A process for forming a solid explosive ignited by exposure to electromagnetic energy, comprising:
 (a) placing a mass of conductive nanostructures in an uncured pre-preg host solution, said nanostructures having at least one dimension less than a micron and an aspect ratio greater than one;   (b) applying an electric field to disperse and align the nanostructures in the uncured host solution with the field lines via electrophoresis;   (c) while the electric field is applied, curing the host solution to form a pre-preg layer including a pattern of aligned nanostructures;   (d) repeating steps a through c at least once;   (e) placing the pre-preg layers to form a laminate in an uncured explosive solution in which the pre-preg layers as placed present different patterns of aligned nanostructures;   (f) heating the explosive solution to remove the pre-preg hosts, said patterns of aligned nanostructures merging to form an aligned nanostructure trigger; and   (g) curing the explosive solution to form a solid explosive with an impregnated aligned nanostructure trigger.   
   
   
       20 . The process of  claim 19 , wherein the aligned nanostructure trigger includes lines of nanostructures that are not approximately parallel to each other. 
   
   
       21 . The process of  claim 19 , wherein the aligned nanostructure trigger exhibits preferential coupling to a specific band of electromagnetic energy. 
   
   
       22 . The process of  claim 19 , wherein a different electric field is applied to disperse and align the nanostructures in at least one pre-preg layer to produce a different pattern of aligned nanostructures. 
   
   
       23 . The process of  claim 19 , wherein at least one pre-preg layer is translated or rotated when placed in the uncured explosive solution to produce a different pattern of aligned nanostructures. 
   
   
       24 . A process for forming a solid explosive ignited by exposure to electromagnetic energy, comprising:
 placing a mass of conductive nanostructures in an uncured explosive solution;   applying an electric field to disperse and align the nanostructures in the uncured explosive solution with the field lines via electrophoresis; and   while the electric field is applied, curing the explosive solution to form a solid explosive impregnated with an aligned nanostructure trigger.   
   
   
       25 . The process of  claim 24 , wherein the nanostructures comprise nanotubes or nanowires having at least one dimension less than one micron and have an aspect ratio greater than ten and having a conductivity at least ten times the conductivity of the solid explosive. 
   
   
       26 . The process of  claim 24 , wherein the applied electric field is substantially uniform. 
   
   
       27 . The process of  claim 24 , further comprising:
 providing a source proximate the solid explosive, said source configured to expose the solid explosive to a band of electromagnetic radiation that couples to the aligned nanostructure trigger to heat the nanostructures and initiate a volumetric explosion of the explosive; and   forming a Faraday cage around the explosive and source, said Faraday cage configured to block external electromagnetic radiation in said band from initiating detonation of the explosive.