Method for the prevention of nanoparticle agglomeration at high temperatures

Abstract

A method includes: (a) conformally depositing a barrier coating, provided in liquid form, on at least one surface of a substrate; (b) embedding a plurality of nanoparticles in the barrier coating to a selected depth; and (c) fully curing the barrier coating after embedding the plurality of nanoparticles; the embedded plurality of nanoparticles are in continuous contact with the cured barrier coating. The order in which the barrier coating and nanoparticles are deposited on the substrate can be switched or they can be deposited simultaneously. An article includes a substrate having a cured barrier coating conformally disposed on at least one surface of the substrate and a plurality of nanoparticles embedded to a selected depth in the barrier coating creating an embedded portion of each of the plurality of nanoparticles. The embedded portion of each of the plurality of nanoparticles in continuous contact with the cured barrier coating.

1 . A method comprising:
 (a) conformally depositing a barrier coating on at least one surface of a substrate; said barrier coating provided in liquid form;   (b) embedding a plurality of nanoparticles in said barrier coating to a selected depth creating an embedded portion of each of said plurality of nanoparticles; and   (c) fully curing said barrier coating after embedding said plurality of nanoparticles; said embedded portion of each of said plurality of nanoparticles being in continuous contact with said cured barrier coating.   
     
     
         2 . The method of  claim 1 , wherein conformally depositing said barrier coating and embedding said plurality of nanoparticles is performed simultaneously. 
     
     
         3 . The method of  claim 1 , wherein a thickness of said barrier coating is about the same or less than the effective diameter of said plurality of nanoparticles. 
     
     
         4 . The method of  claim 1 , wherein a thickness of said barrier coating is in a range from between about the same as the effective diameter of said plurality of nanoparticles up to about 5,000% greater than the effective diameter of said plurality of nanoparticles. 
     
     
         5 . The method of  claim 1 , wherein said substrate is treated with a plasma prior to conformally depositing said barrier coating. 
     
     
         6 . The method of  claim 1 , wherein said embedded plurality of nanoparticles maintain an exposed surface when said plurality of nanoparticles are in surface contact with said substrate. 
     
     
         7 . The method of  claim 1 , wherein the step of depositing said barrier coating is accomplished by a technique selected from dip coating and spraying. 
     
     
         8 . The method of  claim 1 , wherein said barrier coating comprises a material selected from a siloxane, a silane, an alumina, a silicon carbide ceramic, and a metal; said barrier coating being chosen for its ability to adhere to said substrate. 
     
     
         9 . The method of  claim 1  further comprising partially curing said barrier coating prior to embedding said plurality of nanoparticles. 
     
     
         10 . The method of  claim 1 , wherein said substrate is selected from the group consisting of a metal, a ceramic, a silica wafer, a fiber, a graphite sheet, and a high temperature plastic. 
     
     
         11 . The method of  claim 1  further comprising heating the environment about said embedded plurality of nanoparticles, in the presence of a feedstock material, to a temperature promoting growth of a plurality of nanostructures from said feedstock material, said embedded plurality of nanoparticles catalyzing said growth; wherein the temperature is sufficient to cause agglomeration of said plurality of nanoparticles in the absence of said barrier coating. 
     
     
         12 . The method of  claim 11 , wherein said nanoparticles comprise a transition metal. 
     
     
         13 . The method of  claim 11 , wherein said feedstock material is a carbon source. 
     
     
         14 . The method of  claim 11 , wherein said nanostructure is a carbon nanotube. 
     
     
         15 . The method of  claim 1 , wherein said nanoparticles comprise a clay. 
     
     
         16 . The method of  claim 1 , wherein said nanoparticles comprise silica or alumina. 
     
     
         17 . The method of  claim 1 , wherein said nanoparticles range in size from between about 0.5 nm to about 500 nm. 
     
     
         18 . A method comprising:
 (a) depositing a plurality of nanoparticles on at least one surface of a substrate;   (b) conformally depositing a barrier coating over said substrate and at least a portion of each of said plurality of nanoparticles, creating an embedded portion of each of said plurality of nanoparticles, said barrier coating provided in liquid form; and   (c) fully curing said barrier coating;
 wherein said plurality of nanoparticles are in surface contact with said substrate and said embedded portion of each of said plurality of nanoparticles is in continuous contact with said cured barrier coating. 
   
     
     
         19 . The method of  claim 18 , wherein a thickness of said barrier coating is about the same or less than the effective diameter of said plurality of nanoparticles. 
     
     
         20 . The method of  claim 18 , wherein a thickness of said barrier coating is in a range from between about the same as the effective diameter of said plurality of nanoparticles up to about 100% greater than the effective diameter of said plurality of nanoparticles. 
     
     
         21 . The method of  claim 18 , wherein said substrate is treated with a plasma prior to depositing said plurality of nanoparticles. 
     
     
         22 . The method of  claim 18 , wherein the step of depositing said barrier coating is accomplished by a technique selected from dip coating and spraying. 
     
     
         23 . The method of  claim 18 , wherein said barrier coating comprises a material selected from a siloxane, a silane, an alumina, a silicon carbide ceramic, and a metal; said barrier coating being chosen for its ability to adhere to said substrate. 
     
     
         24 . The method of  claim 18 , wherein said substrate is a metal, a ceramic, a silica wafer, a fiber, a graphite sheet, and a high temperature plastics. 
     
     
         25 . The method of  claim 18  further comprising heating the environment about said embedded plurality of nanoparticles, in the presence of a feedstock material, to a temperature promoting catalyzed growth of a plurality of nanostructures from said feedstock material, said embedded plurality of nanoparticles catalyzing said growth; wherein the temperature is sufficient to cause agglomeration of said plurality of nanoparticles in the absence of said barrier coating. 
     
     
         26 . The method of  claim 25 , wherein said plurality of nanoparticles comprise a transition metal. 
     
     
         27 . The method of  claim 25 , wherein said feedstock material is a carbon source. 
     
     
         28 . The method of  claim 25 , wherein said nanostructure is a carbon nanotube. 
     
     
         29 . The method of  claim 18 , wherein said nanoparticles comprise a clay. 
     
     
         30 . The method of  claim 18 , wherein said nanoparticles comprise silica or alumina. 
     
     
         31 . The method of  claim 18 , wherein said nanoparticles range in size from between about 0.5 nm to about 500 nm. 
     
     
         32 . An article comprising:
 a substrate having a cured barrier coating conformally disposed on at least one surface of said substrate; and   a plurality of nanoparticles embedded to a selected depth in said barrier coating creating an embedded portion of each of said plurality of nanoparticles, said embedded portion of each of said plurality of nanoparticles in continuous contact with said cured barrier coating.   
     
     
         33 . The article of  claim 32 , wherein said embedded plurality of nanoparticles are in surface contact with said substrate. 
     
     
         34 . The article of  claim 32 , wherein said barrier coating comprises a material selected from a siloxane, a silane, an alumina, a silicon carbide ceramic, and a metal; said barrier coating being chosen for its ability to adhere to said substrate. 
     
     
         35 . The article of  claim 32 , wherein said substrate is selected from the group consisting of a metal, a ceramic, a silica wafer, a fiber, a graphite sheet, and a high temperature plastic 
     
     
         36 . The article of  claim 32 , wherein said plurality of nanoparticles comprise a transition metal. 
     
     
         37 . The article of  claim 32 , wherein said plurality of nanoparticles comprise a clay. 
     
     
         38 . The article of  claim 32 , wherein said plurality of nanoparticles comprise silica or alumina. 
     
     
         39 . The article of  claim 32 , wherein said nanoparticles range in size from between about 0.5 nm to about 500 nm. 
     
     
         40 . The article of  claim 32 , wherein a thickness of said barrier coating is about the same or less than the effective diameter of said plurality of nanoparticles. 
     
     
         41 . The article of  claim 32 , wherein a thickness of said barrier coating is in a range from between about the same as the effective diameter of said plurality of nanoparticles up to about 5000% greater than the effective diameter of said plurality of nanoparticles.