Electrophoretic deposition of hexagonal boron nitride films and coatings and their applications

Abstract

Embodiments relate to methods for preparing a hexagonal boron nitride (hBN) suspension and forming films, coatings, or membranes via electrophoretic deposition.

What is claimed is: 
     
         1 . A method for preparing a hexagonal boron nitride (hBN) suspension, the method comprising:
 performing steps of:
 mixing and dissolving a metal in a solvent to form a mixture, wherein the solvent includes (A) a polar aprotic organic solvent, (A′) a mixture of polar aprotic organic solvents, or (B) ammonia; and 
 dispersing hBN powder containing one or more hBN sheet or exfoliated hBN powder containing one or more hBN sheet in the mixture, wherein the metal provides a counterion to negatively charge the one or more hBN sheet; 
   or;   performing steps of:
 combining hBN powder containing one or more hBN sheet or exfoliated hBN powder containing one or more hBN sheet with a metal to form a mixture, wherein the metal provides a counterion to negatively charge the one or more hBN sheet; 
 applying heat to the mixture to generate a metal-intercalated hBN material; and 
 exposing the metal-intercalated hBN material to a solvent, the solvent including (A) a polar aprotic organic solvent, (A′) a mixture of polar aprotic organic solvents, or (B) ammonia; 
   or;   performing steps of:
 combining hBN powder containing one or more hBN sheet or exfoliated hBN powder containing one or more hBN sheet and a polyelectrolyte to form a mixture; 
 dispersing the mixture in an organic polar aprotic a solvent, the solvent including (A) a polar aprotic organic solvent, (A′) a mixture of polar aprotic organic solvents, or (B) ammonia, wherein the polyelectrolyte adsorbs onto the hBN and to impart a negative charge to the one or more hBN sheet. 
   
     
     
         2 . The method of  claim 1 , wherein:
 the metal is one or more alkali metals, one or more alkaline earth metals, one or more alkali metal electrides, one or more alkaline earth metal electrides, or a combination thereof.   
     
     
         3 . The method of  claim 1 , wherein:
 the metal is Li, K, Na, R, Cs, Fr, Be, Mg, Ca, Ba, Sr, and/or Ra.   
     
     
         4 . The method of  claim 1 , wherein:
 the counterion is Li + , K + , Na, Rb + , Cs + , Fr + , Be 2+ , Mg 2+ , Ca 2+ , Ba 2+ , Sr 2+ , and/or Ra 2+ .   
     
     
         5 . The method of  claim 1 , wherein:
 the polyelectrolyte is a nucleic acid, a protein, a teichoic acid, a polypeptides, and/or a polysaccharide.   
     
     
         6 . The method of  claim 1 , wherein:
 the solvent is tetrahydrofuran (THF), acetone, acetonitrile, dimethoxyethane (DME), sulfolane, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylpyrrolidone (NMP), N-methylformamide, acetone, acetonitrile, dichloromethane, dimethylformamide (DMF), dimethylpropyleneurea, and/or ethyl acetate, hexamethylphosphoric triamide.   
     
     
         7 . The method of  claim 1 , wherein:
 mixing and dispersing occur for a duration within a range from 0 hours to 96 hours;   mixing and dispersing occur while the mixture is subjected to a temperature within a range from −22° C. to 220° C.   
     
     
         8 . The method of  claim 1 , wherein:
 concentration of the exfoliated hBN in the hBN suspension is within a range from 0.01 g/L to 10 g/L.   
     
     
         9 . The method of  claim 1 , further comprising:
 separating the hBN suspension from the mixture via centrifugation.   
     
     
         10 . A method of depositing hexagonal boron nitride (hBN) on a substrate, the method comprising:
 placing an anode electrode in an environment containing an exfoliated hBN suspension, the exfoliated hBN suspension including one or more negatively charged hBN sheets, the anode comprising the substrate;   placing a cathode electrode in the environment;   applying a voltage difference across the anode electrode and the cathode electrode;   forming, via electrophoretic deposition, a hBN film, coating, and/or membrane on at least a portion of the substrate.   
     
     
         11 . The method of  claim 10 , wherein:
 the hBN film, coating, and/or membrane is formed directly on a surface of the substrate; and/or   the hBN film, coating, and/or membrane is formed on a layer of material formed on the substrate.   
     
     
         12 . The method of  claim 11 , wherein:
 the material includes any one or combination of graphene, MoS 2 , or WS 2 .   
     
     
         13 . The method of  claim 10 , wherein:
 the hBN film, coating, and/or membrane is used as an anticorrosion coating, an antioxidation coating, a lubricant coating, an insulating coating, a thermally or electrically conductive coating, a heat dissipation coating, and/or a dielectric coating for the substrate.