Nanophase Technologies Corporation

John H Aikens

Richard W Brotzman, Jr

Harry W Sarkas

Sara Helvoigt

A process produces a substantially stable aqueous dispersion of metal or metal oxide particles suitable for use in forming a transparent conductive coating. The process comprises the steps of (a) adding a nanocrystalline material to water, the nanocrystalline material comprising primary particles of metal or metal oxide having a substantially spherical shape and (b) mixing the nanocrystalline material and water to form an aqueous dispersion. The process identified above, prepares a substantially stable aqueous dispersion of nanocrystalline particles, which may be used in forming a transparent conductive coating.

Compositions for forming transparent conductive nanoparticle coatings and process of preparation therefor

A coated ceramic powder comprises a plurality of ceramic particles and a siloxane star-graft coating polymer encapsulating at least a portion of the particles. The coating polymer comprises Si(w,x,y,z), where w, x, y and z are the mole percent tetrafunctional, trifunctional, difunctional and monofunctional monomeric units, respectively, and wherein w is about 20-100 and x, y and z are about 0-30, 0-50 and 0-10, respectively, and at least one of x, y and z is greater than zero. A method of preparing a coated ceramic powder comprises the steps of (a) polymerizing a tetrafunctional siloxane monomer and at least one of a trifunctional siloxane monomer, a difunctional siloxane monomer and a monofunctional siloxane monomer, (b) adding a quantity of ceramic powder to a reaction vessel, (c) shear mixing the ceramic powder for a time sufficient to wet substantially all of the powder surface, (d) adding the siloxane polymer prepared in step (a) to the reaction vessel containing the shear mixed ceramic powder, (e) shear mixing the shear mixed ceramic powder and the siloxane polymer for a time sufficient to form a siloxane polymer coated ceramic powder, and (f) separating the coated ceramic powder from the components remaining in the reaction vessel.

Ceramic powders coated with siloxane star-graft polymers

A coated ceramic powder comprises a plurality of ceramic particles and a siloxane star-graft coating polymer encapsulating at least a portion of the particles. The coating polymer comprises Si(w,x,y,z), where w, x, y and z are the mole percent tetrafunctional, trifunctional, difunctional and monofunctional monomeric units, respectively, and wherein w, x, y and z are about 45-75, 5-25, 5-45 and 5-10, respectively. A method of preparing a coated ceramic powder comprises the steps of (a) polymerizing each of a tetrafunctional siloxane monomer, a trifunctional siloxane monomer, a difunctional siloxane monomer, and a monofunctional siloxane monomer, (b) adding a quantity of ceramic powder to a reaction vessel, (c) shear mixing the ceramic powder for a time sufficient to wet substantially all of the powder surface, (d) adding the siloxane polymer prepared in step (a) to the reaction vessel containing the shear mixed ceramic powder, (e) shear mixing the shear mixed ceramic powder and the siloxane polymer for a time sufficient to form a siloxane polymer coated ceramic powder, and (f) separating the coated ceramic powder from the components remaining in the reaction vessel. The process may be rendered continuous by employing continuous high-shear mixing equipment and appropriate process modifications.

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John H Aikens