# US 11,441,852 B2 · Droplet ejecting coatings > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,852 B2 - Document ID: US11441852B2 - Status: Granted - Kind: B2 - Application number: 17/530,278 - Filed: 2021-11-18 - Published: 2022-03-10 - Granted: 2022-09-13 - Earliest claimed: 2016-09-19 - Assignees: Nelumbo Inc. - Applicants: Nelumbo Inc. - Inventors: Lance R. Brockway; David C. Walther - Web page: https://patentgrep.com/patent/US11441852B2 ## CPC - F28F 13/187: {especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites} - B05D 1/18: performed by dipping - B05D 1/38: with intermediate treatment (intermediate treatment per se B05D3/00) - B05D 3/065: {After-treatment} - B05D 3/102: {Pretreatment of metallic substrates (C23C takes precedence)} - B05D 3/12: by mechanical means - B05D 5/02: to obtain a matt or rough surface - B05D 5/08: to obtain an anti-friction or anti-adhesive surface (rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30) - B05D 7/14: to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23) - B05D 7/50: {Multilayers} - B05D 7/52: {Two layers} - C03C 17/25: by deposition from the liquid phase - C03C 17/42: at least one coating of an organic material and at least one non-metal coating - B05D 2202/25: based on Al - B05D 2350/63: ceramic layer - B05D 2401/20: Aqueous dispersion or solution - B05D 2506/10: Fluorinated polymers - B05D 2506/15: Polytetrafluoroethylene [PTFE] - B05D 2518/10: Silicon-containing polymers - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - B82Y 40/00: Manufacture or treatment of nanostructures - C03C 2217/75: Hydrophilic and oleophilic coatings - C23C 18/1216: {Metal oxides (C23C18/1212 takes precedence)} - C23C 18/1241: {Metallic substrates} - C23C 18/1254: {Sol or sol-gel processing} - C23C 18/1283: {Control of temperature, e.g. gradual temperature increase, modulation of temperature} - F28F 2245/02: hydrophilic - F28F 2245/04: hydrophobic - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract Coating compositions are provided that eject droplets of condensed fluid from a surface. The coatings include a nanostructured coating layer and in some embodiments, also include a hydrophobic layer deposited thereon. The coating materials eject droplets from the surface in the presence of non-condensing gases such as air and may be deployed under conditions of supersaturation of the condensed fluid to be ejected. A heat exchanger design utilizing the coating is described herein. ## Claims ### Claim 1 A heat exchanger that comprises coated surfaces, wherein the coated surfaces comprise a nanostructured coating material deposited on regions of a metal surface of the heat exchanger and a hydrophobic functional layer coated over the nanostructured coating material, wherein when the heat exchanger is in operation and is exposed to a process fluid under conditions in which condensation of at least a portion of condensable components in the process fluid occurs, droplets of a condensate from the condensable components are formed on the coated surfaces and the coated surfaces eject the droplets, and wherein the nanostructured coating material comprises a metal oxide that is deposited onto the metal surface of the heat exchanger without the introduction of an electric current. ### Claim 2 (depends on 1) A heat exchanger according to claim 1, wherein the nanostructured coating material and the metal surface of the heat exchanger comprise different metals. ### Claim 3 (depends on 1) A heat exchanger according to claim 1, further comprising one or more hydrophilic surface(s), wherein at least one hydrophilic surface is adjacent to at least one coated surface, wherein the adjacent coated surface is hydrophobic, and wherein when the heat exchanger is in operation, at least a portion of the droplets that are formed on the hydrophobic coated surface transfer to and traverse the hydrophilic surface as a liquid condensate. ### Claim 4 (depends on 3) A heat exchanger according to claim 3, wherein the liquid condensate is collected by a downstream condensate collector. ### Claim 5 (depends on 3) A heat exchanger according to claim 3, wherein the hydrophilic surface(s) comprise a nanostructured material. ### Claim 6 (depends on 1) A heat exchanger according to claim 1, wherein the droplets are ejected in the presence of one or more non-condensing gas. ### Claim 7 (depends on 1) A heat exchanger according to claim 1, wherein the droplets are ejected at supersaturation of the condensate above about 1.1. ### Claim 8 (depends on 1) A heat exchanger according to claim 1, wherein the droplets are ejected at an arithmetic mean droplet diameter less than about 500 micrometers. ### Claim 9 (depends on 1) A heat exchanger according to claim 1, wherein when the heat exchanger is in operation, frost formation on the heat exchanger is reduced or eliminated in comparison with a heat exchanger that does not comprise the coated surfaces. ### Claim 10 (depends on 1) A heat exchanger according to claim 1, wherein the metal oxide of the nanostructured coating material comprises a transition metal oxide, tin (IV) oxide, magnesium (II) oxide, aluminum oxide, or an earth metal oxide. ### Claim 11 (depends on 1) A heat exchanger according to claim 1, wherein the nanostructured coating material comprises zinc oxide, magnesium (II) oxide (MgO), iron (II, III) oxide (Fe3O4), iron (III) oxide (Fe2O3), manganese (IV) oxide (MnO2), manganese (II, III) oxide (Mn3O4), manganese (III) oxide (Mn2O3), nickel (II) oxide (NiO), nickel (III) oxide (Ni2O3) chromium (III) oxide (Cr2O3), copper (II) oxide (CuO), cobalt (II) oxide (CoO), cobalt (III) oxide (Co2O3), or cobalt (II, III) oxide (Co3O4). ### Claim 12 (depends on 1) A heat exchanger according to claim 1, wherein the hydrophobic functional layer comprises one or more hydrophobic functionality selected from alkyl, vinyl, phenyl, and fluoroalkyl. ### Claim 13 (depends on 12) A heat exchanger according to claim 12, wherein the hydrophobic functional layer comprises alkylsilane, vinylsilane, phenylsilane, or fluoroalkylsilane. ### Claim 14 (depends on 1) A heat exchanger according to claim 1, wherein the nanostructured coating material is immobilized on the metal surface of the heat exchanger by heat treatment at a temperature from 100° C. to 600° C. ### Claim 15 (depends on 1) A heat exchanger according to claim 1, wherein the nanostructured coating material is deposited onto the metal surface of the heat exchanger in a solution comprising: an alkaline earth metal or a transition metal salt; and hexamine. ### Claim 16 (depends on 1) A heat exchanger according to claim 1, wherein the metal surface of the heat exchanger comprises aluminum and the nanostructured coating material comprises zinc and/or manganese. ### Claim 17 (depends on 1) A heat exchanger according to claim 1, wherein retention of the condensate on the heat exchanger surface is prevented when the temperature of the surface of the heat exchanger is below the dew point of the condensable components of the process fluid. ### Claim 18 (depends on 1) A heat exchanger according to claim 1, wherein formation of adhered frost or ice on the coated surfaces is prevented when the temperature of the coated surfaces is below the freezing point of the condensable components of the process fluid. ### Claim 19 A heat exchanger that comprises coated surfaces, wherein the coated surfaces comprise a nanostructured coating material deposited on regions of a metal surface of the heat exchanger and a hydrophobic functional layer coated over the nanostructured coating material, wherein when the heat exchanger is in operation and is exposed to a process fluid under conditions in which condensation of at least a portion of condensable components in the process fluid occurs, droplets of a condensate from the condensable components are formed on the coated surfaces and the coated surfaces eject the droplets, further comprising one or more hydrophilic surface(s), wherein at least one hydrophilic surface is adjacent to at least one coated surface, wherein the adjacent coated surface is hydrophobic, and wherein when the heat exchanger is in operation, at least a portion of the droplets that are formed on the hydrophobic coated surface transfer to and traverse the hydrophilic surface as a liquid condensate. ### Claim 20 (depends on 19) A heat exchanger according to claim 19, wherein the liquid condensate is collected by a downstream condensate collector. ### Claim 21 (depends on 19) A heat exchanger according to claim 19, wherein the hydrophilic surface(s) comprise a nanostructured material. ### Claim 22 A heat exchanger that comprises coated surfaces, wherein the coated surfaces comprise a nanostructured coating material deposited on regions of a metal surface of the heat exchanger and a hydrophobic functional layer coated over the nanostructured coating material, wherein when the heat exchanger is in operation and is exposed to a process fluid under conditions in which condensation of at least a portion of condensable components in the process fluid occurs, droplets of a condensate from the condensable components are formed on the coated surfaces and the coated surfaces eject the droplets, and wherein the hydrophilic surface(s) comprise a nanostructured material. ### Claim 23 A heat exchanger that comprises coated surfaces, wherein the coated surfaces comprise a nanostructured coating material deposited on regions of a metal surface of the heat exchanger and a hydrophobic functional layer coated over the nanostructured coating material, wherein when the heat exchanger is in operation and is exposed to a process fluid under conditions in which condensation of at least a portion of condensable components in the process fluid occurs, droplets of a condensate from the condensable components are formed on the coated surfaces and the coated surfaces eject the droplets, and wherein the nanostructured coating material is deposited onto the metal surface of the heat exchanger in a solution comprising: an alkaline earth metal or a transition metal salt; and hexamine.