# US 10,501,840 B2 · Influence on surface interactions by substructure topography > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,840 B2 - Document ID: US10501840B2 - Status: Granted - Kind: B2 - Application number: 15/638,513 - Filed: 2017-06-30 - Published: 2018-01-04 - Granted: 2019-12-10 - Earliest claimed: 2016-07-01 - Assignees: United States of America as represented by the Administer of NASA - Applicants: U.S.A. as represented by the Administrator of the National Aeronautics and Space Administration - Inventors: Christopher J. Wohl, Jr.; Frank L. Palmieri - Web page: https://patentgrep.com/patent/US10501840B2 ## CPC - C23C 14/028: {Physical treatment to alter the texture of the substrate surface, e.g. grinding, polishing} - B23K 26/3584: {Increasing rugosity, i.e. roughening} - C23C 14/58: After-treatment - F01D 5/288: {Protective coatings for blades} - B05D 3/12: by mechanical means - 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 2202/25: based on Al - B05D 2504/00: Epoxy polymers - B64C 3/26: Construction, shape, or attachment of separate skins, e.g. panels - B64D 15/00: De-icing or preventing icing on exterior surfaces of aircraft - 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) - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - B64C: AEROPLANES; HELICOPTERS - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT ## Abstract A method of forming a smooth aerodynamic surface that permits laminar flow of air over the smooth aerodynamic surface. Selected portions of a surface of a substrate material are ablated utilizing a laser to form a treated substrate surface having a predefined roughness. The treated substrate surface is coated to form a solid layer of material having a smooth aerodynamic surface that promotes laminar flow. The solid layer of material has a lower modulus of elasticity than the substrate material to provide durotaxis when an insect impacts the solid layer of epoxy material to thereby reduce adhesion of insect residue or other matter to the smooth aerodynamic surface. ## Claims ### Claim 1 A method of forming a smooth aerodynamic surface, wherein the resulting smooth aerodynamic surface prevents disruption of laminar flow of air over the smooth aerodynamic surface, the method comprising: ablating selected portions of a surface of a substrate material utilizing a laser to form a treated substrate surface having a roughness of about 1.0 micrometer to about 3.0 micrometers to promote abhesion; coating the treated substrate surface with a coating material; curing the coating material to form a solid layer of the coating material on the treated substrate surface, the solid layer of the coating material having a smooth aerodynamic surface that promotes laminar flow of air over the smooth aerodynamic surface, and a thickness of about 1.0 micrometers to about 100 micrometers; and wherein: the solid layer of the coating material has a lower modulus of elasticity than the substrate material, and the roughness of the substrate, combine to provide a durotaxis effect when an insect impacts and deforms the solid layer of the coating material to thereby reduce adhesion of insect residue on the smooth aerodynamic surface of the coating material. ### Claim 2 (depends on 1) The method of claim 1, wherein: the coating material comprises epoxy that forms a solid layer of epoxy when cured. ### Claim 3 (depends on 2) The method of claim 2, wherein: the smooth aerodynamic surface of the solid layer of epoxy has a roughness of less than about 0.5 micrometers. ### Claim 4 (depends on 2) The method of claim 2, wherein: the solid layer of epoxy has a thickness of about 1.0 to about 3.0 micrometers. ### Claim 5 (depends on 1) The method of claim 1, wherein: the solid layer of the coating material has a modulus of elasticity that is at least about an order of magnitude less than a modulus of elasticity of the substrate material. ### Claim 6 (depends on 1) The method of claim 1, wherein: the solid layer of the coating material has a modulus of elasticity in a range of about 4,000 psi to about 435,000 psi. ### Claim 7 (depends on 1) The method of claim 1, wherein: the smooth aerodynamic surface has a roughness of less than about 20 micro-inches. ### Claim 8 (depends on 1) The method of claim 1, wherein: the substrate material comprises an aluminum alloy. ### Claim 9 (depends on 1) The method of claim 1, wherein: the substrate material comprises a composite material having reinforcing fibers embedded in a polymer matrix. ### Claim 10 (depends on 1) The method of claim 1, including: utilizing the smooth aerodynamic surface to form at least a portion of an airfoil. ### Claim 11 (depends on 1) The method of claim 1, wherein: the coating material has a viscosity of about 5 to about 100000 cp. ### Claim 12 (depends on 1) The method of claim 1, wherein: the laser ablates the substrate surface in a manner that causes the treated substrate surface to include a plurality of parallel grooves that are spaced apart about 25 micrometers, wherein the parallel grooves are about 5 micrometers to about 75 micrometers wide, and have a depth of about 0.1 micrometers to about 40 micrometers. ### Claim 13 (depends on 12) The method of claim 12, including: aligning the parallel grooves based on a direction of airflow over the smooth aerodynamic surface. ### Claim 14 (depends on 1) The method of claim 1, wherein: the laser ablates the substrate surface in a manner that causes the treated substrate surface to have a plurality of grooves that crisscross. ### Claim 15 (depends on 1) The method of claim 1, wherein: the coating material comprises fluorinated alkyl ether epoxy resin. ### Claim 16 A method of forming a smooth aerodynamic surface that permits laminar flow of air over the smooth aerodynamic surface, the method comprising: providing a material forming a substrate, the material having a first modulus of elasticity; ablating selected portions of a surface of a substrate utilizing a laser to form a treated substrate surface having a predefined roughness of about 1.0 micrometer to about 3.0 micrometers to promote abhesion; coating the treated substrate surface with an uncured coating material; curing the coating material to form a solid layer of coating material on the treated substrate surface; and wherein: the solid layer of coating material has a second Modulus of elasticity that is at least about an order of magnitude less than the first modulus of elasticity, and the roughness of the substrate, combine to provide durotaxis for deformation of the solid layer of coating material to reduce adhesion of insect residue on the solid layer of coating material due to the lower modulus of elasticity of the solid layer of coating material. ### Claim 17 (depends on 16) The .method of claim 16, wherein: the solid layer of coating material comprises an epoxy material having a thickness of about 1.0 to about 100.0 micrometers. ### Claim 18 A method of forming an aerodynamic surface that permits laminar flow of air over the aerodynamic surface, the method comprising: ablating selected portions of a surface of a substrate material utilizing a laser to form a treated substrate surface having a predefined roughness selected to promote abhesion; coating the treated substrate surface with a coating material having a modulus of elasticity that is at least about one order of magnitude less than a modulus of the substrate material; curing the coating material to form a solid layer of the coating material having a smooth aerodynamic surface that permits laminar flow of air over the aerodynamic surface; and wherein: the solid layer of the coating material reduces adhesion of inset residue due to durotaxis provided by the combination of the treated substrate surface having a predefined roughness and the greater elasticity of the coating material relative to the substrate material, the solid layer of coating material deforms in response to an impact of an insect, and the solid layer of the coating material has a thickness above the surface of the substrate material of about 1.0 micrometers. ### Claim 19 (depends on 18) The method of claim 18, wherein: the predefined roughness is about 1.0 micrometers to about 300 micrometers.