# US 11,078,593 B2 · Radiative cooling substrate and manufacturing method of the same

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- Number: US 11,078,593 B2
- Document ID: US11078593B2
- Status: Granted
- Kind: B2
- Application number: 16/282,747
- Filed: 2019-02-22
- Published: 2020-04-30
- Granted: 2021-08-03
- Earliest claimed: 2018-10-31
- Assignees: National Tsing Hua University
- Applicants: National Tsing Hua University
- Inventors: Yu-Bin Chen; Hung-Sheng Han
- Web page: https://patentgrep.com/patent/US11078593B2

## CPC

- C09D 5/00: Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced {(electrically insulating plastics, resins or waxes H01B3/30)}; Filling pastes
- C25D 13/06: with polymers {(not used, see C09D5/44)}
- C09D 5/44: for electrophoretic applications (processes for coating by electrophoresis C25D13/00)
- C25D 13/12: characterised by the article coated
- C25D 13/20: Pretreatment
- C25D 13/22: Servicing or operating {apparatus or multistep processes}
- F28F 13/18: by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
- F28F 2245/06: having particular radiating, reflecting or absorbing features, e.g. for improving heat transfer by radiation
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)

## Abstract

A radiative cooling substrate and a manufacturing method of the radiative cooling substrate are provided. The radiative cooling substrate includes a metallic substrate and a chitosan layer disposed on the metallic substrate with a thickness of 0.5 μm to 10 μm. The chitosan layer emits radiation within a waveband between 8 μm and 13 μm.

## Claims

### Claim 1

A manufacturing method of a radiative cooling substrate, comprising:
forming a metallic substrate by depositing an adhesive layer with a second thickness on a silicon substrate and depositing a metal layer on the adhesive layer in an evaporation process, wherein the adhesive layer comprises chromium or titanium, and the second thickness is 10 nm to 50 nm;
preparing a chitosan solution, the chitosan solution comprising chitosan and a solvent, wherein the solvent comprises water, C1-C4 alcohols, and an acid, and a pH-value of the chitosan solution is less than seven;
providing the metallic substrate into an electrophoresis cell loaded with the chitosan solution;
applying a voltage to the metallic substrate for a predetermined time period;
depositing a chitosan layer comprising the chitosan with a first thickness on the metallic substrate in an electrophoretic process; and
obtaining the radiative cooling substrate;
wherein the first thickness is a value from 0.5 μm to 10 μm.

### Claim 2 (depends on 1)

The method of claim 1, wherein a ratio of a weight of the chitosan and a volume of the solvent is 0.01 g: 1000 mL to 20 g: 1000 mL.

### Claim 3 (depends on 1)

The method of claim 1, wherein the C1-C4 alcohols comprise ethyl alcohol, and a volume ratio of the water and the ethyl alcohol is less than 2:8.

### Claim 4 (depends on 1)

The method of claim 1, wherein the acid comprises acetic acid or hydrochloric acid.

### Claim 5 (depends on 1)

The method of claim 1, wherein the voltage is less than 30 V.

### Claim 6 (depends on 1)

The method of claim 1, wherein the predetermined time period is less than five minutes.