METHOD OF COATING HEAT TRANSFER COMPONENTS TO IMPART SUPERHYDROPHOBICITY

• US 20190330734A1
• Filed: 04/24/2019
• Published: 10/31/2019
• Est. Priority Date: 04/25/2018
• Status: Active Application

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Miljkovic, Nenad, Boyina, Kalyan S., Chavan, Shreyas
• Application Number:
  US16/393,048
• Publication Number:
  US 20190330734A1
• Time in Patent Office: Days
• CPC Class Codes: B05D 1/60 Deposition of organic layers from vapour phase vapour phase deposition in general C23C14/00, C23C16/00
• CPC Class Codes: B05D 2202/00 Metallic substrate
• CPC Class Codes: B05D 2202/10 based on Fe
• CPC Class Codes: B05D 2202/25 based on Al
• CPC Class Codes: B05D 2202/30 based on refractory metals (Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, W)
• CPC Class Codes: B05D 2202/35 based on Ti
• CPC Class Codes: B05D 2202/40 based on other transition elements
• CPC Class Codes: B05D 2202/45 based on Cu
• CPC Class Codes: B05D 2518/10 Silicon-containing polymers
• CPC Class Codes: B05D 3/102 Pretreatment of metallic substrates C23C takes precedence
• CPC Class Codes: 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
• CPC Class Codes: B05D 7/14 to metal, e.g. car bodies involving a chemical reaction between the metal and the coating C23
• CPC Class Codes: C23C 16/0227 by cleaning or etching
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 8/02 Pretreatment of the material to be coated C23C8/04 takes precedence
• CPC Class Codes: C23C 8/42 only one element being applied
• CPC Class Codes: C23C 8/80 After-treatment
• CPC Class Codes: F28F 17/005 Means for draining condensates from heat exchangers, e.g. from evaporators F28B9/08 takes precedence
• CPC Class Codes: F28F 2245/04 hydrophobic

Abstract

A method for coating heat transfer components to impart superhydrophobicity comprises conveying one or more heat transfer components to a cleaning station, where the one or more heat transfer components are cleaned with an organic solvent. After the cleaning, the one or more heat transfer components are conveyed to a nanostructuring station and immersed in hot water for surface oxidation and roughening. After the immersion in hot water, the one or more heat transfer components are conveyed to a functionalization station and exposed to a heated precursor vapor comprising a hydrophobic species. During the exposure, the hydrophobic species is deposited on roughened surfaces of the one or more heat transfer components, thereby forming a superhydrophobic coating. Prior to being conveyed to the cleaning station, the one or more heat transfer components may be attached to an automated conveyor system positioned to traverse the cleaning, nanostructuring, and functionalization stations.

Claims

1. A method of coating heat transfer components to impart superhydrophobicity, the method comprising:

conveying one or more heat transfer components to a cleaning station and cleaning the one or more heat transfer components with an organic solvent;

after the cleaning, conveying the one or more heat transfer components to a nanostructuring station and immersing the one or more heat transfer components in hot water for surface oxidation and roughening; and

after the immersion in hot water, conveying the one or more heat transfer components to a functionalization station and exposing the one or more heat transfer components to a heated precursor vapor comprising a hydrophobic species,

wherein, during the exposure, the hydrophobic species is deposited on roughened surfaces of the one or more heat transfer components, thereby forming a superhydrophobic coating.

2. The method of claim 1, further comprising, prior to conveying the one or more heat transfer components to the cleaning station, attaching the one or more heat transfer components to an automated conveyor system positioned to traverse the cleaning, nanostructuring, and functionalization stations.

3. The method of claim 1, wherein the cleaning station comprises a spray nozzle in fluid communication with the organic solvent, the cleaning comprising spraying the organic solvent onto the one or more heat transfer components, or

wherein the cleaning station comprises a vat containing the organic solvent, the cleaning comprising submerging the one or more heat transfer components in the organic solvent.

4. The method of claim 3, wherein the one or more heat transfer components are cleaned with more than one organic solvent, the cleaning station comprising more than one vat and/or an additional spray nozzle in fluid communication with a different organic solvent.

5. The method of claim 1, wherein the one or more heat transfer components are cleaned sequentially with acetone and ethanol.

6. The method of claim 1, further comprising rinsing the one or more heat transfer components with water after the cleaning.

7. The method of claim 1, wherein the nanostructuring station comprises a heated vat containing the hot water, the one or more heat transfer components being submerged in the hot water for surface oxidation and roughening.

8. The method of claim 7, wherein the heated vat comprises a stainless steel drum wrapped with heating tape connected to a temperature controller.

9. The method of claim 1, wherein the hot water comprises hot deionized water maintained at a temperature in a range from 85°

C. to 95°

C.

10. The method of claim 1, wherein the roughened surfaces comprise nanostructured surface protrusions comprising a metal hydroxide and/or a metal oxide.

11. The method of claim 10, wherein the nanostructured surface protrusions comprise a blade-like shape.

12. The method of claim 1, further comprising, prior to the immersion in hot water, conveying the one or more heat transfer components to a microstructuring station, and exposing the one or more heat transfer components to an acid solution.

13. The method of claim 1, wherein the exposure to the heated precursor vapor takes place in an enclosed chamber where the heated precursor vapor is maintained at a temperature in a range from about 80°

C. to about 100°

C.

14. The method of claim 13, wherein the enclosed chamber comprises a stainless steel drum with a lid, the stainless steel drum being wrapped with heating tape connected to a temperature controller.

15. The method of claim 1, wherein the heated precursor vapor comprises a silane and toluene, the silane being the hydrophobic species.

16. The method of claim 1, wherein the one or more heat transfer components are fully-assembled heat exchangers.

17. The method of claim 1, wherein, individually, the one or more heat transfer components have a length exceeding 25 cm.

18. The method of claim 17, wherein the length exceeds 50 cm.

19. The method of claim 1, wherein the one or more heat transfer components comprise one or more metals selected from the group consisting of:

aluminum, titanium, iron, chromium, nickel, molybdenum, and copper.

20. The method of claim 1, further comprising, prior to conveying the one or more heat transfer components to the cleaning station, attaching the one or more heat transfer components to an automated conveyor system positioned to traverse the cleaning, nanostructuring, and functionalization stations,

wherein the one or more heat transfer components are cleaned sequentially with acetone and ethanol, and further comprising rinsing the one or more heat transfer components with water after the cleaning,

wherein the nanostructuring station comprises a heated vat containing the hot water, the one or more heat transfer components being submerged in the hot water for surface oxidation and roughening, the hot water comprising hot deionized water maintained at a temperature in a range from 85°

C. to 95°

C.,

further comprising, prior to the submersion in hot water, conveying the one or more heat transfer components to a microstructuring station, and exposing the one or more heat transfer components to an acid solution, and

wherein the exposure to the heated precursor vapor takes place in an enclosed chamber where the heated precursor vapor is maintained at a temperature in a range from about 80°

C. to about 100°

C.