Self-driven water collecting surface with superhydrophobic-superhydrophilic structure and method for preparing the same

Patent metadata

Field	Value
Publication number	US-11878372-B2
Application number	US-201817052524-A
Country	US
Kind code	B2
Filing date	Nov 14, 2018
Priority date	Jun 28, 2018
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

The present disclosure provides a self-driven water collecting surface having a superhydrophilic-superhydrophobic structure, and a method for preparing the same, belonged to the technical field of water harvesting and superhydrophobic surfaces. The water collecting surface is a superhydrophobic surface with the distributed superhydrophilic region. The superhydrophilic region is a venation channel network structure consisting of hierarchical superhydrophilic channels. In the method, a pulsed laser is firstly adopted to form periodically distributed peak-pit microstructures and nanostructures, which is then modified with a low-surface-energy substance. Then, the low-surface-energy substance layer is removed by a pulsed laser again according to a venation channel network pattern. The laser scanned region is superhydrophilic, while the other regions are superhydrophobic. So that, the self-driven water collecting surface with the superhydrophobic-superhydrophilic structure is obtained.

First claim

What is claimed is:

1. A self-driven water collecting surface having a superhydrophilic-superhydrophobic structure, wherein the water collecting surface comprises a superhydrophilic region and a superhydrophobic region, and the superhydrophobic region is a superhydrophobic surface, the superhydrophilic region is a venation channel network structure comprising superhydrophilic channels of different orders connected to each other;
the superhydrophilic-superhydrophobic structure comprises:
periodically distributed peak-pit microstructures comprising alternately distributed micro-peaks and micro-pits, and
nanostructures distributed on the peak-pit microstructures;
wherein in the superhydrophobic surface, the superhydrophilic-superhydrophobic structure further comprises a superhydrophobic substance located on the peak-pit microstructures.

2. The self-driven water collecting surface of claim 1 , wherein a total number of the orders is from two to five.

3. The self-driven water collecting surface of claim 2 , wherein the total number of the orders is four, the superhydrophilic channels of different orders are:
a first-order channel located at a center of the water collecting surface;
second-order channels extended from both sides of the first-order channel, each of the second-order channels comprising a wider end and a narrower end, the wider end of the each of the second-order channels being connected to the first-order channel;
third-order channels extended from both sides of the each of the second-order channels; and
fourth-order channels extend from both sides of the each of the third-order channels.

4. The self-driven water collecting surface of claim 1 , wherein the superhydrophilic channels are primary channels and secondary channels, the secondary channels are configured for collecting water from the superhydrophobic surface and transporting the water to the primary channels, the primary channels are configured for directional transporting the water to a designated location.

5. The self-driven water collecting surface of claim 4 , wherein a total number of the orders is five, the superhydrophilic channels of different orders are a first-order channel, second-order channels, third-order channels, fourth-order channels, and fifth-order channels; the first-order channel and the second-order channels are the primary channels; the third-order channels, the fourth-order channels, and the fifth-order channels are the secondary channels.

6. The self-driven water collecting surface of claim 5 , wherein each of the primary channels is a wedge-shaped structure with an included angle of 2° to 30° and a length of about 0.5 cm to about 20 cm, and a width of the second-order channels is smaller than a width of the first-order channel.

7. The self-driven water collecting surface of claim 6 , wherein each of the secondary channels is a constant width channel with a width less than a maximum width of the second-order channels, the secondary channels at different orders have different widths, the higher the order, the smaller the width of the secondary channels.

8. The self-driven water collecting surface of claim 4 , wherein the secondary channels are intercrossed with each other to constitute a network, and are distributed around the primary channels.

9. A preparing method of the self-driven water collecting surface of claim 1 , comprising following steps:
ablating a metal surface by a first pulsed laser to form periodically distributed peak-pit microstructures comprising alternately distributed micro-peaks and micro-pits, and to form nanostructures distributed on the peak-pit microstructures;
modifying the metal surface ablated by the first pulsed laser with a low-surface-energy substance to form the metal surface into a superhydrophobic surface;
drawing a venation channel network pattern using computer drawing software;
scanning the superhydrophobic surface by a second pulsed laser according to the venation channel network pattern to remove the low-surface-energy substance in a laser scanned region of the superhydrophobic surface without destroying the peak-pit microstructures and the nanostructures, thereby converting the laser scanned region of the superhydrophobic surface from superhydrophobic to superhydrophilic, while other regions of the superhydrophobic surface are still superhydrophobic.

10. The method of claim 9 , wherein each of the first pulsed laser and the second pulsed laser is a nanosecond laser, a picosecond laser, or a femtosecond laser.

11. The method of claim 9 , wherein the modifying is liquid-phase modifying, comprising:
formulating a dilute solution of lauric acid or 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane in methanol or ethanol in a mass concentration of about 0.1% to about 5%;
immersing the metal surface ablated by the first pulsed laser in the dilute solution for about 1 hour to about 2 hours; and
drying the metal surface by heating in a drying oven at about 80° C. to about 100° C.

12. The method of claim 9 , wherein the modifying is gas-phase modifying, comprising:
heating the metal surface ablated by the first pulsed laser together with about 0.5 g to about g of 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane in a drying oven at about 80° C. to about 100° C. for about 0.5 hours to about 2 hours.

13. The self-driven water collecting surface of claim 8 , wherein spacing between adjacent secondary channels is about 0.05 mm to about 10 mm.

14. The self-driven water collecting surface of claim 1 , wherein each of the micro-peaks has a diameter of about 20 microns to about 120 microns and a height of about 20 microns to about 160 microns, and spacing between adjacent micro-peaks is about 20 microns to about 120 microns.

15. The self-driven water collecting surface of claim 1 , wherein each of the micro-pits has a diameter of about 20 microns to about 120 microns and a depth of about 10 microns to about 50 microns, and spacing between adjacent micro-pits is about 20 microns to about 120 microns.

16. The self-driven water collecting surface of claim 1 , wherein the nanostructures are nanoparticles or nanovilli.

17. The self-driven water collecting surface of claim 16 , wherein a size of each of the nanoparticles and the nanovilli is smaller than 800 nanometers.

18. The self-driven water collecting surface of claim 1 , wherein the superhydrophobic substance is selected from the group consisting of lauric acid, 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane, and a combination thereof.

19. A self-driven water collecting surface having a superhydrophilic-superhydrophobic structure, wherein the water collecting surface comprises a superhydrophilic region and a superhydrophobic region, and the superhydrophobic region is a superhydrophobic surface, the superhydrophilic region is a venation channel network structure comprising superhydrophilic channels of different orders connected to each other;
the superhydrophilic channels are primary channels and secondary channels, the secondary channels are configured for collecting water from the superhydrophobic surface and transporting the water to the primary channels, the primary channels are configured for directional transporting the water to a designated location;
a total number of the orders is five, the superhydrophilic channels of different orders are a first-order channel, second-order channels, third-order channels, fourth-order channels, and fifth-order channels; the first-order channel and the second-order channels are the primary channels; the third-order channels, t

Assignees

• Univ Tsinghua

Inventors

• Zhong Min-Lin
• Zhang hong-jun
• Liu wei-jian

Classifications

• B23K26/361 Primary

  for deburring or mechanical trimming (B23K26/351 takes precedence) · CPC title

• B05D5/08 Primary

  to obtain an anti-friction or anti-adhesive surface (rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30) · CPC title

• B23K26/352

  for surface treatment · CPC title

• B23K26/0624

  using ultrashort pulses, i.e. pulses of 1 ns or less · CPC title

• B23K26/082

  Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head · CPC title