CN110267493B - Flexible ultrathin liquid absorption core with hierarchical porous structure and manufacturing method thereof - Google Patents

Abstract

The invention relates to a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure, which includes a first-level porous skeleton structure and a second-level micro-nano porous structure; the first-level porous skeleton structure is a flexible layer with first-level pores evenly distributed, and the first-level porous skeleton The thickness of the structure and the size of the primary pores are both on the millimeter level; the secondary micro-nano porous structure is evenly distributed with secondary pores, the thickness of the secondary micro-nano porous structure is on the nano level, and the size of the secondary pores is on the micron level, or partially The size of the secondary pores is on the micron scale, and some of the secondary pores are on the nanoscale; the secondary micro-nano porous structure is attached to the surface of the primary porous skeleton structure; it also includes tertiary nanostructures, which are attached to the primary porous skeleton structure. Porous skeleton structure and secondary micro-nano porous structure on the surface. It also relates to a method for manufacturing a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure. The invention can simultaneously meet the heat dissipation requirements of ultra-thinness, flexibility and strong capillary performance, and belongs to the technical field of ultra-thin heat pipes.

Description

A flexible ultra-thin liquid-absorbent core with hierarchical porous structure and manufacturing method thereof

Technical field

The invention relates to the technical field of ultra-thin heat pipes, and in particular to a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure and a manufacturing method thereof.

Background technique

In recent years, with the rapid development of smart phones, smart watches and other microelectronic devices, their heating power has increased day by day, while the effective heat dissipation volume has gradually decreased, and the heat dissipation problem of electronic chips has become increasingly serious. Ultra-thin heat pipes have extremely high thermal conductivity and ultra-thin thickness, making them an ideal solution to solve the heat dissipation problem of microelectronic devices. As the core component of the ultra-thin heat pipe, the liquid-absorbing wick determines the heat transfer performance of the ultra-thin heat pipe. Most of the liquid absorbing cores of existing ultra-thin heat pipes adopt micro-groove structures or wire mesh structures, which have poor capillary performance and are difficult to meet the growing heat dissipation needs. In addition, the development of flexible microelectronic devices requires heat dissipation devices to also have good flexibility.

There is no liquid-absorbent core with both good flexibility and good capillary properties in the prior art.

Contents of the invention

In view of the technical problems existing in the prior art, the purpose of the present invention is to provide a flexible ultra-thin liquid-absorbent core with a graded porous structure that has both good flexibility and good capillary performance; Method of manufacturing thin absorbent wick.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A flexible ultra-thin liquid-absorbent core with a hierarchical porous structure, including a first-level porous skeleton structure and a second-level micro-nano porous structure; the first-level porous skeleton structure is a flexible layer with evenly distributed first-level pores, and the thickness of the first-level porous skeleton structure and the size of the primary pores are all millimeter-scale; the secondary micro-nano-porous structure is evenly distributed with secondary pores, the thickness of the secondary micro-nano-porous structure is nanoscale, the size of the secondary pores is micron-scale, or some of the secondary pores The size of the secondary pores is on the micron scale, and the size of some of the secondary pores is on the nanoscale; the secondary micro-nano porous structure is attached to the surface of the primary porous skeleton structure. The surface mentioned here includes the surface within the primary pores of the primary porous skeleton structure and the surface outside the primary pores.

As a preference, a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure also includes a tertiary nanostructure; the tertiary nanostructure is evenly distributed with tertiary pores, and the size of the tertiary pores is nanoscale; the tertiary nanostructure Attached to the surface of the primary porous skeleton structure and the secondary micro-nano porous structure. The surface here refers to the surface within the first-level pores and the surface outside the first-level pores containing the first-level porous skeleton structure, and the surface within the second-level pores and the surface outside the second-level pores containing the second-level micro-nano porous structure.

As a preference, the primary porous skeleton structure is mesh-like, which is a metal mesh or a metal fiber sintered felt.

As a preference, the secondary micro-nano porous structure is only attached to the inner surface of the primary pores.

As a preference, the primary porous skeleton structure is a crisscross network structure.

Preferably, a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure further includes a groove extending longitudinally or transversely through the liquid-absorbent core.

As a preference, the diameter of the metal wire or metal fiber is 0.2-0.5mm, and the distance between two adjacent parallel metal wires or metal fibers is 1-3mm; the distance between the two ends of the groove and the edge of the primary porous skeleton structure is 5-10mm; the thickness of the first-level porous skeleton structure is 0.05-0.15mm.

A method for manufacturing a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure, which is characterized by: including the following steps: a. Making a network-like primary porous skeleton structure; b. The secondary micro-nano porous structure is deposited through electrochemical deposition, The solid-phase sintering or physical sputtering process is attached to the inner surface of the first-level pores of the first-level porous skeleton structure, and the first-level porous skeleton structure and the second-level micro-nano porous structure are fixed together through the sintering process; c. Using physical spraying, After the chemical etching or chemical vapor deposition process, the third-level nanostructure is produced through the sintering process, which is simultaneously attached to the surface of the primary porous skeleton structure and the secondary micro-nano porous structure.

Preferably, after step c, the liquid-absorbing wick structure is removed by laser processing to form a groove.

As a preference, the sintering process of steps b and c is completed in steps, or is completed in one step in step c; a reduction treatment is performed after step c.

The principle of the invention is: using a first-level porous skeleton structure as the matrix, which has good flexibility and mechanical properties; using a second-level micro-nano porous structure and a third-level nanostructure to enhance the capillary properties and mechanical properties of the matrix. Through the composite metal mesh skeleton and micro-nano porous structure, it can simultaneously meet the heat dissipation requirements of ultra-thinness, flexibility and strong capillary performance.

The invention has the following advantages:

(1) By growing micro-nano porous structures in the primary porous skeleton structure matrix, it not only enhances the capillary properties of the metal mesh and metal fiber sintered felt, but also keeps the flexibility and thickness of the porous matrix basically unchanged, making it a flexible and ultra-thin A good choice for wicks in heat dissipation devices.

(2) The core of the present invention is to grow smaller-scale micro-nano composite structures on a primary porous skeleton structure matrix. Different micro-nano composite structures and liquid-absorbent core levels can be selected according to the different matrix materials and the needs of practical applications. numbers and has good applicability.

(3) The present invention has simple manufacturing process, low cost, good flexibility and capillary performance, and can meet the use requirements of ultra-thin and flexible heat dissipation devices.

(4) The secondary micro-nano porous structure is only attached to the inner surface of the primary pores and does not increase the thickness of the primary porous skeleton structure.

(5) The groove structure can increase the permeability of the liquid working medium backflow and improve the performance of the liquid-absorbing core.

Description of the drawings

Figure 1 is a schematic structural diagram of a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure according to Embodiment 1.

Figure 2 is a schematic structural diagram of a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure according to the second embodiment.

Figure 3 is a schematic structural diagram of a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure according to Embodiment 3.

Among them, 1 is the first-level porous skeleton structure, 2 is the second-level micro-nano porous structure, 3 is the third-level nanostructure, 4 is the groove, 11 is the first-level pore, and 21 is the second-level pore.

Detailed ways

The present invention will be described in further detail below in conjunction with specific embodiments.

Embodiment 1

A flexible ultra-thin liquid-absorbent core with a hierarchical porous structure, including a first-level porous skeleton structure, a second-level micro-nano porous structure, and a third-level nanostructure.

The primary porous skeleton structure is a 300-mesh copper wire mesh structure, including primary pores formed between copper wires. The diameter of the copper wire is 0.05mm, and the overall thickness of the copper wire mesh is about 0.08mm.

The secondary micro-nano porous structure is attached to the inner surface of the primary pores through galvanostatic electrodeposition, including micro-nano-scale copper particles and irregular secondary pores formed by adjacent copper particles. The galvanostatic electrodeposition method of this embodiment uses a two-electrode system, with a copper mesh as the cathode and another copper sheet as the anode. The distance between the two electrodes is 10mm. The electrolyte uses 0.4M copper sulfate and 1.5M sulfuric acid. The current density is 1A/cm ² and the electrodeposition time is 40s.

After the electrodeposition is completed, the sample is cleaned and then placed in a muffle furnace for sintering process. The sintering temperature is 350°C and kept in an air environment for 1 hour. The sintering process can not only combine the first-level porous skeleton structure and the second-level microstructure. A strong sintered diameter is formed between the nanoporous structures, and a third-level nanostructure (third-level copper oxide nanowire structure) can be formed on the surface of the first-level porous skeleton structure and the second-level micro-nano-porous structure; finally, the liquid-absorbent core is reduced A hydrogen atmosphere is used for treatment and reduction. The liquid-absorbent core is heated to 300°C in a hydrogen atmosphere and kept warm for 1 hour. After cooling in the furnace, the final flexible ultra-thin liquid-absorbent core with a three-level porous structure is obtained.

Embodiment 2

This embodiment adds a trench structure based on Embodiment 1.

The liquid-absorbing core structure with a width of 0.3mm is removed by laser processing on the surface of the liquid-absorbing core to form parallel transverse grooves. The spacing between parallel grooves is 1.5mm; the grooves can increase the amount of liquid working fluid. The permeability of backflow improves the performance of the absorbent core.

The parts not mentioned in this embodiment are the same as those in Embodiment 1.

Embodiment 3

This embodiment is a flexible ultra-thin liquid-absorbent core with a hierarchical porous structure, including a primary porous skeleton structure and a secondary micro-nano porous structure.

The primary porous skeleton structure and secondary micro-nano porous structure are the same as those in Embodiment 1.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, etc. may be made without departing from the spirit and principles of the present invention. All simplifications should be equivalent substitutions, and are all included in the protection scope of the present invention.

Claims (3)

1. A method of making a flexible ultrathin wick having a hierarchical porous structure, comprising: the flexible ultrathin liquid absorption core comprises a primary porous framework structure and a secondary micro-nano porous structure; the primary porous framework structure is a flexible layer, primary pores are uniformly distributed, and the thickness of the primary porous framework structure and the size of the primary pores are millimeter-sized; the secondary micro-nano porous structure is uniformly distributed with secondary pores, the thickness of the secondary micro-nano porous structure is nano-scale, the size of the secondary pores is micro-scale, or the size of part of the secondary pores is micro-scale, and the size of part of the secondary pores is nano-scale; the secondary micro-nano porous structure is attached to the surface of the primary porous framework structure;

the flexible ultrathin liquid absorption core also comprises a three-level nano structure; three-level pores are uniformly distributed in the three-level nano structure, and the size of the three-level pores is nano-level; the three-level nano structure is attached to the surfaces of the first-level porous framework structure and the second-level micro-nano porous structure;

the primary porous framework structure is a crisscross net structure and is a metal wire mesh or a metal fiber sintered felt;

the secondary micro-nano porous structure is only attached to the inner surface of the primary pore;

the flexible ultrathin liquid absorption core further comprises a groove which extends longitudinally or transversely and penetrates through the liquid absorption core;

a method of making a flexible ultrathin wick comprising the steps of:

a. manufacturing a net-shaped primary porous framework structure;

b. the secondary micro-nano porous structure is attached to the inner surface of a primary pore of the primary porous skeleton structure through electrochemical deposition, solid-phase sintering or physical sputtering process, and the primary porous skeleton structure and the secondary micro-nano porous structure are fixed together through the sintering process;

c. after adopting physical spraying, chemical corrosion or chemical vapor deposition process, manufacturing a three-level nano structure through a sintering process, attaching the three-level nano structure to the surfaces of the first-level porous skeleton structure and the second-level micro-nano porous structure during manufacturing, and removing the liquid absorption core structure through a laser processing method to form a groove after the step c.

2. A method of making a flexible ultrathin liquid absorbent core having a hierarchical porous structure according to claim 1 wherein: the diameter of the metal wires or the metal fibers is 0.2-0.5mm, and the distance between two adjacent parallel metal wires or metal fibers is 1-3mm; the distance between two ends of the groove and the edge of the primary porous framework structure is 5-10mm; the thickness of the primary porous skeleton structure is 0.05-0.15mm.

3. A method of making a flexible ultrathin liquid absorbent core having a hierarchical porous structure according to claim 1 wherein: the sintering process of the step b and the step c is finished in steps or is finished by combining in the step c once; and c, performing reduction treatment.