阅读说明：本技术 一种基于激光活化选择性金属化的柔性液态金属图案及其制备方法 (Flexible liquid metal pattern based on laser activation selective metallization and preparation method thereof ) 是由 周涛 肖成超 于 2021-08-31 设计创作，主要内容包括：本发明提供了一种基于激光活化选择性金属化的柔性液态金属图案及其制备方法,属于柔性传感器领域。所述制备方法包括以下步骤：步骤1：制备聚合物/激光吸收剂柔性复合材料；步骤2：使用激光辐照聚合物/激光吸收剂柔性复合材料表面,在辐照区域形成活化的图案,然后在辐照区域镀覆金属,得到金属图案；步骤3：将聚合物/激光吸收剂柔性复合材料浸入酸性或碱性溶液中,在金属图案上涂覆液态金属,得到柔性液态金属图案。本发明的制备方法无需掩膜,生产灵活性好,操作简单,成本可控。利用本发明的方法制得的柔性液态金属图案柔性好,在弯曲和拉伸条件下具有优异的导电性能,自修复性和耐酸/碱腐蚀性优良,在柔性传感器领域应用前景良好。(The invention provides a flexible liquid metal pattern based on laser activation selective metallization and a preparation method thereof, and belongs to the field of flexible sensors. The preparation method comprises the following steps: step 1: preparing a polymer/laser absorber flexible composite material; step 2: irradiating the surface of the polymer/laser absorber flexible composite material by using laser, forming an activated pattern in an irradiation area, and then plating metal in the irradiation area to obtain a metal pattern; and step 3: and (3) immersing the polymer/laser absorber flexible composite material into an acidic or alkaline solution, and coating liquid metal on the metal pattern to obtain a flexible liquid metal pattern. The preparation method provided by the invention does not need a mask, and has the advantages of good production flexibility, simplicity in operation and controllable cost. The flexible liquid metal pattern prepared by the method has good flexibility, excellent conductivity under bending and stretching conditions, excellent self-repairing property and acid/alkali corrosion resistance, and good application prospect in the field of flexible sensors.)

1. A preparation method of a flexible liquid metal pattern is characterized by comprising the following steps: the preparation method comprises the following steps:

step 1: uniformly mixing the polymer and the laser absorbent, carrying out melt blending, extruding and granulating, and then forming the obtained granules to obtain the polymer/laser absorbent flexible composite material;

step 2: irradiating the surface of the polymer/laser absorber flexible composite material by using laser, forming an activated pattern in an irradiation area, and then plating metal in the irradiation area to obtain a metal pattern;

and step 3: and (3) immersing the polymer/laser absorbent flexible composite material treated in the step (2) into an acidic or alkaline solution, and coating liquid metal on the metal pattern to obtain a flexible liquid metal pattern.

2. The method of claim 1, wherein: in the step 1, the polymer is one or more than two of styrene elastomer, olefin elastomer, diene elastomer, vinyl chloride elastomer, urethane elastomer, ester elastomer, amide elastomer, ethylene-vinyl acetate copolymer, natural rubber, butadiene rubber, silicon rubber, ethylene propylene diene monomer, nitrile rubber and chloroprene rubber;

and/or, in step 1, the laser absorber is one or more of copper salt, copper oxide, copper hydroxide, copper organic complex, bismuth salt, bismuth oxide, bismuth hydroxide, bismuth organic complex, chromium salt, chromium oxide, chromium hydroxide, chromium organic complex, tin salt, tin oxide, tin hydroxide, tin organic complex, tin doped oxide, antimony salt, antimony oxide, antimony hydroxide, antimony organic complex, indium salt, indium oxide, indium hydroxide, and indium organic complex;

and/or, in the step 2, the metal is a conductive metal;

and/or in the step 3, the liquid metal is one or two of a gallium simple substance and a gallium-based alloy.

3. The method of claim 2, wherein: in the step 1, the styrene elastomer is selected from SBS, SIS, SEBS or SEPS, the olefin elastomer is selected from POE, TPE or TPV, the diene elastomer is selected from TPB or TPI, the vinyl chloride elastomer is selected from TPVC or TCPE, the urethane elastomer is TPU, the ester elastomer is TPEE, the amide elastomer is TPAE, and the ethylene-vinyl acetate copolymer is EVA; the mass ratio of the laser absorber to the polymer is 0.1-20 wt.%, preferably 3-10 wt.%;

in step 2, the conductive metal is selected from copper, gold, chromium or nickel;

in step 3, the gallium-based alloy is an alloy formed by gallium and at least one element of indium, tin, zinc and bismuth, and is preferably one or more of gallium-indium alloy, gallium-tin alloy, gallium-zinc alloy, gallium-indium-tin alloy, gallium-indium-zinc alloy, gallium-indium-tin-zinc alloy and gallium-indium-tin-bismuth alloy.

4. The method of claim 1, wherein: in step 3, the alkaline solution is one or more than two aqueous solutions of lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, calcium hydroxide, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, urotropine, sodium methoxide, potassium ethoxide, potassium tert-butoxide, pyridine, triethylenetetramine, tetraethylenepentamine, urea and ammonia water;

the acid solution is one or more than two aqueous solutions of hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen fluoride, sulfuric acid, sulfurous acid, phosphoric acid, nitric acid, formic acid, acetic acid, propionic acid, acrylic acid, sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, nitrous acid, pyruvic acid, oxalic acid, succinic acid, adipic acid, hydrobromic acid, boric acid, oxalic acid, tartaric acid, ascorbic acid, benzoic acid, salicylic acid and citric acid.

5. The method of claim 4, wherein: the concentration of the alkaline solution is as follows: 0.01mol/L-10 mol/L; the concentration of the acid solution is as follows: 0.01mol/L-10 mol/L.

6. The production method according to any one of claims 1 to 5, characterized in that: in the step 2, the wavelength of the laser is 190-1200 nm, and the plating mode is chemical plating deposition;

in step 3, the metal pattern is coated with liquid metal by brushing the liquid metal on the metal pattern, and the pattern comprises a circuit and decorative patterns or figures.

7. The method of claim 6, wherein: in step 2, the wavelength of the laser is 192nm, 355nm or 1064nm, the laser power is 1.5-8W, the laser scanning speed is 1000-2000mm/s, and the laser frequency is 40-80 kHz.

8. A flexible liquid metal pattern produced by the method of any one of claims 1 to 7.

9. A flexible electronic device, characterized in that: comprising a flexible liquid metal pattern according to claim 8.

10. Use of the flexible liquid metal pattern of claim 9 in the manufacture of a flexible electronic device.

Technical Field

The invention belongs to the field of flexible sensors, and particularly relates to a flexible liquid metal pattern based on laser activation selective metallization and a preparation method thereof.

Background

With the rapid development of the electronic information industry in China, China has become a world with a large number of electronic information product manufacturing and export countries. The traditional hard circuit board has the advantages of high rigidity, high integration degree, strong interconnectivity and the like, can realize high integration of electronic devices in the using process, can effectively protect electronic elements from being physically damaged, and has the defects that electronic products do not have bending and stretching functions and the like. With the development of the times, the demands of people on flexible electronics, wearable equipment and implantable medical equipment are gradually increased, the traditional rigid electronic equipment is difficult to meet the development demand of instrument and equipment flexibility, and the application breadth and the development prospect of the traditional rigid electronic equipment are seriously hindered. In order to meet the requirements of flexibility, light weight and miniaturization of instruments and equipment and to improve the flexibility of electronic circuits, people gradually pay attention to the idea of forming patterns with bending capability and even stretching function on the surface of a flexible material.

The flexible printed circuit board is also called flexible printed circuit board, and is an electronic circuit with certain bending capability prepared on a flexible substrate by utilizing a copper-clad or printing process. The liquid metal is a flexible metal which is liquid at normal temperature and has proper conductivity, bendability and ductility. The liquid metal can be stretched dozens of times without breaking; even if broken, the cable can still automatically recover as long as the cable is still in place. Therefore, liquid metal is a very potential flexible conductive material, and how to print flexible liquid metal patterns (including circuits and decorative patterns or figures) on the surface of a substrate material according to requirements becomes a focus of research. At present, conductive fibers such as nano silver or nano graphene are used as conductive media to prepare conductive ink, and a conductive path is formed on a flexible substrate through screen printing, laser sintering, 3D printing and other modes, so that a foldable and stretchable flexible circuit is realized. However, the flexible circuit manufactured by the process mainly relies on the mesh-shaped stacking of the conductive fibers to realize the conductivity, and has the defects of weak conductivity, short service life, expensive price of the nano silver and the nano graphene and the like, thereby seriously limiting the industrial application of the flexible circuit. The traditional copper-clad circuit production process has many process limitations in the use of flexible substrates, for example, a mask is needed in a lithography method, and if flexible liquid metal patterns with different patterns are needed to be prepared, the corresponding mask needs to be redesigned and prepared, which is not beneficial to industrial mass production; the disadvantages of the microfluid injection method are similar to those of the lithography method, and each time the microfluid injection method is used for preparing a flexible liquid metal pattern, one microfluid chip is required to be consumed, and the microfluid chip is obtained through a series of soft lithography processes, so that the process is complex; the limitations of additive methods such as direct writing and 3D printing are that specially designed liquid metal printing devices are required, which are expensive, and the special physical and chemical properties of liquid metal make it less convenient to print than ordinary ink.

The document (research on the forming process of the flexible substrate surface electronic circuit based on laser induction, a master research student's academic paper of the professional academic level of the southwest university of science and technology, 2019) reports the forming process of the flexible substrate surface electronic circuit based on laser induction, the process takes a polyimide film as a matrix, the matrix is etched by femtosecond laser, a large number of etched micropores are formed on the surface of the modified matrix, the roughness and the hydrophilicity of the matrix are obviously improved, and a place is provided for coating of an activating solution and adsorption of activated particles. An acidic activating solution prepared by taking copper sulfate, sodium hypophosphite, sodium hexametaphosphate and lactic acid as active ingredients is coated on the surface of the modified substrate to form an activating solution film layer, and the substrate is activated before electroless copper plating by irradiation induction of a 450nm blue laser. And forming a layer of circuit pattern with catalytic activity on the surface of the activated substrate, detecting that the active component is copper particles, and finally preparing the electronic circuit on the surface of the flexible material by a copper plating process. However, the femtosecond laser adopted for etching treatment in the process is expensive and the process cost is high; in addition, the copper circuit prepared by the process has poor conductivity in a bent and stretched state, and loses conductivity in the bent state, particularly in the stretched state, because the rigid copper layer is easy to break.

Therefore, there is a need to develop a flexible metal pattern which has excellent conductive performance under bending and stretching conditions, excellent self-repairing performance and acid/alkali corrosion resistance, controllable preparation cost and suitability for large-scale industrial production.

Disclosure of Invention

The invention aims to provide a flexible liquid metal pattern based on laser activation selective metallization and a preparation method and application thereof.

The invention provides a preparation method of a flexible liquid metal pattern, which comprises the following steps:

step 1: uniformly mixing the polymer and the laser absorbent, carrying out melt blending, extruding and granulating, and then forming the obtained granules to obtain the polymer/laser absorbent flexible composite material;

step 2: irradiating the surface of the polymer/laser absorber flexible composite material by using laser, forming an activated pattern in an irradiation area, and then plating metal in the irradiation area to obtain a metal pattern;

and step 3: and (3) immersing the polymer/laser absorbent flexible composite material treated in the step (2) into an acidic or alkaline solution, and coating liquid metal on the metal pattern to obtain a flexible liquid metal pattern.

Further, in step 1, the polymer is one or more of a styrene elastomer, an olefin elastomer, a diene elastomer, a vinyl chloride elastomer, a urethane elastomer, an ester elastomer, an amide elastomer, an ethylene-vinyl acetate copolymer, natural rubber, butadiene rubber, silicone rubber, ethylene propylene diene rubber, nitrile rubber, and chloroprene rubber;

and/or, in step 1, the laser absorber is one or more of copper salt, copper oxide, copper hydroxide, copper organic complex, bismuth salt, bismuth oxide, bismuth hydroxide, bismuth organic complex, chromium salt, chromium oxide, chromium hydroxide, chromium organic complex, tin salt, tin oxide, tin hydroxide, tin organic complex, tin doped oxide, antimony salt, antimony oxide, antimony hydroxide, antimony organic complex, indium salt, indium oxide, indium hydroxide, and indium organic complex;

and/or, in the step 2, the metal is a conductive metal;

and/or in the step 3, the liquid metal is one or two of a gallium simple substance and a gallium-based alloy.

Further, in step 1, the styrene elastomer is selected from SBS, SIS, SEBS or SEPS, the olefin elastomer is selected from POE, TPE or TPV, the diene elastomer is selected from TPB or TPI, the vinyl chloride elastomer is selected from TPVC or TCPE, the urethane elastomer is TPU, the ester elastomer is TPEE, the amide elastomer is TPEE, and the ethylene-vinyl acetate copolymer is EVA; the mass ratio of the laser absorber to the polymer is 0.1-20 wt.%, preferably 3-10 wt.%;

in step 2, the conductive metal is selected from copper, gold, chromium or nickel;

in step 3, the gallium-based alloy is an alloy formed by gallium and at least one element of indium, tin, zinc and bismuth, and is preferably one or more of gallium-indium alloy, gallium-tin alloy, gallium-zinc alloy, gallium-indium-tin alloy, gallium-indium-zinc alloy, gallium-indium-tin-zinc alloy and gallium-indium-tin-bismuth alloy.

Further, in step 3, the alkaline solution is one or more aqueous solutions of lithium hydroxide, sodium hydroxide, potassium hydroxide, barium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, calcium hydroxide, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, urotropine, sodium methoxide, potassium ethoxide, potassium tert-butoxide, pyridine, triethylenetetramine, tetraethylenepentamine, urea, and ammonia water;

the acid solution is one or more than two aqueous solutions of hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen fluoride, sulfuric acid, sulfurous acid, phosphoric acid, nitric acid, formic acid, acetic acid, propionic acid, acrylic acid, sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, nitrous acid, pyruvic acid, oxalic acid, succinic acid, adipic acid, hydrobromic acid, boric acid, oxalic acid, tartaric acid, ascorbic acid, benzoic acid, salicylic acid and citric acid.

Further, the concentration of the alkaline solution is as follows: 0.01mol/L-10 mol/L; the concentration of the acid solution is as follows: 0.01mol/L-10 mol/L.

Further, in the step 2, the wavelength of the laser is 190-1200 nm, and the plating mode is chemical plating deposition;

in step 3, the metal pattern is coated with liquid metal by brushing the liquid metal on the metal pattern, and the pattern comprises a circuit and decorative patterns or figures.

Further, in step 2, the wavelength of the laser is 192nm, 355nm or 1064nm, the laser power is 1.5-8W, the laser scanning speed is 1000-2000mm/s, and the laser frequency is 40-80 kHz.

The invention also provides the flexible liquid metal pattern prepared by the method.

The invention also provides a flexible electronic device which comprises the flexible liquid metal pattern.

The invention also provides application of the flexible liquid metal pattern in preparation of flexible electronic equipment.

"tin-doped oxides" include tin-doped antimony oxide, tin-doped indium oxide, tin-doped titanium oxide, tin-doped cadmium oxide, or tin-doped tungsten oxide.

The flexible liquid metal pattern can be a circuit diagram in flexible electronic equipment, and can also be a pattern or a figure with a decorative effect.

Compared with the prior art, the technical scheme provided by the invention has the beneficial effects that:

(1) the preparation method of the invention does not need to manufacture a mask, and the pattern can be freely designed through software, and if flexible liquid metal patterns with different patterns are to be prepared, the pattern to be printed is only required to be replaced in laser control software; compared with the traditional method (such as a lithography method, a microfluid injection method and the like) which needs to manufacture a mask, the method has the advantages of good production flexibility, simple operation, controllable cost and large-scale industrial application prospect.

(2) The preparation method of the invention does not need expensive equipment, and the cost of the used laser is lower.

(3) At present, most of preparation methods of flexible liquid metal patterns can only prepare planar flexible liquid metal patterns, but the method of the invention can not only prepare planar flexible liquid metal patterns, but also prepare three-dimensional flexible liquid metal patterns.

(4) Compared with the flexible liquid metal pattern prepared by the traditional method, the flexible liquid metal pattern prepared by the method has good flexibility and excellent conductivity under bending and stretching conditions;

(5) the flexible liquid metal pattern prepared by the method has excellent self-repairing property and acid/alkali corrosion resistance, and has wide application prospect in preparing flexible electronic equipment with special application (such as application in acid or alkali environment).

According to the present invention, it is possible to make various modifications, substitutions and alterations without departing from the basic technical idea of the present invention as described above, according to the common technical knowledge and conventional means in the field.

The present invention will be described in further detail with reference to the following examples. This should not be understood as limiting the scope of the above-described subject matter of the present invention to the following examples. All the technologies realized based on the above-mentioned contents of the present invention belong to the scope of the present invention.

Detailed Description

The raw materials and equipment used in the invention are known products and are obtained by purchasing commercial products.

Styrene-ethylene/propylene copolymer-styrene triblock copolymer (SEPS) is available from Coloray, Inc. under the HYBRAR trademark^TM7311F. Hydrogenated styrene-butadiene block copolymer (SEBS) was purchased from the petrochemical company of British, China under the designation YH-506. Thermoplastic polyurethane elastomer rubber (TPU) is available from Basv (China) Inc. under the designation 3096. Thermoplastic polyester elastomer (TPEE) is available from DuPont, U.S. under the 4096 designation. Polyolefin elastomers (POE) are available from Exxon Mobil chemical, USA under the designation 6202.

Copper oxalate was purchased from DAZHENGJIYUAN New Material science and technology, Inc., tin dioxide was purchased from Xian chemical reagent, copper pyrophosphate was purchased from DAZHENGJIYU New Material science and technology, Inc., and copper phosphate was purchased from DAZHENGJIYU New Material science and technology, Inc.

Bismuth oxide, hydroiodic acid, acrylic acid, citric acid, phosphoric acid, hydrochloric acid, sodium carbonate, triethanolamine, ammonia water, sodium bicarbonate, and sodium hydroxide were purchased from the chemical reagent plant of Synechocystis.

The chemical copper plating solution is purchased from Dazhangjiyuan New Material science and technology Co., Ltd, and the concentration of anhydrous copper sulfate in the chemical copper plating solution is 6-12 g/L.

Various liquid metals, such as elemental gallium, gallium-indium alloy, gallium-tin alloy, gallium-indium-tin alloy, and gallium-indium-tin-zinc alloy, are commercially available from Shenyang Shanghai trades Ltd.

A double-screw extruder: nanjing Jennt electromechanical Co., Ltd., model number SHJ-25.

An injection molding machine: haitian machinery, Inc. model number MA 600.

The plane laser marking machine is a model MF-E-A, pulse laser, 20W of the maximum power of a laser, 1064nm of laser wavelength and Guangdong Dai YueMing group laser company.

A plane laser marking machine is a type MUV-E-R, pulse laser, a laser maximum power of 5W, a laser wavelength of 355nm, Guangdong Dai YueMing laser group company.

The plane laser marking machine is MV-U, pulse laser, 2W of the maximum power of the laser, 192nm of the laser wavelength and Picker International laser corporation.

Three-dimensional laser marking machine, model MF-D-A, pulsed laser, laser maximum power 20W, laser wavelength 1064nm, Guangdong Dai Yue Ming laser group Limited company.

Three-dimensional laser marking machine, model MUV-E-3DR, pulse laser, maximum power of laser 5W, laser wavelength 355nm, Dida laser equipment Limited.

Three-dimensional laser marking machine, model MV-U3D, pulse laser, laser maximum power 2W, laser wavelength 192nm, Peak International laser corporation.

Example 1

Mixing tin dioxide with SEPS in an amount of 5 wt.%, melt-blending and extruding (at the temperature of 210 ℃) by a double-screw extruder, granulating, and injection-molding the obtained granules (at the temperature of 260 ℃) to prepare the polymer/laser absorber flexible composite material standard sample plate. The surface of the polymer/laser absorbent flexible composite material standard sample plate is irradiated by plane near-infrared pulse laser (with the wavelength of 1064nm) for laser activation, the laser power is 4W, the laser scanning speed is 1000mm/s, and the laser frequency is 40 kHz. And immersing the polymer/laser absorbent flexible composite material standard sample plate subjected to laser irradiation into chemical copper plating solution, and plating copper for 10min at 50 ℃ to obtain the conductive copper pattern. Dripping the gallium simple substance on a standard sample plate of the polymer/laser absorbent flexible composite material after copper plating in 0.01mol/L hydroiodic acid solution, and pushing the gallium simple substance by a nylon brush to prepare a flexible liquid metal pattern.

Example 2

The liquid metal used was gallium indium alloy, the acid solution was 0.5mol/L acrylic acid solution, and the other conditions were the same as in example 1.

Example 3

The liquid metal used was gallium-tin alloy, the acid solution was 1mol/L citric acid solution, and the other conditions were the same as in example 1.

Example 4

The liquid metal used was a gallium indium tin alloy, the acidic solution was a 5mol/L phosphoric acid solution, and the other conditions were the same as in example 1.

Example 5

The liquid metal is gallium indium tin zinc alloy, the acid solution is 10mol/L hydrochloric acid solution, and other conditions are the same as those in example 1.

Example 6

Mixing 10 wt.% of bismuth oxide with SEBS, performing melt blending extrusion (at the temperature of 210 ℃) by using a double-screw extruder, granulating, and performing injection molding (at the temperature of 230 ℃) on the obtained granules to prepare the polymer/laser absorber flexible composite material standard sample plate. The surface of the polymer/laser absorbent flexible composite material standard sample plate is irradiated by plane near-infrared pulse laser (with the wavelength of 1064nm) for laser activation, the laser power is 6W, the laser scanning speed is 2000mm/s, and the laser frequency is 40 kHz. And immersing the polymer/laser absorbent flexible composite material standard sample plate subjected to laser irradiation into chemical copper plating solution, and plating copper for 10min at 50 ℃ to obtain the conductive copper pattern. Dripping the gallium simple substance on a standard sample plate of the polymer/laser absorbent flexible composite material after copper plating in 0.01mol/L sodium carbonate solution, and pushing the gallium simple substance by a nylon brush to prepare a flexible liquid metal pattern.

Example 7

The liquid metal is gallium indium alloy, the alkaline solution is 0.5mol/L triethanolamine solution, and other conditions are the same as those in example 6.

Example 8

The liquid metal used was gallium-tin alloy, the alkaline solution was 1mol/L ammonia solution, and the other conditions were the same as in example 6.

Example 9

The liquid metal used was a gallium indium tin alloy, the alkaline solution was a 5mol/L sodium bicarbonate solution, and the other conditions were the same as in example 6.

Example 10

The liquid metal used was gallium indium tin zinc alloy, the alkaline solution was 10mol/L sodium hydroxide solution, and the other conditions were the same as in example 6.

Example 11

Mixing 3 wt.% of copper phosphate with TPU, performing melt blending extrusion (at the temperature of 200 ℃) by using a double-screw extruder, granulating, and performing injection molding (at the temperature of 210 ℃) on the obtained granules to prepare the polymer/laser absorber flexible composite material standard sample plate. The surface of the polymer/laser absorbent flexible composite material standard sample plate is irradiated by plane ultraviolet pulse laser (with the wavelength of 355nm) to carry out laser activation, the laser power is 3W, the laser scanning speed is 2000mm/s, and the laser frequency is 50 kHz. And immersing the polymer/laser absorbent flexible composite material standard sample plate subjected to laser irradiation into chemical copper plating solution, and plating copper for 10min at 50 ℃ to obtain the conductive copper pattern. Dripping the gallium simple substance on a standard sample plate of the polymer/laser absorbent flexible composite material after copper plating in 0.01mol/L hydroiodic acid solution, and pushing the gallium simple substance by a nylon brush to prepare a flexible liquid metal pattern.

Example 12

The liquid metal used was gallium indium alloy, the acid solution was 0.5mol/L acrylic acid solution, and the other conditions were the same as in example 11.

Example 13

The liquid metal used was gallium-tin alloy, the acid solution was 1mol/L citric acid solution, and the other conditions were the same as in example 11.

Example 14

The liquid metal used was a gallium indium tin alloy, the acidic solution was a 5mol/L phosphoric acid solution, and the other conditions were the same as in example 11.

Example 15

The liquid metal used was gallium indium tin zinc alloy, the acidic solution was 10mol/L hydrochloric acid solution, and the other conditions were the same as in example 11.

Example 16

Mixing 7 wt.% of copper pyrophosphate with TPEE, melting, blending, extruding (at the temperature of 200 ℃) and granulating by using a double-screw extruder, and carrying out injection molding (at the temperature of 210 ℃) on the obtained granules to prepare the polymer/laser absorber flexible composite material standard sample plate. The surface of the polymer/laser absorbent flexible composite material standard sample plate is irradiated by planar pulse laser (with the wavelength of 192nm) to carry out laser activation, the laser power is 1.5W, the laser scanning speed is 2000mm/s, and the laser frequency is 60 kHz. And immersing the polymer/laser absorbent flexible composite material standard sample plate subjected to laser irradiation into chemical copper plating solution, and plating copper for 10min at 50 ℃ to obtain the conductive copper pattern. Dripping the gallium simple substance on a standard sample plate of the polymer/laser absorbent flexible composite material after copper plating in 0.01mol/L sodium carbonate solution, and pushing the gallium simple substance by a nylon brush to prepare a flexible liquid metal pattern.

Example 17

The liquid metal used was gallium indium alloy, the alkaline solution was 0.5mol/L triethanolamine solution, and the other conditions were the same as in example 16.

Example 18

The liquid metal used was gallium-tin alloy, the alkaline solution was 1mol/L ammonia solution, and the other conditions were the same as in example 16.

Example 19

The liquid metal used was a gallium indium tin alloy, the alkaline solution was a 5mol/L sodium bicarbonate solution, and the other conditions were the same as in example 16.

Example 20

The liquid metal used was gallium indium tin zinc alloy, the alkaline solution was 10mol/L sodium hydroxide solution, and the other conditions were the same as in example 16.

Example 21

Mixing copper oxalate with POE (polyolefin elastomer) in an amount of 7 wt.%, melting, blending, extruding (at the temperature of 180 ℃) and granulating by using a double-screw extruder, and performing injection molding (at the temperature of 200 ℃) on the obtained granules to prepare the polymer/laser absorbent flexible composite material standard sample plate. The surface of the polymer/laser absorbent flexible composite material standard sample plate is irradiated by plane near-infrared pulse laser (with the wavelength of 1064nm) for laser activation, the laser power is 8W, the laser scanning speed is 2000mm/s, and the laser frequency is 80 kHz. And immersing the polymer/laser absorbent flexible composite material standard sample plate subjected to laser irradiation into chemical copper plating solution, and plating copper for 10min at 50 ℃ to obtain the conductive copper pattern. Dripping the gallium simple substance on a standard sample plate of the polymer/laser absorbent flexible composite material after copper plating in 0.01mol/L hydroiodic acid solution, and pushing the gallium simple substance by a nylon brush to prepare a flexible liquid metal pattern.

Example 22

The liquid metal used was gallium indium alloy, the acid solution was 0.5mol/L acrylic acid solution, and the other conditions were the same as in example 21.

Example 23

The liquid metal used was gallium-tin alloy, the acid solution was 1mol/L citric acid solution, and the other conditions were the same as in example 21.

Example 24

The liquid metal used was a gallium indium tin alloy, the acidic solution was a 5mol/L phosphoric acid solution, and the other conditions were the same as in example 21.

Example 25

The liquid metal used was gallium indium tin zinc alloy, the acidic solution was 10mol/L hydrochloric acid solution, and the other conditions were the same as in example 21.

Example 26

The laser used was a three-dimensional near-infrared pulsed laser (wavelength 1064nm), the injection mold was a three-dimensional conical mold, the acid solution was a 0.01mol/L phosphoric acid solution, and the other conditions were the same as in example 1.

Example 27

The laser used was three-dimensional near-infrared pulse laser (wavelength 1064nm), the injection mold was a three-dimensional conical mold, the liquid metal was gallium-indium alloy, the acid solution was 0.5mol/L hydrochloric acid solution, and the other conditions were the same as in example 6.

Example 28

The laser used was a three-dimensional pulse laser (wavelength 355nm), the injection mold was a three-dimensional conical mold, the liquid metal was gallium-tin alloy, the alkaline solution was 1mol/L ammonia solution, and the other conditions were the same as in example 11.

Example 29

The laser used was a three-dimensional pulse laser (wavelength 192nm), the injection mold was a three-dimensional conical mold, the liquid metal was gallium indium tin alloy, the alkaline solution was 5mol/L sodium bicarbonate solution, and the other conditions were the same as in example 16.

Example 30

The laser used was three-dimensional near-infrared pulse laser (wavelength 1064nm), the injection mold was a three-dimensional conical mold, the liquid metal was gallium indium tin zinc alloy, the alkaline solution was 10mol/L sodium hydroxide solution, and the other conditions were the same as in example 21.

The following is a method for preparing a control sample.

Comparative example 1

The laser absorber was not added, and the other conditions were the same as in example 26.

Comparative example 2

The laser absorber was not added, and the other conditions were the same as in example 27.

Comparative example 3

The laser absorber was not added, and the other conditions were the same as in example 28.

Comparative example 4

The laser absorber was not added, and the other conditions were the same as in example 29.

Comparative example 5

The laser absorber was not added, and the other conditions were the same as in example 30.

Comparative example 6

The liquid metal was brushed in air, and other conditions were the same as in example 26.

Comparative example 7

The liquid metal was brushed in air, and other conditions were the same as in example 27.

Comparative example 8

The liquid metal was brushed in air, and other conditions were the same as in example 28.

Comparative example 9

The liquid metal was brushed in air, and the other conditions were the same as in example 29.

Comparative example 10

The liquid metal was brushed in air, and other conditions were the same as in example 30.

Comparative example 11

The liquid metal was brushed in deionized water, otherwise conditions were consistent with example 26.

Comparative example 12

The liquid metal was brushed in deionized water, otherwise conditions were consistent with example 27.

Comparative example 13

The liquid metal was brushed in deionized water, otherwise conditions were consistent with example 28.

Comparative example 14

The liquid metal was brushed in deionized water, otherwise conditions were consistent with example 29.

Comparative example 15

The liquid metal was brushed in deionized water, otherwise conditions were consistent with example 30.

Comparative example 16

The liquid metal used was mercury, and the other conditions were the same as in example 26.

Comparative example 17

The liquid metal used was mercury and the other conditions were the same as in example 27.

Comparative example 18

The liquid metal used was mercury, and the other conditions were the same as in example 28.

Comparative example 19

The liquid metal used was mercury and the other conditions were in accordance with example 29.

Comparative example 20

The liquid metal used was mercury, and the other conditions were the same as in example 30.

Comparative example 21

After copper plating, the liquid metal was not brushed, and the other conditions were the same as in example 26.

Comparative example 22

After copper plating, the liquid metal was not brushed, and the other conditions were the same as in example 27.

Comparative example 23

After copper plating, the liquid metal was not brushed, and the other conditions were the same as in example 28.

Comparative example 24

After copper plating, the liquid metal was not brushed, and the other conditions were the same as in example 29.

Comparative example 25

After copper plating, the liquid metal was not brushed, and the other conditions were the same as in example 30.

Comparative example 26

After a polymer/laser absorber flexible composite master plate was prepared by the conditions of example 26, a liquid metal pattern was prepared on the master plate by a stencil printing method.

Comparative example 27

After a polymer/laser absorber flexible composite master plate was prepared by the conditions of example 27, a liquid metal pattern was prepared on the master plate by a stencil printing method.

Comparative example 28

After a polymer/laser absorber flexible composite master plate was prepared by the conditions of example 28, a liquid metal pattern was prepared on the master plate by a stencil printing method.

Comparative example 29

After a polymer/laser absorber flexible composite master plate was prepared by the conditions of example 29, a liquid metal pattern was prepared on the master plate by a stencil printing method.

Comparative example 30

After a polymer/laser absorber flexible composite master plate was prepared by the conditions of example 30, a liquid metal pattern was prepared on the master plate by a stencil printing method.

The beneficial effects of the present invention are demonstrated by the following experimental examples.

Experimental example 1 bending/tensile resistance, acid/base corrosion resistance and self-repairing Property test

1. Experimental methods

Bending resistance/tensile resistance test: the resistance of the resulting flexible liquid metal pattern was measured with a multimeter at 90 ° bend and 100% tensile strain.

And (3) acid corrosion resistance detection: 1mol/L hydrochloric acid solution is dripped on the pattern, and the corrosion phenomenon is observed after 10 min.

And (3) detecting alkali corrosion resistance: dropping 1mol/L sodium hydroxide solution on the pattern, and observing corrosion phenomenon after 10 min.

And (3) self-repairability detection: and (3) connecting the obtained flexible liquid metal pattern into a circuit connected with an LED lamp, and scratching the flexible liquid metal pattern with a small knife, wherein if the LED lamp is extinguished, the self-repairability is poor, and otherwise, if the LED lamp is not extinguished, the self-repairability is good.

All the liquid metal patterns used for testing the bending resistance/tensile resistance, the acid/alkali corrosion resistance and the self-repairability in this experimental example were rectangular patterns having a length of 50mm and a width of 1.5 mm.

2. Results of the experiment

The test results are shown in table 1.

Bending resistance/tensile resistance: "unable to adhere" means that the liquid metal cannot adhere to the substrate, and the liquid metal pattern cannot be formed, so that the bending resistance/tensile resistance test cannot be performed; "non-selective" means that the liquid metal can adhere to both the copper-bearing and non-copper bearing areas, cannot selectively adhere to the copper-bearing areas, cannot form a liquid metal pattern, and therefore, no bend resistance/tensile resistance test is performed; "OL" represents an over load, i.e., a resistance of infinity (open circuit).

Acid/base corrosion resistance: "good" means that no significant corrosion of the liquid metal pattern after 10min acid/base treatment occurred compared to before treatment; "non-stick" means that the liquid metal does not stick to the substrate, does not form a liquid metal pattern, and therefore, cannot be subjected to an acid/base corrosion resistance test; "non-selective" means that the liquid metal can adhere to both copper and non-copper areas, does not selectively adhere to copper areas, does not form a liquid metal pattern, and therefore is not tested for acid/base corrosion resistance; "poor" means that the corrosion phenomenon is obviously found in the liquid metal pattern after 10min of acid/alkali treatment compared with the liquid metal pattern before treatment, and the pattern is seriously damaged; "No" means no brushing of the liquid metal and therefore no acid/base corrosion resistance test was performed.

In self-repairability: "good" means that the LED lamp is not extinguished and there is no significant change in brightness, i.e. the circuit is still on; "non-adhesion" means that the liquid metal cannot adhere to the substrate, and a liquid metal pattern cannot be formed, so that a self-repairability test cannot be performed; "non-selective" means that the liquid metal can adhere to both the copper-bearing and non-copper bearing areas, cannot selectively adhere to the copper-bearing areas, cannot form a liquid metal pattern, and therefore, no self-healing test is performed; "poor" indicates that the LED lamp is off, i.e., the circuit is open.

"none" in the feed parameters of Table 1 indicates that the corresponding material was not used.

Table 1 results of performance test of each liquid metal pattern

As can be seen from table 1, in examples 1 to 25, the preparation of the flexible liquid metal pattern on the surface of the planar polymer/laser absorber flexible composite material was successfully achieved by using various polymers, laser absorbers, acidic or alkaline solutions, and liquid metals, and the prepared flexible liquid metal pattern had good conductivity (small resistance) under bending and stretching conditions, the pattern was hardly corroded after being treated with the acidic or alkaline solutions, and remained conductive (the LED lamp was not extinguished) after being subjected to small scratching, and had good acid/alkaline corrosion resistance and self-repairing performance.

In examples 26 to 30, the preparation of the flexible liquid metal pattern is realized on the surface of the three-dimensional tapered polymer/laser absorber flexible composite material, and the prepared three-dimensional flexible liquid metal pattern has good conductivity, acid/alkali corrosion resistance and self-repairing performance.

Comparative examples 1 to 5, in which no laser absorber was added, copper patterns could not be formed during electroless copper plating after laser irradiation, and thus liquid metal could not adhere in an acidic or alkaline solution. Comparative examples 6 to 10, and 11 to 15, where liquid metal was brushed in air and deionized water, it was found that there was no selectivity in brushing liquid metal in air and deionized water, i.e., both areas with and without copper could be brushed with liquid metal; in acidic or alkaline solutions, however, only areas with copper can be brushed with liquid metal, while areas without copper do not, and liquid metal selectively adheres to the copper surface. Acidic or basic solutions are therefore necessary in the process of the invention. The liquid metal used in comparative examples 16 to 20 was mercury, which did not adhere to the surface of the copper pattern in an acidic or alkaline solution, and did not form a liquid metal pattern. Comparative examples 21 to 25 copper-plated without brushing liquid metal, the resulting copper pattern was poor in both bending conductivity and tensile conductivity, and the copper pattern was poor in self-repairability, and was powered off after small scratches (LED lamp extinguished).

Comparative examples 26 to 30 liquid metal patterns were prepared on a polymer/laser absorber flexible composite standard template by a stencil printing method, and although the conductivity and the self-repairability were good, the acid/alkali corrosion resistance was poor. This is because the flexible liquid metal pattern prepared by the method of the present invention has better acid/base corrosion resistance than the conventional method of preparing a flexible liquid metal pattern (e.g., stencil printing method), and is suitable for preparing an acid/base corrosion resistant circuit pattern. Because of the huge surface tension of gallium-indium alloy, the principle of the traditional preparation method of the flexible liquid metal pattern is based on the adhesive force between the surface gallium oxide and the base material, the gallium oxide is easy to react with acid/alkali, and the liquid metal losing the gallium oxide cannot spread on the surface of the base material due to the huge surface tension, curls into balls and shows the phenomenon of corrosion. The principle of the method of the present invention may be based on the unknown interaction of liquid metal with copper, rather than gallium oxide, and therefore has better acid/base corrosion resistance.

In summary, the present invention provides a flexible liquid metal pattern based on laser activation selective metallization and a method for manufacturing the same. The preparation method of the invention does not need a mask, the pattern can be freely designed through software, the production flexibility is good, the operation is simple, the cost is controllable, and the preparation method is suitable for large-scale industrial application. The flexible liquid metal pattern prepared by the method has good flexibility, excellent conductivity under bending and stretching conditions, excellent self-repairability and acid/alkali corrosion resistance, and wide application prospect in the field of flexible sensors.