CN108389645B - Preparation method of liquid metal conductive filler based on liquid-solid two-phase structure - Google Patents

Abstract

The invention discloses a preparation method of a liquid metal conductive filler based on a liquid-solid two-phase structure. The preparation method comprises the following steps: carrying out dispersion stirring or ball milling on the organic modified solid conductive filler and liquid metal in a solvent to react, and removing the solvent after the reaction is finished to obtain the liquid metal conductive filler based on a liquid-solid two-phase structure; or the liquid metal is directly coated on the surface of the solid conductive filler through vacuum evaporation to obtain the liquid metal conductive filler based on a liquid-solid two-phase structure. The preparation method disclosed by the invention is simple in process and low in energy consumption, and the prepared conductive filler is a liquid-solid two-phase conductive filler with a liquid metal structure, has the deformation-conductive stability characteristic, and has an important application prospect in the field of preparation of high-performance and high-stability flexible conductive functional elastomers.

Description

A kind of preparation method of liquid metal conductive filler based on liquid-solid two-phase structure

technical field

The invention relates to the field of functional conductive materials, in particular to a preparation method of a liquid metal conductive filler based on a liquid-solid two-phase structure.

Background technique

Conductive fillers with a liquid-solid two-phase structure have important application prospects in the field of elastic and conductive functional materials, especially in high-deformable conductive composite materials, flexible thermally conductive materials, and stretchable conductors. Traditional elastic conductive functional materials are mainly prepared by blending rigid fillers and flexible polymer matrix. The disadvantage of such conductors is that the Young's modulus of conductive fillers (10 ⁹ -10 ¹² Pa) is higher than that of the matrix. About 5-6 orders of magnitude, the rigid conductive filler cannot change with the deformation of the matrix, which in turn causes the interface between the conductive filler and the matrix to slip, fall off, crack, and crack, resulting in irreversible damage to the conductive network. Therefore, the design and preparation of conductors with high flexibility, high tensile strength, and low driving voltage with the reconfiguration and stabilization properties of the conductive network have important application prospects. The liquid metal is composed of gallium indium tin alloy that flows at room temperature, and its Young's modulus is 10 ⁵ -10 ⁶ Pa lower than that of the flexible substrate. Its characteristics endow it with important application value in constructing dynamic conductive networks.

To sum up, the present invention is based on the fact that the currently commonly used conductive functional elastomer is prepared by using rigid conductive fillers and composite flexible substrates, which inevitably generate interfaces when subjected to force and deform in various applications. Slippage, shedding, cracks, cracks cause structural damage to the conductive network. It is proposed to prepare liquid metal conductive fillers with a liquid-solid two-phase coexistence structure to construct a dynamic reversible and stable conductive network.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a liquid metal conductive filler based on a liquid-solid two-phase structure in view of the deficiencies of the prior art. The preparation method is simple in process and low in energy consumption, and the prepared conductive filler is a rigid conductive filler with a liquid metal structure and has the characteristics of deformation-conductivity stability.

The purpose of the present invention is achieved through the following technical solutions.

A preparation method of a liquid metal conductive filler based on a liquid-solid two-phase structure, comprising the following steps:

The organically modified solid conductive filler and the liquid metal are reacted by dispersing, stirring or ball milling in a solvent, and the solvent is removed after the reaction to obtain a liquid metal conductive filler based on a liquid-solid two-phase structure.

Further, the liquid metal is a liquid metal at room temperature, including one or more alloys of gallium, indium and tin.

Further, the solvent includes one of water, ethanol, N,N-dimethylformamide, acetone and toluene.

Further, the solid conductive filler includes conductive powder, silver nanowire, carbon fiber, carbon nanotube or graphene.

Further, the conductive powder includes conductive metal powder or conductive carbon black.

Further, the organic modification treatment includes a thiol group-containing coupling agent treatment or a pyrophosphate titanate coupling agent treatment.

Further, the mercapto-group-containing coupling agent includes γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, mercaptopropyltrimethoxysilane, mercaptoundecanoic acid or mercaptodecanoic acid. Hexanoic acid.

Further, the mass ratio of the liquid metal to the organically modified solid conductive filler is 1:10-20:1.

Further, the dispersion stirring is performed at 25-120° C. for 1-24 hours, and the stirring rate is 100-500 rpm.

Further, the ball milling is performed at 50-120° C. for 1-5 hours, and the ball-milling speed is 200-600 rpm.

Further, the liquid metal is directly coated on the surface of the solid conductive filler by vacuum evaporation to obtain a liquid metal conductive filler based on a liquid-solid two-phase structure.

Further, the vacuum evaporation is to evaporate under vacuum conditions at 200-300° C. for 5-30 minutes.

The principle of the preparation method of the invention is as follows: interface coupling between the liquid metal and the solid conductive filler through chemical bonds (including polar covalent bonds or hydrogen bonds) and atomic van der Waals forces to form a liquid metal two-phase structure with a stable interface structure for electrical conductivity filler.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The preparation method of the invention has simple process and low energy consumption, the prepared conductive filler is a rigid conductive filler with a liquid metal structure, and has the characteristics of deformation-conductivity stability, and the prepared conductive filler is in the field of preparing high-performance, high-stability flexible conductive functional elastomer It has important application prospects.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to specific embodiments, but the protection scope and embodiments of the present invention are not limited thereto.

Example 1

The preparation of zero-dimensional carbon black-liquid metal two-phase conductive filler, the specific steps are as follows:

2 g of gallium-indium alloy (gallium:indium ratio of 4:1, g/g) was ultrasonically dispersed in ethanol, and 2 g of carbon black spherical particles treated with γ-mercaptopropyl trimethoxysilane were added, and stirred at 300 rpm at 60 °C. After 12 hours, the ethanol solvent was removed to obtain a zero-dimensional carbon black-gallium indium alloy two-phase conductive filler connected by chemical bond sulfhydryl groups.

The conductivity of the prepared zero-dimensional carbon black-gallium indium alloy two-phase conductive filler was increased from 1.42×10-6Ω·m to the conductor conductivity of 2.42×10-6Ω·m, and its conductivity stability could be increased from tensile deformation to 2% When it is increased to 15%, the preparation of flexible conductors with high tensile strength and high electrical conductivity is greatly improved, and it has important application prospects in the preparation of high-stability conductive materials.

Example 2

The preparation of one-dimensional silver fiber-gallium indium tin alloy two-phase conductive filler, the specific steps are as follows:

Ultrasonic disperse 5g gallium indium tin alloy (gallium:indium:tin ratio is 3:2:1, g/g/g) in ethanol, add 2g one-dimensional silver fiber treated with titanate coupling agent, and heat it at 60℃ Ball milling at 300 rpm for 2 hours to remove the ethanol solvent to obtain a one-dimensional silver fiber-gallium indium tin alloy two-phase conductive filler through the chemical bond of the coupling agent.

The conductivity of the prepared one-dimensional silver fiber-gallium indium tin alloy two-phase conductive filler is 3.12×10-6Ω·m, and its conductivity stability can be increased from 2% to 20% of tensile deformation, which is very useful for the preparation of high tensile and high tensile strength. The flexible conductor with stable electrical conductivity has a great improvement and has important application prospects in the preparation of high-stability conductive materials.

Example 3

The preparation of two-dimensional graphene-gallium two-phase conductive filler, the specific steps are as follows:

0.5 g of two-dimensional graphene was placed on the vacuum evaporation chamber substrate, evaporated at 240°C for 15 minutes, and gallium was coated on the graphene surface by evaporation to obtain two-dimensional graphene-gallium two-phase conductive fillers.

The conductivity of the prepared two-dimensional graphene-gallium two-phase conductive filler is 3.52×10 ^-6 Ω·m, and its conductivity stability can be increased from 2% to 25% of tensile deformation, which is stable for the preparation of high tensile and high conductivity. The flexible conductor has a great improvement and has important application prospects in the preparation of high-stability conductive materials.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (3)

1. A preparation method of a liquid metal conductive filler based on a liquid-solid two-phase structure is characterized by comprising the following steps:

carrying out dispersion stirring or ball milling on the organic modified solid conductive filler and liquid metal in a solvent to react, and removing the solvent after the reaction is finished to obtain the liquid metal conductive filler based on a liquid-solid two-phase structure; the liquid metal comprises one or more than two alloys of gallium, indium and tin; the organic modification treatment comprises coupling agent treatment containing sulfydryl or pyrophosphate titanate coupling agent treatment;

the coupling agent containing sulfydryl comprises gamma-mercaptopropyl trimethoxysilane, gamma-mercaptopropyl triethoxysilane, mercaptopropyl trimethoxysilane, mercaptoundecanoic acid or mercaptohexadecanoic acid; the mass ratio of the liquid metal to the organic modified solid conductive filler is 1: 10-20: 1; the dispersing and stirring is carried out at the temperature of 25-120 ℃ for 1-24 hours, and the stirring speed is 100-500 rpm; the ball milling is carried out for 1-5 hours at 50-120 ℃, and the ball milling rotating speed is 200-600 rpm.

2. The method of claim 1, wherein the solvent comprises one of water, ethanol, N-dimethylformamide, acetone, and toluene.

3. The production method according to claim 1, wherein the solid conductive filler comprises conductive powder, silver nanowires, carbon fibers, carbon nanotubes, or graphene; the conductive powder includes a conductive metal powder or a conductive carbon black.