CN111431498B

CN111431498B - Conductive polymer solution for crystal resonator and application thereof

Info

Publication number: CN111431498B
Application number: CN202010245410.8A
Authority: CN
Inventors: 徐禄波; 陈国飞; 方省众; 王骥; 张阳阳; 于开悬; 田昊
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS; Ningbo University
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS; Ningbo University
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2023-09-01
Anticipated expiration: 2040-03-31
Also published as: CN111431498A

Abstract

The invention relates to the technical field of electronic components and discloses a conductive polymer solution for a crystal resonator and application thereof, wherein the conductive polymer solution comprises the following raw material components in parts by mass: 80 to 98.5 portions of polar proton solution; 1-10 parts of modified polythiophene aqueous dispersion; 0.1 to 3 parts of nano graphite sheet aqueous dispersion; 0.01 to 0.05 part of dispersing agent; 0.01 to 0.05 portion of leveling agent; 0.01 to 0.05 portion of wetting agent. The nano graphite sheet with good water dispersibility is added into the modified polythiophene aqueous dispersion, the defect that micron-sized filler influences the flatness of the conductive coating is overcome, the wetting agent ensures that the conductive polymer solution has good wettability to the wafer, and the surface regularity of the coating and the spraying efficiency are improved. The conductive polymer solution is sprayed on the surface of the wafer through a spray gun to prepare the quartz wafer for the resonator, the surface of which is coated with the conductive polymer electrode. The wafer has electrodes with good conductivity, the surface resistance of the electrode can be as low as 232 omega, and the wafer is expected to replace metal silver to be applied to the field of crystal resonators.

Description

Conductive polymer solution for crystal resonator and application thereof

Technical Field

The invention relates to the technical field of electronic components, in particular to a conductive polymer solution for a crystal resonator and application thereof.

Background

The crystal resonator is a quartz crystal resonator made of quartz materials, commonly called crystal oscillator, is an electromechanical device made of quartz crystals with small electric loss through precise cutting and grinding and electrode welding lead wire plating, plays a role in generating frequency, has the characteristics of stability and good anti-interference performance, and is widely applied to various electronic products. If the crystal resonator is energized, it produces mechanical oscillations whose frequency is closely related to their shape, material, cutting direction, etc., and the size of electrodes used for quartz crystals at different frequency points is different.

The prior art crystal resonator is powered on by plating silver on the surface of the quartz crystal resonator and then connecting with the electrode. The metallic silver has good conductivity and oxidation stability, and is a common raw material for electrodes plated on the surface of the crystal resonator at present. The electrode material is generally silver with a purity of 99.99% or more, and a small amount of chromium (Cr) or nickel (Ni) is plated before silver plating in order to improve the adhesion strength of the electrode.

CN103684318A discloses a method for manufacturing a quartz crystal resonator with silver plated on the surface, which comprises the following steps in sequence: (1) cutting quartz crystal; (2) grinding the wafer; (3) measuring the angle by X-ray; (4) sticking a weight and grinding; (5) cutting and milling; (6) material melting and chamfering; (7) frequency sorting; step (8) etching, etching the surface of the wafer by using a chemical solvent; the method is characterized in that: the method also comprises the step (9) of cleaning, wherein the cleaning agent is used for removing the plaster, the greasy dirt and the chemical residual liquid of the wafer, and then the wafer is further cleaned by clean water; (10) Silver plating, wherein a silver layer is plated on the surface of the wafer according to the size of the electrode; (11) And (3) dispensing and solidifying the silver colloid on the upper frame, placing the silver-plated wafer on a fixed support, fixing the silver colloid, and then solidifying at the temperature of 100-120 ℃. The silver layer is uniform and easy to fall off, is convenient for fixing silver colloid and connecting with an electrode, is not easy to damage and has long service life.

CN 102832902a discloses a quartz crystal resonator and a processing method thereof, comprising a shell, a base, pins, a spring piece, conductive adhesive, a film-coated electrode and a wafer; the coated electrode comprises a basic electrode and a fine tuning electrode connected with the basic electrode; the wafer with the coated electrode attached to the wafer surface sequentially comprises a lower chromium plating layer, a silver plating layer and an upper chromium plating layer from inside to outside. The invention can improve the parasitic response characteristic of the quartz crystal resonator and greatly improve the performance and quality of the produced quartz crystal resonator.

However, the silver plating and chromium plating processes in the prior art have higher requirements on the process and the purity of the metal raw material, and the silver plating and chromium plating processes on the crystal surface have complex process and higher cost. Development of a novel electrode material with easy spraying and high conductivity is a key problem for improving the current wafer preparation process.

Disclosure of Invention

The invention aims to solve the problems of high technological requirements, complex process and high cost of silver plating on the surface of a crystal in the prior art, and provides a polymer solution which is easy to spray and high in conductivity.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the conductive polymer solution for the crystal resonator comprises the following raw material components in 100 parts by mass:

80 to 98.5 portions of polar proton solution;

1-10 parts of modified polythiophene aqueous dispersion;

0.1 to 3 parts of nano graphite sheet aqueous dispersion;

0.01 to 0.05 part of dispersing agent;

0.01 to 0.05 portion of leveling agent;

0.01 to 0.05 portion of wetting agent;

the mass ratio of the modified polythiophene aqueous dispersion to the nano graphite flake aqueous dispersion is 100:50-100:1.

Preferably, the mass ratio of the modified polythiophene aqueous dispersion to the nano graphite flake aqueous dispersion is 100:30-100:5, and under the condition that the mass ratio, the conductivity of the obtained conductive polymer solution is better, and the wafer resistance prepared by using the conductive polymer solution is lower.

The polar proton solution is a mixed solution of a polar organic solvent and water, and the polar organic solvent comprises an alcohol solvent, a ketone solvent, N-methylpyrrolidone (NMP) and other polar proton solvents commonly used in the field. The mass part of water in the polar proton solution in the conductive polymer solution is 40-70 parts.

The alcohol solvent comprises methanol, ethanol, butanol, isopropanol, glycerol, ethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol and the like; the ketone solvent comprises acetone, methyl ethyl ketone, methyl isobutyl ketone and the like.

By adjusting the solvent components, the dispersion stability of the modified polythiophene and the nano-graphite flake in the solvent, the wettability of the solvent to the wafer and the volatilization speed of the solvent can be improved. Preferably, the polar organic solvent is ethanol. The solvent is fast in volatilization speed, the conductive polymer solution is sprayed on the surface of the wafer and is not easy to condense, and the wettability to the wafer is better.

The modified polythiophene aqueous dispersion is an aqueous dispersion of poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid), wherein the average particle size of the poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid) is 50-100 nm, and the solid content in water is 0.5-2.0%. Preferably, the modified polythiophene aqueous dispersion is clevelos PH 1000 product of herly, germany.

The average particle diameter of the nano graphite sheets in the nano graphite sheet aqueous dispersion is 10-500 nm, and the solid content in water is 0.1-10%. The nano graphite sheets have good water dispersibility, are well dispersed and stabilized in polar proton solution, and the obtained conductive polymer solution is sprayed on a wafer to form a film, wherein the nano graphite sheets in the film are uniformly distributed and have good conductivity.

The dispersant is one or more of surfactants commonly used in the art, such as one or more of cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants.

The cationic surfactant comprises an amine salt type cationic surfactant, a quaternary ammonium salt type cationic surfactant, a cationic polymer surfactant and the like.

Further, the amine salt type cationic surfactant comprises octadecylamine hydrochloride, dioctadecyl amine hydrochloride, N, N-dimethyl octadecylamine hydrochloride, polyacrylamide hydrochloride and the like.

Further, the quaternary ammonium salt type cationic surfactant includes dioctadecyl dimethyl ammonium chloride, octadecyl dimethyl benzyl ammonium chloride, octadecyl amide dimethyl propyl ammonium chloride, octadecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide, dodecyl trimethyl ammonium chloride, dodecyl trimethyl ammonium bromide, dodecyl dimethyl benzyl ammonium chloride, oleamide methyl hydroxypropyl ammonium chloride, erucamide propyl trimethyl ammonium chloride, and the like.

Further, the cationic polymer surfactant comprises polyethyleneimine, polyvinylpyrrolidone, quaternized polyacrylamide and the like.

The anionic surfactant comprises sodium alkyl sulfate, sodium alkyl sulfonate, sodium alkyl ether sulfate, triethanolamine alkyl ether sulfate, ammonium alkyl ether sulfate, sodium alkyl ether phosphate, sodium fluoroalkyl carboxylate and the like.

The nonionic surfactant comprises polyoxyethylene alkyl ether, polyoxyethylene phenyl ether, polyoxyethylene alkyl ester, propylene glycol-propylene oxide copolymer, perfluoroalkyl ethylene oxide adduct, 2-ethylhexanol ethylene oxide adduct and the like.

The amphoteric surfactant comprises alkyl amino acetic acid betaine, alkyl amide acetic acid betaine, imidazole betaine and the like.

Because the surface of the nano graphite sheet contains a certain hydroxyl or carboxyl and presents weak electronegativity, the dispersing agent of the invention is preferably a cationic surfactant, and can neutralize the electronegativity of the nano graphite sheet, so that the dispersing agent can be dispersed in a solution more stably.

Further preferably, the dispersing agent is polyethyleneimine, and polyethyleneimine exists in water in the form of polymeric cations, so that all anionic substances can be neutralized or adsorbed, amino groups contained in molecular chains of polyethyleneimine can react with carboxyl groups to generate hydrogen bonds, react with carboxyl groups to generate ion bonds, and react with carbonyl groups to generate covalent bonds. The polyethyleneimine can have stronger interaction with the nano graphite sheet, and is beneficial to the dispersion of the nano graphite sheet in the aqueous solution.

The leveling agent is acrylic acid copolymer leveling agent, organic silicon leveling agent or fluorocarbon surfactant.

Preferably, the leveling agent is an acrylic copolymer leveling agent, and the product is commonly used as a solvent-based and water-based paint system, and is accumulated on the surface of the coating by means of a similar compatibility principle, so that the surface tension of a high-molecular conductive solution system is greatly reduced, and particularly the wettability of a substrate is improved, and shrinkage cavities are prevented.

Further preferably, the leveling agent is an ionic acrylate copolymer solution BYK381 of Pick Germany.

The wetting agent is an organosilicon gemini surfactant or an acetylenic diol gemini surfactant. Due to the surface tension of 7×10 of the conductive polymer solution ^-4 ～8×10 ^-4 N·cm ^-1 Slightly higher than the surface tension of the quartz wafer (about 7×10 ^-4 N·cm ^-1 ) Therefore, the conductive polymer solution has poor infiltration effect on the quartz wafer. The wetting agent is added, so that the surface tension of the conductive polymer solution can be reduced, the good infiltration of the conductive polymer solution to quartz crystals is promoted, surface defects such as shrinkage cavities or edges are prevented, and the fluidity, leveling property and adhesive force of the solution are improved.

Preferably, the wetting agent is an acetylenic diol gemini surfactant, which not only can reduce balance and dynamic surface tension, but also can obviously improve fluidity and leveling property, so that the wetting agent can easily enter the surface of a substrate which is difficult to wet, and the wetting performance of the conductive polymer solution on quartz wafers is improved.

Further preferably, the wetting agent is Dynol 607, a gas company of America.

Preferably, the dispersing agent is a cationic surfactant, the leveling agent is an acrylic copolymer leveling agent, and the wetting agent is an acetylenic diol gemini surfactant. Under the combination, the wettability, the fluidity and the fluidity of the conductive polymer solution are better.

Further preferably, the dispersing agent is polyethyleneimine, the leveling agent is BYK381, an ionic acrylate copolymer solution of Pick, germany, and the wetting agent is Dynol 607, a gas company of America. Under the combination, each performance of the conductive polymer solution is optimal.

When the conductive polymer solution for the crystal resonator is applied to the crystal resonator, the conductive polymer solution is coated on the surface of a wafer in a spray gun spraying mode.

Because the main component of the conductive polymer solution is water, the wetting effect of the water on the quartz wafer is poor, and water drops can be condensed on the surface of the quartz wafer in the spraying process, so that the surface of the coating is uneven. Besides adding flatting agent and wetting agent into the solution to improve the infiltration effect, the temperature of the quartz wafer is also increased to accelerate the quick volatilization of the spraying liquid, and the proper temperature range of the quartz wafer is 100-150 ℃, preferably 120 ℃.

Meanwhile, the solution is prevented from condensing into water drops on the surface of the quartz wafer as much as possible in the spraying process of the spray gun, so that the surface of the coating is uneven. If the surface of the wafer has liquid drops, the spraying should be stopped immediately, and the wafer is put into an oven with the temperature of 100-150 ℃ for heat treatment, so that the spraying liquid on the surface volatilizes to form a film; and then spraying is continued, and after the spraying is finished, the wafer is placed into an oven for 2-15 min at 100-150 ℃ to remove the solvent. And removing the template to obtain the quartz wafer for the resonator, the surface of which is coated with the conductive polymer electrode.

The wafer has the electrode with good conductivity, the surface resistance of the electrode can be as low as 232 omega, the crystal resonator prepared by taking the conductive polymer solution as the electrode can smoothly start vibration, the resonance frequency of the resonator can be adjusted between 3.99 MHz and 4.02MHz, and the conductive polymer solution is expected to replace metal silver to be applied to the field of crystal resonators.

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

(1) The nano-scale graphite with good water dispersibility is added into the modified polythiophene aqueous dispersion, so that the defect that the flatness of the conductive coating is affected by the micron-scale filler is overcome;

(2) The adopted nano graphite has good dispersibility in water, and the dispersing agent is added to ensure the dispersion stability of the nano graphite in the water solution;

(3) By adding the wetting agent and adjusting the solvent ratio, the conductive polymer solution is ensured to have good wettability and proper volatility on the wafer, and the surface regularity of the coating and the spraying efficiency are improved.

Detailed Description

The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. Modifications and equivalents will occur to those skilled in the art upon understanding the present teachings without departing from the spirit and scope of the present teachings.

The materials used in the following embodiments are all commercially available products. The modified polythiophene aqueous dispersion was Hericium clevelos pH 1000, germany, and the solid content was 1.0%; the nano graphite flake is produced by a certain manufacturer in China, the average grain diameter is between 10 and 100nm, and the solid content is 10 percent; the dispersing agent is polyethyleneimine, which is a general commercial product; the leveling agent is an ionic acrylate copolymer solution BYK381 of the German Pick company; the wetting agent is Dynol 607, an acetylene glycol gemini surfactant of America gas company.

Example 1

Preparing an ethanol aqueous solution, a modified polythiophene aqueous dispersion, a nano graphite flake aqueous dispersion, polyethyleneimine, BYK381 and Dynol 607 into a conductive polymer solution, wherein the mass ratio of each component is as follows: the water content is 40%, the ethanol content is 49.36%, the modified polythiophene aqueous dispersion is 10%, the nano-graphite sheet aqueous dispersion is 0.6%, the polyethyleneimine content is 0.02%, the BYK381 content is 0.01%, and the Dynol 607 content is 0.01%.

Before spraying, firstly placing a wafer on a specific template, heating the wafer to 120 ℃ in an oven, then taking out the wafer, spraying the prepared conductive polymer solution by a spray gun, keeping the wetting condition of the conductive polymer solution on the surface of the wafer at any time in the spraying process, immediately stopping spraying if liquid drops appear on the surface of the wafer, putting the wafer into the oven at 120 ℃ for heat treatment for 1min, taking out the wafer, and continuing spraying until 1.5g of the conductive polymer solution is sprayed on one side of the wafer. Then, 1.55g of a conductive polymer solution was sprayed on the other surface of the wafer in the same manner. After spraying was completed, the wafer was placed in an oven at 120 ℃ for 10min to remove the solvent. And finally, removing the template to obtain the quartz wafer for the resonator, the surface of which is coated with the conductive polymer electrode.

Examples 2 to 3

The electroconductive polymer solution prepared in example 1 was sprayed on the wafer surface according to the spraying process of example 1, and the spraying amount of the single-sided wafer was 2.5g (example 2), 5g (example 3), respectively.

Example 4

Preparing an ethanol aqueous solution, a modified polythiophene aqueous dispersion, a nano graphite flake aqueous dispersion, polyethyleneimine, BYK381 and Dynol 607 into a conductive polymer solution, wherein the mass ratio of each component is as follows: the water content is 50%, the ethanol content is 39.36%, the modified polythiophene aqueous dispersion is 9%, the nano-graphite sheet aqueous dispersion is 1.6%, the polyethyleneimine content is 0.02%, the BYK381 content is 0.01%, and the Dynol 607 content is 0.01%.

The electroconductive polymer solution prepared in this example was sprayed on the wafer surface according to the spraying process of example 1, and the spraying amount of the single-sided wafer was 2.5g.

Example 5

Preparing an ethanol aqueous solution, a modified polythiophene aqueous dispersion, a nano graphite flake aqueous dispersion, polyethyleneimine, BYK381 and Dynol 607 into a conductive polymer solution, wherein the mass ratio of each component is as follows: the water content is 70%, the ethanol content is 19.36%, the modified polythiophene aqueous dispersion is 8.5%, the nano-graphite sheet aqueous dispersion is 2.1%, the polyethyleneimine content is 0.02%, the BYK381 content is 0.01%, and the Dynol 607 content is 0.01%.

Comparative example 1

Preparing a conductive polymer solution from modified polythiophene aqueous dispersion, wherein the mass ratio of the modified polythiophene aqueous dispersion is 10% and the water is 90%. The electroconductive polymer solution prepared in this comparative example was sprayed on the wafer surface according to the spraying process of example 1, and the spraying amount of the single-sided wafer was 2.5g.

The amounts of each component in the conductive polymer solutions of examples 1 to 5 and comparative example 1 in terms of the ratio and the single-sided wafer spray coating amounts are summarized in Table 1.

TABLE 1 content of each component in conductive Polymer solution and Single-sided wafer spray coating amount

The wafers prepared in examples 1 to 5 and comparative example 1 were subjected to surface resistance and resonance frequency tests, electrode impedance was measured using an Agilent 34401A universal meter, and resonance frequencies of the crystals were measured using an E5100 analyzer and a 250B network analyzer, and the test results are shown in Table 2. As can be seen from the data in table 2, the surface resistance of the wafers prepared using the conductive polymer solutions of examples 1 to 5 decreased with the increase in the amount of spray coating; the content of nano graphite sheets in the conductive polymer solution system is increased, the content of modified polythiophene aqueous dispersion is reduced, the surface resistance of the wafer is further reduced, the minimum resistance can reach 232 omega, and the conductivity is excellent;

meanwhile, the wafer resistance of the conductive polymer solution containing only the modified polythiophene in comparative example 1 is 2349 omega, and the wafer surface resistance prepared in example 2 is 1592 omega, which shows that the addition of the nano graphite sheet can greatly improve the conductivity of the solution, the crystal resonator prepared by taking the conductive liquid as an electrode can smoothly start vibration, the resonance frequency of the resonator can be adjusted between 3.99-4.02 MHz, and the conductive polymer solution is expected to replace metal silver to be applied to the field of crystal resonators.

Table 2 wafer resonant frequency and surface resistance prepared in each example

Numbering device	Resonant frequency (Hz)	Surface resistance (Ohms)
			Example 1	4,023,493.00	3576.21
Example 2	4,016,154.10	1592.55
			Example 3	3,999,527.78	1098.80
Example 4	4,016,232.10	920.53
			Example 5	4,016,737.91	232.16
Comparative example 1	4,017,017.52	2349.22

Claims

1. The conductive polymer solution for the crystal resonator is characterized by comprising the following raw material components in parts by mass:

80 to 98.5 portions of polar proton solution;

1-10 parts of modified polythiophene aqueous dispersion;

0.1 to 3 parts of nano graphite sheet aqueous dispersion;

0.01 to 0.05 part of dispersing agent;

0.01 to 0.05 portion of leveling agent;

0.01 to 0.05 portion of wetting agent;

the modified polythiophene aqueous dispersion is an aqueous dispersion of poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid), wherein the average particle size of the poly (3, 4-ethylenedioxythiophene) -poly (styrenesulfonic acid) is 50-100 nm, and the mass content of the modified polythiophene aqueous dispersion in water is 0.5-2.0%; the mass ratio of the modified polythiophene aqueous dispersion to the nano graphite flake aqueous dispersion is 100:30-100:5;

the dispersing agent is polyethyleneimine;

the polar proton solution is a mixed solution of a polar organic solvent and water, wherein the polar organic solvent comprises one or more of methanol, ethanol and acetone.

2. The electroconductive polymer solution for a crystal resonator according to claim 1, wherein the aqueous dispersion of nano graphite flakes is an aqueous dispersion of nano graphite flakes having an average particle diameter of 10 to 500nm and a mass content in water of 0.1 to 10%.

3. The electroconductive polymer solution for a crystal resonator according to claim 1, wherein the leveling agent is an acrylic copolymer leveling agent, an organosilicon leveling agent or a fluorocarbon surfactant.

4. The electroconductive polymer solution for a crystal resonator according to claim 1, wherein the wetting agent is an organosilicon gemini surfactant or an acetylenic diol gemini surfactant.

5. The electroconductive polymer solution for a crystal resonator according to claim 1, wherein the leveling agent is an acrylic copolymer leveling agent, and the wetting agent is an acetylenic diol gemini surfactant.

6. Use of a conductive polymer solution for a crystal resonator according to any one of claims 1 to 5 in a crystal resonator, characterized in that the conductive polymer solution according to any one of claims 1 to 5 is applied to the wafer surface by spraying with a spray gun.