阅读说明：本技术 纳米复合导电粘附水凝胶及其制备方法与应用 (Nano composite conductive adhesive hydrogel and preparation method and application thereof ) 是由 陈莉 邓泽鹏 何洋 江鹏 王彦杰 于 2019-10-09 设计创作，主要内容包括：本发明提出一种纳米复合导电粘附水凝胶及其制备方法与应用,涉及柔性传感器领域。所述水凝胶包括下述步骤：(a)将阳离子单体、光引发剂、阴离子组分、磺化MXene纳米粒子、水,混合,得前驱体溶液；(b)将上述前驱体溶液脱泡；(c)采用紫外光照射步骤(b)所得前驱体溶液,引发阳离子单体聚合,产生的阳离子单体聚合物与阴离子组分、纳米粒子共同作用形成水凝胶。本发明所得水凝胶不仅能够极好的粘附于各种复杂的表面,具有高拉伸、可自愈等性能,同时具有导电性能和光热转化性能等,可应用于柔性传感器及其他领域。(The invention provides a nano composite conductive adhesive hydrogel and a preparation method and application thereof, and relates to the field of flexible sensors. The hydrogel comprises the following steps: (a) mixing a cationic monomer, a photoinitiator, an anionic component, sulfonated MXene nanoparticles and water to obtain a precursor solution; (b) defoaming the precursor solution; (c) and (c) irradiating the precursor solution obtained in the step (b) by using ultraviolet light to initiate the polymerization of the cationic monomer, and allowing the generated cationic monomer polymer to act together with the anionic component and the nano particles to form the hydrogel. The hydrogel obtained by the invention can be excellently adhered to various complex surfaces, has the performances of high stretching, self-healing and the like, has the performances of conductivity, photothermal conversion and the like, and can be applied to flexible sensors and other fields.)

1. A preparation method of a nano-composite conductive adhesive hydrogel is characterized by comprising the following steps:

(a) mixing a cationic monomer, a photoinitiator, an anionic component, sulfonated MXene nanoparticles and water to obtain a precursor solution;

(b) defoaming the precursor solution;

(c) irradiating the precursor solution obtained in the step (b) by using ultraviolet light to initiate cationic monomer polymerization, and allowing the generated cationic monomer polymer, an anionic component and sulfonated MXene nanoparticles to act together to form hydrogel;

wherein the anionic component comprises a glycosaminoglycan and derivatives thereof.

2. The method of claim 1,

the anion component comprises one or more of chondroitin sulfate, keratan sulfate, dermatan sulfate and heparin.

3. The method of claim 1,

in the step (a), the cationic monomer is a quaternary ammonium salt type cationic monomer;

preferably, the quaternary ammonium salt type cationic monomer includes one of acryloyloxyethyltrimethyl ammonium chloride, [3- (methacrylamido) propyl ] trimethylammonium chloride, and (3-acrylamidopropyl) trimethylammonium chloride.

4. The method according to any one of claims 1 to 3,

in the step (a), the molar ratio of the charged cationic monomer to the charged anionic component is 1: (0.05-1.25); preferably, the molar ratio of the charged cationic monomer to the charged anionic component is 1: (0.1-0.5);

in the step (a), the molar ratio of the cationic monomer to the photoinitiator is 1: (0.1% -0.5%);

the photoinitiator is ketoglutaric acid.

5. The method of claim 1,

in the step (a), the addition amount of the sulfonated MXene nano particles is 0.1-0.3 wt% of the precursor solution;

the preparation method of the sulfonated MXene nano particles comprises the following steps:

(a1)Na⁺preparation of intercalated Mxene: adding titanium aluminum carbide powder into etching liquid for etching, centrifuging and washing to obtain MXene suspension, adding sodium hydroxide solution, stirring, washing and centrifuging to obtain Na⁺Intercalation MXene slurry;

(a2) synthesis of sulfanilic acid diazonium salt: suspending sulfanilic acid in deionized water, adding dilute hydrochloric acid under an ice bath condition, stirring, dropwise adding a sodium nitrite solution into the suspension, and reacting to obtain sulfanilic acid diazonium salt;

(a3) sulfonation modification of MXene: dropwise adding the sulfanilic acid diazoate solution obtained in the step (a2) into Na described in the step (a1) under ice bath conditions⁺And (3) intercalating MXene slurry, reacting, centrifuging, filtering, washing and ultrasonically treating the obtained mixture solution, and freeze-drying to obtain the sulfonated MXene nano-particles.

6. The method of claim 1,

in the step (a), the concentration of the charges carried by the precursor solution is 1.5-3.5 mol/L; preferably, the concentration of the charges carried by the precursor solution is 2-3 mol/L; more preferably, the concentration of the charge carried by the precursor solution is 2.5 mol/L.

7. The method of claim 1,

the step (b) is specifically as follows: carrying out ultrasonic treatment on the precursor solution obtained in the step (a) to remove large bubbles, and then carrying out vacuum treatment and standing to remove micro bubbles;

wherein the ultrasonic treatment time is 0.5-3 h; the vacuum treatment is vacuum pumping for 0.5 to 1.5 hours under the pressure of-0.1 MPa;

in the step (c), the light source wavelength of the ultraviolet light is 365nm, the power is 300W, and the illumination time is 9-13 h.

8. A nanocomposite, electrically conductive, adherent hydrogel prepared by the method of any one of claims 1 to 7.

9. Use of the nanocomposite, electrically conductive adhesive hydrogel according to claim 8 for the preparation of a sensor for strain sensing, humidity sensing.

10. Use of the nanocomposite conductive adhesive hydrogel according to claim 8 for preparing a photothermal conversion material.

Technical Field

The invention relates to the field of flexible sensors, in particular to a nano composite conductive adhesive hydrogel and a preparation method and application thereof.

Background

With the development of flexible materials and electronic technology, wearable flexible sensors have attracted great attention from researchers due to their superior characteristics that can be used to capture and monitor various activities of humans.

The sensitive materials of the flexible strain sensor researched at present mainly comprise two types: one kind is a sensor using conductive materials such as silver, carbon tubes, graphene and the like as strain sensitive materials; the other is a sensor using semiconductor material as strain sensitive material. Both have been developed to varying degrees in the field of flexible sensors.

Luo et al (Luo C, Jia J, Gong Y, et al. high Sensitive, Durable, and multifunctional Sensor implanted by Spider [ J ]. ACS Applied Materials & Interfaces,2017: acsami.7b02988.) adopt Spider silk-like SWNTs thin films with a corrugated structure as conductive Materials, and ion-sputter a layer of nano gold thin film as Sensitive Materials, and assemble a SWNTs/nano gold composite thin film flexible Sensor capable of detecting strain and temperature simultaneously. The high-sensitivity and multifunctional sensor can be applied to the fields of intelligent electronic devices and human-computer interaction.

The PANI/PDMS composite film Flexible strain sensor is prepared by using a Flexible strain sensor with high performance based on PANI/PDMS films [ J ] and PDMS as an elastic layer, and has excellent cycling stability.

It can be seen that the above-mentioned flexible sensors all have good sensitivity, however, ideal wearable flexible sensors often need to have high stretchability and adhesiveness to irregular surfaces, while the prior art flexible sensors are limited by the base material, have poor deformability, cannot spontaneously adhere and can be stretched greatly, and the like.

Disclosure of Invention

The invention provides a nano composite conductive adhesive hydrogel and a preparation method and application thereof. By designing and regulating the internal structure of the hydrogel, the obtained hydrogel can be excellently adhered to various complex surfaces, has the performances of high stretching, self-healing and the like, has conductivity, can be used for preparing a sensor for strain sensing, humidity sensing and the like, has photothermal conversion performance, and further expands the application range of the hydrogel.

The invention provides a preparation method of a nano composite conductive adhesive hydrogel, which comprises the following steps:

(a) mixing a cationic monomer, a photoinitiator, an anionic component, sulfonated MXene nanoparticles and water to obtain a precursor solution;

(b) defoaming the precursor solution;

(c) irradiating the precursor solution obtained in the step (b) by using ultraviolet light to initiate cationic monomer polymerization, and allowing the generated cationic monomer polymer, an anionic component and sulfonated MXene nanoparticles to act together to form hydrogel;

wherein the anionic component comprises a glycosaminoglycan and derivatives thereof.

Further, the anion component comprises one or more of chondroitin sulfate, keratan sulfate, dermatan sulfate and heparin.

Further, in the step (a), the cationic monomer is a quaternary ammonium salt type cationic monomer.

Preferably, the quaternary ammonium salt type cationic monomer includes one of acryloyloxyethyltrimethyl ammonium chloride, [3- (methacrylamido) propyl ] trimethylammonium chloride, and (3-acrylamidopropyl) trimethylammonium chloride.

Further, in step (a), the molar ratio of the charged cationic monomer to the charged anionic component is 1: (0.05-1.25); preferably, the molar ratio of charged cationic monomer to charged anionic component is 1: (0.1-0.5).

Further, in the step (a), the molar ratio of the cationic monomer to the photoinitiator is 1: (0.1% -0.5%);

the photoinitiator is ketoglutaric acid.

Further, in the step (a), the addition amount of the sulfonated MXene nano particles is 0.1-0.3 wt% of the precursor solution;

the preparation method of the sulfonated MXene nano particles comprises the following steps:

(a1)Na⁺preparation of intercalated Mxene: adding titanium aluminum carbide powder into etching liquid for etching, centrifuging and washing to obtain MXene suspension, adding sodium hydroxide solution, stirring, washing and centrifuging to obtain Na⁺Intercalation MXene slurry;

(a2) synthesis of sulfanilic acid diazonium salt: suspending sulfanilic acid in deionized water, adding dilute hydrochloric acid under an ice bath condition, stirring, dropwise adding a sodium nitrite solution into the suspension, and reacting to obtain sulfanilic acid diazonium salt;

(a3) sulfonation modification of MXene: dropwise adding the sulfanilic acid diazoate solution obtained in the step (a2) to Na in the step (a1) under ice bath conditions⁺And (3) intercalating MXene slurry, reacting, centrifuging, filtering, washing and ultrasonically treating the obtained mixture solution, and freeze-drying to obtain the sulfonated MXene nano-particles.

Further, in the step (a), the concentration of the charges carried by the precursor solution is 1.5-3.5 mol/L; preferably, the concentration of the charges carried by the precursor solution is 2-3 mol/L; more preferably, the concentration of the charge carried by the precursor solution is 2.5 mol/L.

Further, the step (b) is specifically as follows: carrying out ultrasonic treatment on the precursor solution obtained in the step (a) to remove large bubbles, and then carrying out vacuum treatment and standing to remove micro bubbles;

wherein the ultrasonic treatment time is 0.5-3 h; vacuum-treating under-0.1 MPa for 0.5-1.5 hr;

in the step (c), the wavelength of the light source of the ultraviolet light is 365nm, the power is 300W, and the illumination time is 9-13 h.

The invention provides the nano-composite conductive adhesive hydrogel prepared by the method.

The invention provides application of the nano-composite conductive adhesive hydrogel in preparation of sensors, and the sensors can be used for strain sensing and humidity sensing.

The invention provides application of the nano-composite conductive adhesive hydrogel in preparation of a photo-thermal conversion material.

The invention has the following beneficial effects:

according to the invention, cationic monomers and photoinitiators thereof, anionic components and sulfonated MXene nanoparticles are added, under the initiation of ultraviolet light, the cationic monomers are polymerized to form long-chain cationic polymers, and the short-chain polymer anionic components can be inserted into gaps of the long-chain cationic polymers which are mutually entangled, so that the regulation and control of the gel viscoelasticity are realized, and the gel texture is soft to adapt to various complex solid surfaces; the sulfonated MXene nano particles serve as physical cross-linking points in the gel, are negatively charged and can act with a cationic polymer with positive charge, so that the stability and the adhesive strength of the hydrogel are further improved, and the reversibility of electrostatic interaction among the components enables the adhesive gel to have self-healing performance.

In addition, due to the addition of the sulfonated MXene nanoparticles with the conductivity, the hydrogel can be endowed with the conductivity, and the sulfonated MXene nanoparticles are combined with the specific three-dimensional network structure, so that the structural characteristics of good tensile deformation performance of the three-dimensional network and the like are fully exerted, the gel can be used for preparing a sensor for strain sensing, humidity sensing and the like, meanwhile, the gel has the photothermal conversion performance, and the application range of the hydrogel is further expanded.

Drawings

FIG. 1 is a schematic view of a lap shear strength test;

fig. 2 is a schematic diagram of the adhesion strength of the nanocomposite conductive adhesive hydrogel to different substances, wherein fig. 2(a) shows the adhesion strength of the conductive adhesive hydrogel to different inorganic substances with different MXene addition amounts, and fig. 2(B) shows the adhesion strength of the conductive adhesive hydrogel to different organic substances with different MXene addition amounts;

FIG. 3 is a digital photograph showing the self-healing performance of the nanocomposite conductive adhesive hydrogel;

fig. 4 is a rheological representation diagram of the self-healing performance of the nanocomposite conductive adhesive hydrogel, wherein fig. 4(a) is a rheological representation diagram of the self-healing performance of the gel when the addition amount of the sulfonated MXene is 0.1 wt%, fig. 4(B) is a rheological representation diagram of the self-healing performance of the gel when the addition amount of the sulfonated MXene is 0.2 wt%, and fig. 4(C) is a rheological representation diagram of the self-healing performance of the gel when the addition amount of the sulfonated MXene is 0.3 wt%;

FIG. 5 is a schematic diagram of the application of the nanocomposite conductive adhesive hydrogel in a strain sensor, wherein FIG. 5(A) shows the resistance change of the conductive adhesive hydrogel under different bending angles of a finger, and FIGS. 5(B), 5(C), 5(D) and 5(E) show the resistance change of the conductive adhesive gel during continuous motion of the finger, wrist, elbow and back neck, respectively;

FIG. 6 is a schematic diagram of a nanocomposite conductive adhesive hydrogel applied in different humidity sensing applications;

fig. 7 is a schematic view of photothermal conversion application of the nanocomposite conductive adhesive hydrogel, wherein fig. 7(a) and 7(B) are an infrared thermograph and a specific temperature variation graph of the conductive composite gel with different nanoparticle addition amounts under irradiation of a xenon light source, respectively;

FIG. 8 is a drawing of hydrogel tensile property test, wherein FIG. 8(A) is a schematic diagram of a nanocomposite conductive adhesive hydrogel before stretching; fig. 8(B) is a schematic diagram of the nanocomposite conductive adhesive hydrogel after stretching.

Detailed Description

The invention is described below by means of specific embodiments. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. In addition, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications in the components and amounts of the materials used in these embodiments can be made without departing from the spirit and scope of the invention.

The polyion compound gel is hydrogel formed by polymers with opposite charges through electrostatic interaction, and has attracted extensive attention in the fields of high-strength gel and intelligent response gel due to the characteristics of excellent mechanical property and physical crosslinking. However, the polyion composite hydrogel in the prior art is often prepared by a two-step method (sequential and separate polymerization of cationic monomers and anionic monomers), which is relatively complicated, and the high-concentration precursor solution often causes the gel to have a relatively hard texture, which is not favorable for the application in the adhesion field.

According to the embodiment of the invention, by designing and regulating the internal structure of the gel, the polyion composite hydrogel is prepared by adopting a one-step method (cationic monomer homopolymerization and electrostatic combination with short-chain anionic components), and meanwhile, conductive inorganic nanoparticles are introduced into a gel system with a specific proportion, so that the conductive adhesive hydrogel with excellent performance is obtained.

The embodiment of the invention provides a preparation method of a nano composite conductive adhesive hydrogel, which comprises the following steps:

(a) mixing a cationic monomer, a photoinitiator, an anionic component, sulfonated MXene nanoparticles and water to obtain a precursor solution;

(b) defoaming the precursor solution;

(c) irradiating the precursor solution obtained in the step (b) by using ultraviolet light to initiate the polymerization of a cationic monomer, and allowing the generated cationic monomer polymer to act together with an anionic component and nano particles to form hydrogel;

wherein, in the step (a), the anionic component comprises glycosaminoglycan and derivatives thereof.

According to the embodiment of the invention, a cationic monomer and a photoinitiator thereof, an anionic component and sulfonated MXene nanoparticles are added, under the initiation of ultraviolet light, the cationic monomer is polymerized to form a long-chain cationic polymer, the anionic component and the sulfonated MXene nanoparticles do not react, then, the long chains of the cationic polymer are intertwined with each other, and form an interpenetrating three-dimensional network structure through electrostatic interaction, hydrogen bond interaction and the like with the anionic component and the nanoparticles.

In the three-dimensional network structure, the anion component of the short-chain polymer can be inserted into the gap of the long-chain polymer with positive electricity, so that the regulation and control of the viscoelasticity performance of the gel are realized, the gel is soft to adapt to various complex solid surfaces, the sulfonated MXene nano particles serve as physical cross-linking points in the gel, the sulfonated MXene nano particles are negatively charged and can act with the cationic monomer polymer with positive electricity, the stability and the adhesive strength of the hydrogel are further improved, and the reversibility of the electrostatic action among the components enables the adhesive gel to have the self-healing performance.

In addition, due to the addition of the sulfonated MXene nanoparticles with the conductivity, the hydrogel can be endowed with the conductivity, and the sulfonated MXene nanoparticles are combined with the specific three-dimensional network structure, so that the structural characteristics of good tensile deformation performance of the three-dimensional network and the like are fully exerted, the gel can be used for preparing a sensor for strain sensing, humidity sensing and the like, and meanwhile, the gel has the photothermal conversion performance.

Therefore, the hydrogel can be excellently adhered to various complex surfaces, has the performances of high stretching, self-healing and the like, has conductivity, can be used for preparing a sensor for strain sensing, humidity sensing and the like, has photothermal conversion performance, and greatly widens the application range of the hydrogel.

The preparation method of the hydrogel is simple in process, does not need special equipment, is mild in condition, is safe and nontoxic in raw materials, does not need to add a crosslinking agent, simplifies a gel system, and avoids the situation that the unreacted crosslinking agent is remained in the gel to cause the gel to be toxic.

The glycosaminoglycan and the derivatives thereof selected by the embodiment of the invention are short-chain polymers, and the introduction of the short-chain polymer chain can reduce the modulus of the gel under the condition of not reducing the concentration of the gel liquid; meanwhile, the glycosaminoglycan has viscosity, is taken from animal cartilage, has good biocompatibility, and can improve the viscosity and the biocompatibility of the gel.

In an embodiment of the present invention, the anionic component comprises glycosaminoglycans and derivatives thereof.

Preferably, the glycosaminoglycan comprises one or more of chondroitin sulfate, keratan sulfate, dermatan sulfate, and heparin.

Specifically, the derivative of glycosaminoglycan may be a salt corresponding to glycosaminoglycan, such as a salt of chondroitin sulfate, a salt of keratan sulfate, a salt of dermatan sulfate, a salt of heparin, more specifically, chondroitin sulfate or a calcium salt of chondroitin sulfate, keratan sulfate or a sodium salt of keratan sulfate, and the like.

In one embodiment of the present invention, in the step (a), the cationic monomer is a quaternary ammonium salt type cationic monomer. Preferably, the quaternary ammonium salt type cationic monomer includes one of acryloyloxyethyltrimethyl ammonium chloride, [3- (methacrylamido) propyl ] trimethylammonium chloride, and (3-acrylamidopropyl) trimethylammonium chloride.

In one embodiment of the present invention, the molar ratio of the charged cationic monomer to the charged anionic component is 1: (0.05-1.25). Specifically, the ratio of 1: 0.1, 1: 0.25, 1: 0.5, 1: 0.75, 1: 1.0, 1: 1.25, etc. In the embodiment of the invention, each repeating disaccharide unit structure in the anion component such as chondroitin sulfate has at least one negative charge, and in the high-concentration system, each mole of repeating disaccharide unit structure in the anion component has one mole of negative charges, so that the error caused by the fact that the charge of each individual disaccharide unit structure is more than one is negligible.

Thus, the cationic monomer and the anionic component are used in a molar ratio of 1: (0.05-1.25). By the number of moles of the charge of the anionic component, the number of moles of the disaccharide unit structure in the anionic component can be obtained, and thus the mass of the disaccharide unit structure, that is, the mass of the anionic component can be calculated. And 1mol of the cationic monomer has a charge amount of 1 mol.