阅读说明：本技术 高介电常数复合弹性体及其制备方法和柔性设备 (High dielectric constant composite elastomer, preparation method thereof and flexible equipment ) 是由 朱世平 张长庚 张祺 于 2021-08-25 设计创作，主要内容包括：本申请提供一种高介电常数复合弹性体及其制备方法和柔性设备,涉及材料领域。高介电常数复合弹性体,其原料包括弹性体基体和填充物,所述填充物包括深共熔溶剂,所述弹性体基体不与所述深共熔溶剂互溶；所述深共熔溶剂由氢键供体和氢键受体通过氢键作用结合得到。高介电常数复合弹性体的制备方法,包括：将所述原料混合、加热固化,得到所述高介电常数复合弹性体。柔性设备,其原料包括所述的高介电常数复合弹性体。本申请提供的高介电常数复合弹性体,兼具高介电常数、低介电损耗和低弹性模量,是一种非常适合大规模工业化生产的介电复合弹性体。(The application provides a high-dielectric-constant composite elastomer, a preparation method thereof and flexible equipment, and relates to the field of materials. The high dielectric constant composite elastomer comprises raw materials of an elastomer matrix and a filler, wherein the filler comprises a deep eutectic solvent, and the elastomer matrix is not mutually soluble with the deep eutectic solvent; the deep eutectic solvent is obtained by combining a hydrogen bond donor and a hydrogen bond acceptor through hydrogen bond action. The preparation method of the high dielectric constant composite elastomer comprises the following steps: and mixing the raw materials, heating and curing to obtain the high dielectric constant composite elastomer. The raw material of the flexible device comprises the high dielectric constant composite elastomer. The high dielectric constant composite elastomer provided by the application has high dielectric constant, low dielectric loss and low elastic modulus, and is a dielectric composite elastomer which is very suitable for large-scale industrial production.)

1. The composite elastomer with high dielectric constant is characterized in that raw materials comprise an elastomer matrix and a filler, wherein the filler comprises a deep eutectic solvent, and the elastomer matrix is not mutually soluble in the deep eutectic solvent;

the deep eutectic solvent is obtained by combining a hydrogen bond donor and a hydrogen bond acceptor through hydrogen bond action.

2. The high dielectric constant composite elastomer of claim 1, wherein the filler comprises 5% to 40% of the total volume of the raw material.

3. The high dielectric constant composite elastomer of claim 1, wherein the elastomer matrix comprises polydimethylsiloxane.

4. The composite elastomer with high dielectric constant as claimed in claim 1, wherein the hydrogen bond acceptor comprises one or more of lithium bistrifluoromethanesulfonylimide, metal chloride salt, and quaternary ammonium salt, and the hydrogen bond donor comprises urea and/or ethylene glycol.

5. The high dielectric constant composite elastomer of claim 4, wherein the hydrogen bond acceptor is lithium bistrifluoromethanesulfonylimide and the hydrogen bond donor is urea; the molar ratio of the urea to the lithium bis (trifluoromethane sulfonyl) imide is (2.3-4): 1.

6. the high dielectric constant composite elastomer of any one of claims 1 to 5, wherein the deep eutectic solvent has a melting point equal to or lower than room temperature.

7. A method for preparing the high dielectric constant composite elastomer according to any one of claims 1 to 6, comprising:

and mixing the raw materials, heating and curing to obtain the high dielectric constant composite elastomer.

8. The preparation method according to claim 7, wherein the temperature for heating and curing is 50-90 ℃ and the time is 2-4 h.

9. The method according to claim 7 or 8, wherein the method for preparing the deep eutectic solvent comprises:

mixing the hydrogen bond donor and the hydrogen bond acceptor.

10. A flexible device characterized in that its raw material comprises the high dielectric constant composite elastomer according to claims 1 to 6.

Technical Field

The application relates to the field of materials, in particular to a high-dielectric-constant composite elastomer, a preparation method thereof and flexible equipment.

Background

The dielectric elastomer is one of the most representative polymer materials, has good stretchability and optical transparency while having the insulating property of the dielectric material, and has wide application prospects in the fields of flexible electronics, soft robots, touch equipment and the like. In practical applications, the main references for evaluating the performance of dielectric materials are relative dielectric constant and dielectric loss. Electrical devices such as sensors, drivers, and light emitting devices based on dielectric elastomers often require functional materials with high dielectric constants to achieve the objectives of high sensitivity and low driving voltage. Therefore, the dielectric elastomer with high dielectric constant has very large application market in the fields of intelligent sensing, energy storage, microelectronic manufacturing and the like.

The relative dielectric constant of conventional homogeneous dielectric elastomers is generally low, and in order to increase the relative dielectric constant of the material, the addition of fillers to the elastomer matrix to prepare composite materials with significant space charge effects is the most common and effective means. Until now, researchers at home and abroad have compounded hard conductive or high dielectric materials such as metal particles, graphene, carbon nanotubes, perovskite ceramics and the like with an elastomer matrix to successfully prepare a composite dielectric elastomer with a high dielectric constant. However, the mechanical properties of the filler are greatly different from those of the elastomer matrix, so that the stretchability of the prepared composite material is greatly reduced, and the long-term application is not facilitated. The above problems can be effectively solved by replacing the hard material with a conductive liquid such as liquid metal, salt solution and ionic liquid. However, the liquid metal is difficult to be uniformly dispersed in the elastomer matrix, and easily seeps out of the composite material to destroy the stability; aqueous and organic salt solutions are volatile and do not produce long-term effective materials; the ionic liquid has high cost and complex purification process, and the internal impurities easily cause the incomplete curing of the elastomer, so the ionic liquid cannot adapt to the large-scale industrial production of the composite material.

Disclosure of Invention

The present application aims to provide a high dielectric constant composite elastomer, a preparation method thereof and a flexible device, so as to solve the above problems.

In order to achieve the purpose, the following technical scheme is adopted in the application:

the raw materials of the high dielectric constant composite elastomer comprise an elastomer matrix and a filler, wherein the filler comprises a deep eutectic solvent, and the elastomer matrix is not mutually soluble with the deep eutectic solvent;

the deep eutectic solvent is obtained by combining a hydrogen bond donor and a hydrogen bond acceptor through hydrogen bond action.

Preferably, the filler accounts for 5% -40% of the total volume of the raw materials.

Preferably, the elastomeric matrix comprises polydimethylsiloxane.

Preferably, the hydrogen bond acceptor comprises one or more of lithium bistrifluoromethanesulfonylimide, metal chloride salt and quaternary ammonium salt, and the hydrogen bond donor comprises urea and/or ethylene glycol.

Preferably, the hydrogen bond acceptor is lithium bistrifluoromethanesulfonylimide, and the hydrogen bond donor is urea; the molar ratio of the urea to the lithium bis (trifluoromethane sulfonyl) imide is (2.3-4): 1.

preferably, the melting point of the deep eutectic solvent is equal to or less than room temperature.

The application also provides a preparation method of the high dielectric constant composite elastomer, which comprises the following steps:

and mixing the raw materials, heating and curing to obtain the high dielectric constant composite elastomer.

Preferably, the temperature for heating and curing is 50-90 ℃ and the time is 2-4 h.

Preferably, the preparation method of the deep eutectic solvent comprises the following steps:

mixing the hydrogen bond donor and the hydrogen bond acceptor.

The application also provides a flexible device, and the raw material of the flexible device comprises the high dielectric constant composite elastomer.

Compared with the prior art, the beneficial effect of this application includes:

according to the high dielectric constant composite elastomer, the deep eutectic solvent is used as a filler to be matched with the elastomer substrate, and the prepared composite material has the advantages of high dielectric constant, low dielectric loss and low elastic modulus, and is a dielectric composite elastomer which is very suitable for large-scale industrial production; the deep eutectic solvent is obtained by combining the hydrogen bond donor and the hydrogen bond acceptor through the action of hydrogen bonds, no additional purification is needed, and the raw material cost is low.

The preparation method of the high-dielectric-constant composite elastomer is simple to operate, low in cost, 100% in product conversion rate and suitable for industrial production.

The high dielectric constant composite elastomer provided by the application can be widely applied to various flexible devices, such as flexible electronics, soft robots, touch devices and the like.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments are briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of the present application.

FIG. 1 is a photograph of the high dielectric constant composite elastomer obtained in examples 1 to 4;

FIG. 2 is a diagram showing the dielectric constant spectra of the high dielectric constant composite elastomers obtained in examples 1 to 4;

FIG. 3 is a spectrum of dielectric constant of the composite elastomer obtained in comparative example 1.

Detailed Description

The terms as used herein:

"prepared from … …" is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of … …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of … …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when the range "1 ~ 5" is disclosed, the ranges described should be construed to include the ranges "1 ~ 4", "1 ~ 3", "1 ~ 2 and 4 ~ 5", "1 ~ 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

In these examples, the parts and percentages are by mass unless otherwise indicated.

"part by mass" means a basic unit of measure indicating a mass ratio of a plurality of components, and 1 part may represent any unit mass, for example, 1g or 2.689 g. If we say that the part by mass of the component A is a part by mass and the part by mass of the component B is B part by mass, the ratio of the part by mass of the component A to the part by mass of the component B is a: b. alternatively, the mass of the A component is aK and the mass of the B component is bK (K is an arbitrary number, and represents a multiple factor). It is unmistakable that, unlike the parts by mass, the sum of the parts by mass of all the components is not limited to 100 parts.

"and/or" is used to indicate that one or both of the illustrated conditions may occur, e.g., a and/or B includes (a and B) and (a or B).

The raw materials of the high dielectric constant composite elastomer comprise an elastomer matrix and a filler, wherein the filler comprises a deep eutectic solvent, and the elastomer matrix is not mutually soluble with the deep eutectic solvent;

the deep eutectic solvent is obtained by combining a hydrogen bond donor and a hydrogen bond acceptor through hydrogen bond action.

The deep eutectic solvent is a new ionic conductive liquid, has the advantages of low cost, high transparency, high conductivity and the like, and is simple in preparation method and environment-friendly. The liquid deep eutectic solvent with the melting point far lower than that of the original component can be obtained by mixing the hydrogen bond donor and the hydrogen bond acceptor with high melting point according to a certain molar ratio, the product conversion rate is 100%, no additional purification step is needed, the cost of the used raw materials is low, and the advantages enable the deep eutectic solvent to be very suitable for large-scale industrial production.

In the obtained high dielectric constant composite elastomer material, the deep eutectic solvent as the filler is uniformly dispersed in the elastomer matrix in the form of micron-sized droplets, and the charge accumulation of a two-phase interface is caused due to the large difference between the conductivity of the filler and the elastomer matrix, so that the filler can be equivalent to a single micro capacitor, and the dielectric constant of the composite material is improved; and the deep eutectic solvent has high fluidity and good dispersibility in an elastomer matrix, so that the prepared composite material has low dielectric loss and elastic modulus.

In an alternative embodiment, the filler comprises 5% to 40% of the total volume of the feedstock.

Optionally, the proportion of the filler to the total volume of the feedstock may be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% or any value between 5% and 40%.

In an alternative embodiment, the elastomeric matrix comprises polydimethylsiloxane.

In an alternative embodiment, the hydrogen bond acceptor comprises one or more of lithium bistrifluoromethanesulfonylimide, metal chloride salts, quaternary ammonium salts, and the hydrogen bond donor comprises urea and/or ethylene glycol.

In an alternative embodiment, the hydrogen bond acceptor is lithium bistrifluoromethanesulfonylimide and the hydrogen bond donor is urea; the molar ratio of the urea to the lithium bis (trifluoromethane sulfonyl) imide is (2.3-4): 1.

in an alternative embodiment, the melting point of the deep eutectic solvent is equal to or less than room temperature.

The molar ratio of hydrogen bond acceptor to hydrogen bond donor is chosen as follows: the melting point of the deep eutectic solvent obtained by mixing is less than or equal to room temperature.

Here, the room temperature is 25 ℃.

Optionally, the molar ratio of the urea to the lithium bis (trifluoromethanesulfonyl) imide salt may be 2.3: 1. 2.5: 1. 3: 1. 3.5: 1. 4: 1 or (2.3-4): 1, or any value between.

The application also provides a preparation method of the high dielectric constant composite elastomer, which comprises the following steps:

and mixing the raw materials, heating and curing to obtain the high dielectric constant composite elastomer.

In an alternative embodiment, the temperature for heat curing is 50 ℃ to 90 ℃ for 2h to 4 h.

The crosslinking reaction of the polymer chain occurs during the curing process, so as to prepare the stretchable elastomer which is insoluble, infusible, stable in size and can not be molded and formed. The time required for curing needs to be considered when the curing temperature is selected, and when the temperature is too low, the time required for curing is long, so that the emulsion structure is unstable; when the temperature is too high, the time required for curing is short, and the operation is difficult. The curing temperature is within the range of 50-90 ℃, the curing time is reasonable, the process is simple and easy to control, and the product has stable properties.

Optionally, the temperature of the heating curing may be any value between 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ or 50 ℃ to 90 ℃, and the time may be any value between 2h, 3h, 4h or 2h to 4 h.

In an alternative embodiment, the method for preparing the deep eutectic solvent comprises:

mixing the hydrogen bond donor and the hydrogen bond acceptor.

The application also provides a flexible device, and the raw material of the flexible device comprises the high dielectric constant composite elastomer.

Embodiments of the present application will be described in detail below with reference to specific examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

Example 1

The embodiment provides a high dielectric constant composite elastomer, which comprises raw materials of a deep eutectic solvent and an elastomer matrix, wherein the deep eutectic solvent is urea (hydrogen bond donor)/lithium bistrifluoromethanesulfonylimide (hydrogen bond acceptor), and the molar ratio is 3: 1, the elastomer matrix is polydimethylsiloxane, and the deep eutectic solvent accounts for 30% of the total volume of the raw materials of the high dielectric constant composite elastomer.

The preparation method of the high dielectric constant composite elastomer comprises the following steps:

(1) fully mixing urea and lithium bistrifluoromethanesulfonylimide, standing, and obtaining a completely clear and transparent deep eutectic solvent when the solid completely disappears;

(2) mixing the deep eutectic solvent obtained in the step (1) with an elastomer substrate, and fully stirring to obtain uniform opaque emulsion which is a precursor solution of the high-dielectric-constant composite elastomer;

(3) curing the precursor solution obtained in the step (2) by a thermal curing method, wherein the thermal curing condition is 60 ℃, and the curing time is 4 hours;

(4) and (4) obtaining the high dielectric constant composite elastomer after the reaction in the step (3) is finished.

Example 2

The embodiment provides a high dielectric constant composite elastomer, which comprises raw materials of a deep eutectic solvent and an elastomer matrix, wherein the deep eutectic solvent is ethylene glycol (hydrogen bond donor)/lithium bistrifluoromethanesulfonylimide (hydrogen bond acceptor), and the molar ratio is 3: 1, the elastomer matrix is polydimethylsiloxane, and the deep eutectic solvent accounts for 30% of the total volume of the raw materials of the high dielectric constant composite elastomer.

The preparation method of the high dielectric constant composite elastomer comprises the following steps:

(1) fully mixing ethylene glycol and lithium bistrifluoromethanesulfonylimide, standing, and obtaining a completely clear and transparent deep eutectic solvent when the solid completely disappears;

(2) mixing the deep eutectic solvent obtained in the step (1) with an elastomer substrate, and fully stirring to obtain uniform opaque emulsion which is a precursor solution of the high-dielectric-constant composite elastomer;

(3) curing the precursor solution obtained in the step (2) by a thermal curing method, wherein the thermal curing condition is 60 ℃, and the curing time is 4 hours;

(4) and (4) obtaining the high dielectric constant composite elastomer after the reaction in the step (3) is finished.

Example 3

The embodiment provides a high dielectric constant composite elastomer, which comprises raw materials of a deep eutectic solvent and an elastomer matrix, wherein the deep eutectic solvent is urea (hydrogen bond donor)/choline chloride (hydrogen bond acceptor), and the molar ratio is 2: 1, the elastomer matrix is polydimethylsiloxane, and the deep eutectic solvent accounts for 30% of the total volume of the raw materials of the high dielectric constant composite elastomer.

The preparation method of the high dielectric constant composite elastomer comprises the following steps:

(1) fully mixing urea and choline chloride, standing until the solid completely disappears to obtain a completely clear and transparent deep eutectic solvent;

(2) mixing the deep eutectic solvent obtained in the step (1) with an elastomer substrate, and fully stirring to obtain uniform opaque emulsion which is a precursor solution of the high-dielectric-constant composite elastomer;

(3) curing the precursor solution obtained in the step (2) by a thermal curing method, wherein the thermal curing condition is 60 ℃, and the curing time is 4 hours;

(4) and (4) obtaining the high dielectric constant composite elastomer after the reaction in the step (3) is finished.

Example 4

The embodiment provides a high dielectric constant composite elastomer, which comprises raw materials of a deep eutectic solvent and an elastomer matrix, wherein the deep eutectic solvent is ethylene glycol (hydrogen bond donor)/choline chloride (hydrogen bond acceptor), and the molar ratio is 2: 1, the elastomer matrix is polydimethylsiloxane, and the deep eutectic solvent accounts for 30% of the total volume of the raw materials of the high dielectric constant composite elastomer.

The preparation method of the high dielectric constant composite elastomer comprises the following steps:

(1) fully mixing ethylene glycol and choline chloride, standing until the solid completely disappears to obtain a completely clear and transparent deep eutectic solvent;

(2) mixing the deep eutectic solvent obtained in the step (1) with an elastomer substrate, and fully stirring to obtain uniform opaque emulsion which is a precursor solution of the high-dielectric-constant composite elastomer;

(3) curing the precursor solution obtained in the step (2) by a thermal curing method, wherein the thermal curing condition is 60 ℃, and the curing time is 4 hours;

(4) and (4) obtaining the high dielectric constant composite elastomer after the reaction in the step (3) is finished.

The photographs of the high dielectric constant composite elastomers obtained in examples 1 to 4 are shown in FIG. 1. The dielectric constant spectra of the high dielectric constant composite elastomers obtained in examples 1 to 4 are shown in FIG. 2, in which Urea/LiTFSI is example 1, EG/LiTFSI is example 2, Urea/ChCl is example 3, and EG/ChCl is example 4.

As can be seen from FIGS. 1 and 2, the composite elastomers obtained in examples 1 to 4 of the present application have good mechanical properties and high dielectric constant.

Comparative example 1

Unlike example 1, the deep eutectic solvent accounts for 3% of the total volume of the raw materials of the high dielectric constant composite elastomer.

The spectrum of the dielectric constant of the obtained composite elastomer is shown in FIG. 3. As can be seen from fig. 3, the dielectric constant of the obtained composite elastomer was hardly improved (less than 5%).

Comparative example 2

Unlike example 1, the deep eutectic solvent accounts for 50% of the total volume of the raw materials of the high dielectric constant composite elastomer.

The deep eutectic solvent phase separates from the elastomer precursor solution and does not form a homogeneous emulsion.

Comparative example 3

In contrast to example 1, the molar ratio urea/lithium bistrifluoromethanesulfonylimide was 8: 1.

the deep eutectic solvent crystallizes at room temperature and cannot be uniformly dispersed in the elastomer precursor solution.

Comparative example 4

In contrast to example 1, the elastomer matrix was polyethylacrylate.

The deep eutectic solvent and the elastomer matrix are mutually soluble, and the composite elastomer cannot be prepared.

The method is simple and convenient to operate, high in practicability, low in preparation process cost and 100% in product conversion rate, and the prepared composite material has high dielectric constant, low dielectric loss and low elastic modulus, and is a dielectric composite elastomer very suitable for large-scale industrial production.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Moreover, those skilled in the art will appreciate that while some embodiments herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is only for enhancement of understanding of the general background of the application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.