Silk ionic gel and preparation method thereof

Abstract

The invention discloses silk ionic gel and a preparation method thereof, and belongs to the technical field of conductive materials.The preparation method of the silk ionic gel comprises the following steps that silk fabric and ionic liquid are heated respectively, then the heated silk fabric is soaked in the heated ionic liquid, the temperature is kept unchanged, and standing is conducted till the silk fabric swells; placing the ionic liquid and the silk fabric in a heated vacuum environment together for defoaming treatment, and then transferring to a normal-temperature environment for standing for gelation; the silk fabric subjected to standing treatment in the normal-temperature environment and the ionic liquid continue to be heated and then transferred to the normal-temperature environment to continue gelatinization, and the silk fabric is prepared. The silk ionic gel has the advantages of stable mechanical property, long application time and no need of frequent replacement.

Description

Technical Field

[0001] The invention belongs to the technical field of conductive materials, and in particular relates to a silk ion gel and a preparation method thereof. Background Art

[0002] With the rapid development of smart wearable products, there is an urgent need for stretchable, conductive and transparent flexible materials. As a new type of sensing material, ion gel has the characteristics of high transparency, stable electrochemical properties, high conductivity, wide chemical window, and stable mechanical strength, so it has great development potential in smart wearables. However, due to the large amount of ionic liquid contained in it, the mechanical properties of most ion gels are weak, so their application is limited to a certain extent. In addition, the current methods for improving mechanical properties, such as multi-component polymerization, construction of sacrificial bonds, addition of physical fillers, etc., have complex preparation processes or poor interface compatibility, which makes ion gels unable to be used for a long time and need to be replaced frequently, with low economic benefits. Summary of the invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a silk ion gel and a preparation method thereof. The silk ion gel has stable mechanical properties, a long application time and does not require frequent replacement.

[0004] To achieve the above purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0005] A silk ion gel comprises the following steps:

[0006] (1) heating the silk fabric and the ionic liquid respectively, then immersing the heated silk fabric in the heated ionic liquid, keeping the temperature constant, and standing until the silk fabric swells;

[0007] (2) placing the ionic liquid and the silk fabric together in a heated vacuum environment for degassing, and then transferring them to a room temperature environment and allowing them to stand for gelation;

[0008] (3) The silk fabric and the ionic liquid which have been left to stand at room temperature are further heated and then transferred to room temperature for further gelation to obtain the product.

[0009] Furthermore, the silk fabric can be in any form such as woven fabric, knitted fabric or non-woven fabric.

[0010] Further, the ionic liquid includes one of 1-ethyl-3-methylimidazolium bis(trifluoromethyl yellow sulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium tetrafluorochlorosalt.

[0011] Furthermore, the amount of ionic liquid is 0.1-0.2 g / cm 2.

[0012] Furthermore, in step (1), the heating temperature is 80-90° C. and the standing time is 5-7 h.

[0013] Furthermore, in step (2), the heating temperature is 80-90° C. and the degassing time is 20-24 h.

[0014] Furthermore, the treatment time in step (2) at room temperature is 10-30 minutes.

[0015] Furthermore, in step (3), the heating temperature is 80-90° C. and the heating time is 3-15 h.

[0016] Furthermore, the standing time in step (3) at room temperature is 0.5-1.5h.

[0017] A silk ion gel is prepared by adopting the method.

[0018] The beneficial effects produced by the present invention are:

[0019] 1. In the present invention, the viscosity of the ionic liquid is reduced by heating the ionic liquid, thereby promoting the penetration of the ionic liquid in the silk fabric and improving the swelling effect on the silk fabric; the swelling temperature is also a key factor affecting the swelling effect. If the swelling temperature is too low, the swelling will not be complete and the swelling time will be increased. If the swelling temperature is too high, the silk fabric will be denatured and deformed, affecting the structural stability of the ion gel. Therefore, selecting a suitable swelling temperature can not only improve the swelling effect of the silk fabric, but also ensure the structural stability of the silk fabric and improve the quality of the ion gel.

[0020] 2. The preparation process of the ion gel in the present invention is simple, easy to operate, mild in preparation conditions, and uses green and environmentally friendly materials.

[0021] 3. In the present invention, silk fabric is used as raw material, and ionic liquid is directly used to swell the silk fabric to promote the formation of ion gel by the silk fabric. The direct swelling method retains the hierarchical structure inside the silk, so that the mechanical properties of the prepared ion gel are better than those of the existing ion gel. The prepared ion gel has good electrical conductivity, good flexibility, and good transparency, and has great application prospects in the field of intelligent sensing.

[0022] 4. During the preparation process, the swollen silk fabric is degassed at high temperature and placed at room temperature for a certain period of time for gelation, and then the temperature is continued to be raised and finally cooled to room temperature for gelation, which can further improve the performance of the ion gel. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a polarizing microscope image of silk ion gel;

[0024] Figure 2 is the Fourier transform infrared spectrum of the silk ion gel in Example 1-3;

[0025] Figure 3 is a graph showing the relationship between the modulus and shear strain of the silk ion gel in Examples 1-3;

[0026] Figure 4 The stress-strain curves of the silk fabric ion gels prepared in Examples 1-3 and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments.

[0028] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0029] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0030] The features and performance of the present invention are further described in detail below in conjunction with the embodiments and drawings.

[0031] Example 1

[0032] A silk ion gel, the preparation method of which comprises the following steps:

[0033] (1) The silk plain fabric was cut into 1 cm*5 cm pieces, and then the silk fabric and the ionic liquid 1-butyl-3-methylimidazolium tetrafluorochloride were placed in an oven, heated to 90°C, and treated for 48 hours to remove excess moisture; then the heated silk fabric was immersed in the heated ionic liquid, the temperature was kept constant, and the silk fabric was allowed to stand for 6 hours until the silk fabric swelled. The amount of ionic liquid used was 0.2 g / cm 2 ;

[0034] (2) placing the ionic liquid and the silk fabric together in a vacuum environment at a heating temperature of 90°C for degassing for 24 hours, and then transferring the two to a room temperature environment and standing for 20 minutes for gelation;

[0035] (3) The silk fabric and ionic liquid after being left to stand at room temperature are further heated to 90°C for 3 hours, and then transferred to room temperature for further gelation for 1 hour to obtain the product.

[0036] Example 2

[0037] A silk ion gel, the preparation method of which comprises the following steps:

[0038] (1) The silk twill fabric was cut into 1 cm*5 cm pieces, and then the silk fabric and the ionic liquid 1-butyl-3-methylimidazolium tetrafluorochloride were placed in an oven, heated to 85°C, and treated for 48 hours to remove excess moisture; then the heated silk fabric was immersed in the heated ionic liquid, the temperature was kept constant, and the silk fabric was allowed to stand for 5 hours until the silk fabric swelled. The amount of ionic liquid used was 0.1 g / cm 2 ;

[0039] (2) placing the ionic liquid and the silk fabric together in a vacuum environment at a heating temperature of 85°C for degassing for 20 hours, and then transferring the two to a room temperature environment and standing for 10 minutes for gelation;

[0040] (3) The silk fabric and ionic liquid after being left to stand at room temperature are further heated to 85°C for 15 hours, and then transferred to room temperature for further gelation for 1.5 hours to obtain the product.

[0041] Example 3

[0042] A silk ion gel, the preparation method of which comprises the following steps:

[0043] (1) The silk plain fabric was cut into 1 cm*5 cm pieces, and then the silk fabric and the ionic liquid 1-butyl-3-methylimidazolium tetrafluorochloride were placed in an oven respectively, heated to 80°C, and treated for 48 hours to remove excess moisture; then the heated silk fabric was immersed in the heated ionic liquid, the temperature was kept constant, and the silk fabric was allowed to stand for 6 hours until the silk fabric swelled. The amount of ionic liquid used was 0.15 g / cm 2 ;

[0044] (2) placing the ionic liquid and the silk fabric together in a vacuum environment at a heating temperature of 80°C for degassing for 22 hours, and then transferring the two to a room temperature environment and standing for 20 minutes for gelation;

[0045] (3) The silk fabric and ionic liquid after being left to stand at room temperature are further heated to 80°C for 6 hours, and then transferred to room temperature for further gelation for 1 hour to obtain the product.

[0046] Example 4

[0047] A silk ion gel, the preparation method of which comprises the following steps:

[0048] (1) Cut the silk plain fabric into 1 cm*5 cm, then put the silk fabric and ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl yellow sulfonyl)imide into an oven, heat to 90°C, treat for 48 hours, and remove excess moisture; then immerse the heated silk fabric in the heated ionic liquid, keep the temperature constant, and let it stand for 6 hours until the silk fabric swells. The amount of ionic liquid used is 0.1 g / cm 2 ;

[0049] (2) placing the ionic liquid and the silk fabric together in a vacuum environment at a heating temperature of 85°C for degassing for 24 hours, and then transferring the two to a room temperature environment and standing for 25 minutes for gelation;

[0050] (3) The silk fabric and ionic liquid after being left to stand at room temperature are further heated to 85°C for 9 hours, and then transferred to room temperature for further gelation for 1 hour to obtain the product.

[0051] Example 5

[0052] A silk ion gel, the preparation method of which comprises the following steps:

[0053] (1) The silk plain fabric was cut into 1 cm*5 cm pieces, and then the silk fabric and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate were placed in an oven, heated to 80°C, and treated for 48 hours to remove excess moisture; then the heated silk fabric was immersed in the heated ionic liquid, the temperature was kept constant, and the silk fabric was allowed to stand for 7 hours until the silk fabric swelled. The amount of ionic liquid used was 0.2 g / cm 2 ;

[0054] (2) placing the ionic liquid and the silk fabric together in a vacuum environment at a heating temperature of 85°C for degassing for 20 hours, and then transferring the two to a room temperature environment and standing for 15 minutes for gelation;

[0055] (3) The silk fabric and ionic liquid after being left to stand at room temperature are further heated to 90°C for 6 hours, and then transferred to room temperature for further gelation for 0.5 hours to obtain the product.

[0056] Example 6

[0057] A silk ion gel, the preparation method of which comprises the following steps:

[0058] (1) The silk plain fabric was cut into 1 cm*5 cm pieces, and then the silk fabric and the ionic liquid 1-butyl-3-methylimidazolium tetrafluorochloride were placed in an oven, heated to 90°C, and treated for 48 hours to remove excess moisture; then the heated silk fabric was immersed in the heated ionic liquid, the temperature was kept constant, and the silk fabric was allowed to stand for 6 hours until the silk fabric swelled. The amount of ionic liquid used was 0.2 g / cm 2 ;

[0059] (2) placing the ionic liquid and the silk fabric together in a vacuum environment at a heating temperature of 90°C for degassing for 20 hours, and then transferring the two to a room temperature environment and standing for 10 minutes for gelation;

[0060] (3) The silk fabric and ionic liquid after being left to stand at room temperature are further heated to 80°C for 12 hours, and then transferred to room temperature for further gelation for 1.5 hours to obtain the product.

[0061] Comparative Example 1

[0062] A silk ion gel, the preparation method of which comprises the following steps:

[0063] (1) The silk plain fabric was cut into 1 cm*5 cm pieces, and then the silk fabric and the ionic liquid 1-butyl-3-methylimidazolium tetrafluorochloride were placed in an oven, heated to 90°C, and treated for 48 hours to remove excess moisture; then the heated silk fabric was immersed in the heated ionic liquid, the temperature was kept constant, and the silk fabric was allowed to stand for 6 hours until the silk fabric swelled. The amount of ionic liquid used was 0.2 g / cm 2 ;

[0064] (2) The ionic liquid and the silk fabric are placed together in a vacuum environment at a heating temperature of 90°C for degassing for 24 hours, and then the two are transferred to a room temperature environment and allowed to stand for 1 hour for gelation treatment to obtain a product.

[0065] Test example

[0066] Taking the ion gel in the embodiment as an example, the performance of the ion gel was tested. The specific results are shown in Figure 1-3 .

[0067] Figure 1 This is a polarizing microscope image of silk ion gel. The results show that the diameter of the silk sample increases after being treated with ionic liquid, indicating that the silk absorbs the ionic liquid and swells.

[0068] Figure 2 The Fourier transform infrared spectra of the silk ion gel in Examples 1-3 show that the spectra of the silk fabric and the silk ion gel are basically consistent, no new peaks are generated, and no peak disappearance occurs. The intensity and wave number of the corresponding peaks are also very close, which indicates that the silk fabric is only swollen by [BMIM]Cl without chemical reaction, and only physical changes occur in the whole process;

[0069] Figure 3 The figure is a relationship diagram between the modulus and shear strain of the silk ion gel in Examples 1-3; wherein, the storage modulus (G') and loss modulus (G") of the silk fabric ion gel represent the elastic and viscous components in the material, respectively. The results show that within the shear strain range of 0%-7%, the G' of the silk ion gel in different treatment groups is always greater than G", indicating the successful formation of the gel state.

[0070] Figure 4 The stress-strain curves of the silk fabric ion gels prepared in Examples 1-3 and Comparative Example 1 show that the strength of the silk ion gels in the examples is nearly 78% lower than that of the blank silk fabric, but the breaking strain is almost doubled, and the breaking strength of the treated silk ion gel is close to 10 MPa, which is much higher than the existing ion gel; while the breaking strain of the silk ion gel in Comparative Example 1 is significantly lower than that of the silk ion gel in Example 1.

Claims

1. A silk ion gel, characterized in that: The following steps are involved: (1) heating the silk fabric and the ionic liquid respectively, then immersing the heated silk fabric in the heated ionic liquid, keeping the temperature constant, and standing until the silk fabric swells; (2) placing the ionic liquid and the silk fabric together in a heated vacuum environment for degassing, and then transferring them to a room temperature environment and allowing them to stand for gelation; (3) The silk fabric and the ionic liquid which have been left to stand at room temperature are further heated and then transferred to room temperature for further gelation to obtain the product.

2. The silk ion gel according to claim 1, characterized in that The ionic liquid includes one of 1-ethyl-3-methylimidazolium bis(trifluoromethyl yellow sulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium tetrafluorochlorosalt.

3. The silk ion gel according to claim 1, characterized in that: The dosage of ionic liquid is 0.1-0.2g / cm 2 .

4. The silk ion gel according to claim 1, characterized in that: In step (1), the heating temperature is 80-90° C. and the standing time is 5-7 h.

5. The silk ion gel according to claim 1, characterized in that: In step (2), the heating temperature is 80-90° C. and the degassing time is 20-24 h.

6. The silk ion gel according to claim 1, characterized in that: The treatment time in step (2) at room temperature is 10-30 minutes.

7. The silk ion gel according to claim 1, characterized in that: In step (3), the heating temperature is 80-90° C. and the heating time is 3-15 h.

8. The silk ion gel according to claim 1, characterized in that: The standing time in step (3) at room temperature is 0.5-1.5h.

9. A silk ion gel, characterized in that: The method is prepared by any one of claims 1 to 8.

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