Preparation method of sodium alginate modified deep eutectic gel with wave absorption and strain sensing functions

Abstract

The invention belongs to the technical field of deep eutectic gel wave-absorbing materials, and particularly relates to a preparation method of sodium alginate modified deep eutectic gel with wave-absorbing and strain-sensing functions, which comprises the following steps: mixing sodium alginate with deionized water, mechanically stirring for the first time to form gel A, adding a certain amount of acrylamide, mechanically stirring for the second time to form gel B, and stirring for the second time to form gel B; adding a certain amount of deep eutectic solution, mechanically stirring for the third time, performing ultrasonic vibration, vacuumizing to form gel C, and finally performing ultraviolet curing treatment on the gel C to obtain sodium alginate modified deep eutectic gel; according to the preparation method, complex equipment is not needed, the preparation period is short, the sodium alginate modified deep eutectic gel is added into deep eutectic solutions with different contents, the real part and imaginary part of the dielectric constant of the material are accurately controlled, the characteristic impedance is close to the free space impedance, meanwhile, the ion conduction efficiency is guaranteed, and optimization of wave absorption and sensing is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of deep eutectic gel wave-absorbing materials, and particularly relates to a preparation method of a sodium alginate modified deep eutectic gel with wave-absorbing and strain sensing functions. BACKGROUND

[0002] With the rapid development of intelligent wear, flexible electronics, human-computer interaction and robot technology, flexible strain sensors, as the core devices for capturing human motion, physiological signals and interaction information between robots and the external environment, have increasingly diversified performance and functional requirements. Not only do they need to achieve the synergy of high sensitivity, mechanical flexibility and stability, but also need to maintain accurate detection capability in complex electromagnetic environments. In the field of robots, electronic skin, as the "interface" system for robots to perceive the external environment, relies heavily on flexible strain sensors. Robot electronic skin needs to perceive contact force, strain and other signals in real time and accurately to achieve safe and precise interaction with the human body and objects, which puts high demands on the performance of sensors. In particular, in practical applications, there are a large number of electromagnetic radiation in the environment around the human body and the industrial environment where robots work, such as electromagnetic waves generated by smartphones, medical devices, industrial instruments, internal motors and control systems of robots. These electromagnetic interferences can cause distortion of sensor signals and decrease in signal-to-noise ratio, which severely limits the reliability of sensors in precise medical diagnosis, motion monitoring and robot electronic skin scenarios. Therefore, it is of great strategic significance to develop flexible materials with high strain sensitivity and high-efficiency electromagnetic interference resistance.

[0003] Wave-absorbing materials mainly realize the absorption of electromagnetic waves through the mechanism of dielectric loss and magnetic loss. Dielectric loss includes interface polarization loss, dipole polarization loss and conductive loss, and magnetic loss includes natural resonance, exchange resonance and eddy current loss. Some composite wave-absorbing materials rely on high filling amount of magnetic particles to improve magnetic loss, which leads to an increase in material density and a decrease in flexibility, and the effective absorption bandwidth is narrow in the high-frequency band (Ku band 12.4-18.00 GHz), which cannot cover the main interference frequency band of 5G communication. At the same time, the impedance matching property of the material is difficult to control, and the real part (ε') and imaginary part (ε'') of the dielectric constant are unbalanced, which leads to an increase in electromagnetic wave reflectivity and a decrease in far-field radar scattering cross section, and the effect is limited. Therefore, a gel material that can accurately control the real part and imaginary part of the dielectric constant and realize wave-absorbing and sensing is needed. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application proposes a preparation method of sodium alginate modified deep eutectic gel, which discards the high-temperature and multi-step crosslinking process, adopts room temperature dissolution and single-step crosslinking method, does not require complex equipment, has a short preparation period, and realizes the optimization of wave absorption and sensing by adding sodium alginate modified deep eutectic gel in different contents of deep eutectic solution, precisely controlling the real part and imaginary part of the material dielectric constant, making the characteristic impedance close to the free space impedance (377 Ω), and guaranteeing the ion conduction efficiency.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The present application provides a preparation method of sodium alginate modified deep eutectic gel with wave absorption and strain sensing, comprising the following steps: Step S1, mix sodium alginate and deionized water, first mechanical stirring to form gel A, then add a certain amount of acrylamide, second mechanical stirring to form gel B; Step S2, add a certain amount of deep eutectic solution to the gel B, third mechanical stirring, ultrasonic vibration, and vacuum extraction to form gel C; the addition amount of the deep eutectic solution is 360%~1800% of the mass of the sodium alginate; Step S3, ultraviolet curing treatment is performed on the gel C to obtain the sodium alginate modified deep eutectic gel.

[0006] Preferably, in step S1, the mass ratio of the sodium alginate to the deionized water is (1~10) : 100; and the addition amount of the acrylamide is 100%~1000% of the mass of the sodium alginate.

[0007] Preferably, in step S1, the first mechanical stirring time is 5~60 min, and the second mechanical stirring time is 2~90 min.

[0008] Preferably, in step S2, the third mechanical stirring time is 5~60 min, the ultrasonic vibration time is 5~60 min, the ultrasonic frequency is 40±2 KHz, and the vacuum degree after vacuum extraction is 0.085 MPa.

[0009] Preferably, in step S2, the deep eutectic solution is composed of choline chloride and mixed alcohol, the mass ratio of the choline chloride to the mixed alcohol is (1:0.96), and the mixed alcohol includes ethylene glycol, ethanol and glycerol.

[0010] Preferably, the mass ratio of the ethylene glycol, ethanol and glycerol is 1:1:1, 2:1:1, 1:2:1 or 1:1:2.

[0011] Preferably, in step S3, the light irradiation time of the ultraviolet curing treatment is 1~8 h.

[0012] Compared with the prior art, the present application has the following beneficial technical effects: The preparation method of the sodium alginate modified deep eutectic gel has low cost, simple process, is easy to industrialize, has short preparation time period, high repeatability and controllability, and has the potential for industrialization.

[0013] The prepared sodium alginate modified deep eutectic gel has the characteristics of thinness, softness and strong compatibility, has wide-band electromagnetic wave absorption capacity and high sensitivity flexible sensing capacity.

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described below. It should be noted that the drawings described below only relate to some embodiments of the present disclosure, rather than limiting the present disclosure, wherein: Figure 1 is a real object diagram of the sodium alginate modified deep eutectic gel prepared by the present application embodiment 1, comparative example 1 and comparative example 2.

[0015] Figure 2 is a mechanical property test result diagram of the sodium alginate modified deep eutectic gel of the present application embodiment 1, comparative example 1 and comparative example 2.

[0016] Figure 3 is a wave absorption performance test result diagram of the sodium alginate modified deep eutectic gel in the present application embodiment 1.

[0017] Figure 4 is a wave absorption performance test result diagram of the sodium alginate modified deep eutectic gel in the present application comparative example 1.

[0018] Figure 5 is a wave absorption performance test result diagram of the sodium alginate modified deep eutectic gel in the present application comparative example 2.

[0019] Figure 6 is a sensing performance test result diagram of the sodium alginate modified deep eutectic gel of the present application embodiment 1, comparative example 1 and comparative example 2. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor also belong to the scope of protection of the present disclosure.

[0021] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0022] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be incorporated in to other embodiments.

[0023] The application provides a preparation method of a sodium alginate modified deep eutectic gel with wave absorption and strain sensing, comprising the following steps: Step S1, mixing sodium alginate and deionized water, first mechanical stirring to form gel A, then adding a certain amount of acrylamide, second mechanical stirring to form gel B; Specifically, in step S1, the mass ratio of sodium alginate to deionized water is preferably (1-10):100, for example, it can be 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 1:10; the first mechanical stirring time is preferably 5-60 min, for example, it can be 5 min, 10 min, 15 min, 25 min, 35 min, 45 min, 55 min, 60 min, to form gel A, then add acrylamide, the addition amount of acrylamide is preferably 100%-1000% of the mass of sodium alginate, for example, it can be 100%, 200%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, 1000%, the second mechanical stirring time is preferably 2-90 min, for example, it can be 2 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min.

[0024] Step S2, adding a certain amount of deep eutectic solution to gel B, third mechanical stirring, ultrasonic vibration, and vacuum extraction to form gel C; the addition amount of deep eutectic solution is preferably 360%-1800% of the mass of sodium alginate, for example, it can be 360%, 500%, 800%, 1000%, 1200%, 1500%, 1800%; Specifically, in step S2, the deep eutectic solution is composed of choline chloride and mixed alcohol, and the mass ratio of choline chloride to mixed alcohol is (1:0.96), and the mixed alcohol includes ethylene glycol, ethanol and glycerol, and the mass ratio of ethylene glycol, ethanol and glycerol is 1:1:1, 2:1:1, 1:2:1 or 1:1:2.

[0025] Specifically, in step S2, the third mechanical stirring time is preferably 5-60 min, for example, it can be 5 min, 10 min, 15 min, 25 min, 35 min, 45 min, 55 min or 60 min, the ultrasonic vibration time is preferably 5-60 min, for example, it can be 5 min, 10 min, 15 min, 25 min, 35 min, 45 min, 55 min or 60 min, the ultrasonic frequency is 40±2 KHz, and the vacuum degree after vacuumizing is 0.085 MPa.

[0026] In step S3, the gel C is subjected to ultraviolet light curing treatment to obtain the sodium alginate modified deep eutectic gel.

[0027] Specifically, in step S3, the light irradiation time of the ultraviolet light curing treatment is preferably 1-8 h, for example, it can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h or 8 h.

[0028] The technical solutions in the present application will be described clearly and completely in combination with the embodiments in the present application as follows: Embodiment 1 This embodiment prepares a sodium alginate modified deep eutectic gel with wave absorption and strain sensing, which specifically includes the following steps: 0.5 g of sodium alginate is mixed with 10 ml of deionized water, and the first mechanical stirring is performed for 60 min to form a gel A; 4 g of acrylamide (the mass ratio of sodium alginate to acrylamide is 1:8) is added to the gel A, and the second mechanical stirring is performed for 60 min to obtain a gel B; 9 g of a deep eutectic solution (the deep eutectic solution is composed of 6 g of choline chloride, 2.07 g of ethylene glycol, 1.03 g of ethanol and 3.11 g of glycerol, and the mixture is stirred at 80℃ for 20 min) is added to the obtained gel B, and the third mechanical stirring is performed for 30 min, followed by 30 min of ultrasonic treatment, and then vacuumizing is performed to eliminate internal air bubbles; a gel C is obtained; The gel C is irradiated under ultraviolet light for 6 h to obtain a sodium alginate modified deep eutectic gel, as shown in S3 of Figure 1 .

[0029] Comparative Example 1 This comparative example prepares a sodium alginate modified deep eutectic gel with wave absorption and strain sensing, which specifically includes the following steps: Mix 0.5 g sodium alginate with 10 ml deionized water, first mechanical stirring for 60 min, forming gel A; 4 g acrylamide (sodium alginate and acrylamide mass ratio is 1:8) is added to the above gel A, second mechanical stirring for 60 min, to obtain gel B; 9 g deep eutectic solution (deep eutectic solution is prepared by stirring 6 g choline chloride, 6.22 g ethylene glycol at 80℃ for 20 min) is added to the obtained gel B, third mechanical stirring for 30 min, then 30 min ultrasonic treatment, and vacuum extraction to eliminate internal bubbles; to obtain gel C; The gel C is irradiated under ultraviolet light for 6 h to obtain a sodium alginate modified deep eutectic gel, as shown in S1 of Figure 1

[0030] Comparative Example 2 This example prepares a sodium alginate modified deep eutectic gel with wave absorption and strain sensing, specifically including: Mix 0.5 g sodium alginate with 10 ml deionized water, first mechanical stirring for 60 min, forming gel A; 4 g acrylamide (sodium alginate and acrylamide mass ratio is 1:8) is added to the above gel A, second mechanical stirring for 60 min, to obtain gel B; 9 g deep eutectic solution (deep eutectic solution is prepared by stirring 6 g choline chloride, 2.488 g ethylene glycol, 3.732 g ethanol at 80℃ for 20 min) is added to the obtained gel B, third mechanical stirring for 30 min, then 30 min ultrasonic treatment, and vacuum extraction to eliminate internal bubbles; to obtain gel C; The gel C is irradiated under ultraviolet light for 6 h to obtain a sodium alginate modified deep eutectic gel, as shown in S2 of Figure 1

[0031] Comparative Example 3 Mix 0.5 g sodium alginate with 10 ml deionized water, first mechanical stirring for 60 min, forming gel A; 4 g acrylamide (sodium alginate and acrylamide mass ratio is 1:8) is added to the above gel A, second mechanical stirring for 60 min, to obtain gel B; 12 g deep eutectic solution (deep eutectic solution is prepared by stirring 6 g choline chloride, 2.07 g ethylene glycol, 1.03 g ethanol and 3.11 g glycerol at 80℃ for 20 min) is added to the obtained gel B, third mechanical stirring for 30 min, then 30 min ultrasonic treatment, and vacuum extraction to eliminate internal bubbles; to obtain gel C; The gel C is irradiated under ultraviolet light for 6 h to obtain a sodium alginate modified deep eutectic gel.

[0032] ​​Compared with Example 1, the eutectic solution added in the comparative example exceeds the set range, so that the hydrogen bond content of the obtained eutectic gel is too high, the toughness of the eutectic gel is poor, and the support is insufficient.

[0033] Comparative Example 4 0.5 g of sodium alginate was mixed with 10 ml of deionized water, and mechanically stirred for 60 min for the first time to form gel A; 4 g of acrylamide (the mass ratio of sodium alginate to acrylamide was 1:8) was added to the above gel A, and mechanically stirred for 60 min for the second time to obtain gel B; 1.5 g of eutectic solution (the eutectic solution was prepared by stirring 6 g of choline chloride, 2.07 g of ethylene glycol, 1.03 g of ethanol and 3.11 g of glycerol at 80°C for 20 min) was added to the obtained gel B, and mechanically stirred for 30 min for the third time, and then ultrasonic treated for 30 min, and then vacuumized to eliminate internal bubbles; gel C was obtained; The gel C was irradiated under ultraviolet light for 6 h to obtain a sodium alginate modified eutectic gel.

[0034] Compared with Example 1, the eutectic solution added in the comparative example exceeds the set range, so that the hydrogen bond content of the obtained eutectic gel is too low, the flexibility of the eutectic gel is insufficient, and the stretchability is poor.

[0035] Figure 1 In the table, S3 is the sodium alginate modified eutectic gel prepared in Example 1, S1 and S2 are the sodium alginate modified eutectic gels prepared in Comparative Examples 1 and 2, which shows that S1, S2 and S3 all have good optical transparency; Figure 2 The mechanical property detection results of the sodium alginate modified eutectic gels of Example 1 and Comparative Examples 1-2 show that the mechanical property curve S3 of Example 1 is higher than the curves S1 of Comparative Example 1 and S2 of Comparative Example 2, which shows that the tensile strength of Example 1 is optimal; Figures 3-5 The wave absorption performance detection results of the sodium alginate modified eutectic gel materials, the wave absorption performance of the prepared sodium alginate modified eutectic gel materials was tested by a vector network analyzer (VNA, Anritsu MS46322B, Japan), Figure 3 The wave absorption performance results of Example 1 show that in the test range of 12.4-18.00 GHz, the effective bandwidth of RL<-10 dB (90% electromagnetic wave loss) is 5.6 GHz (12.4-18.00 GHz) at a thickness of 1.70 mm, which shows that the absorption bandwidth can completely cover the electromagnetic waves of the ku band and has excellent wave absorption performance.

[0036] Figure 6For the detection results of the sensing performance of the sodium alginate modified deep eutectic gel of example 1 and comparative examples 1-2, the resistivity change of the sodium alginate modified deep eutectic gel under different bending angles is measured, and it can be obviously seen that example 1 has the most sensitive resistance change, indicating that it has the optimal sensing performance.

[0037] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a sodium alginate modified deep eutectic gel with wave absorption and strain sensing, characterized in that, The method comprises the following steps: S1, mixing sodium alginate and deionized water to form gel A by first mechanical stirring, then adding a certain amount of acrylamide to form gel B by second mechanical stirring; S2, adding a certain amount of deep eutectic solution to the gel B, then performing third mechanical stirring, ultrasonic vibration and vacuum extraction to form gel C; the amount of the deep eutectic solution added is 360% to 1800% of the mass of the sodium alginate; S3, performing ultraviolet light curing treatment on the gel C to obtain the sodium alginate modified deep eutectic gel.

2. The preparation method of the sodium alginate modified deep eutectic gel with wave absorption and strain sensing according to claim 1, characterized in that, The mass ratio of the sodium alginate to the deionized water in S1 is (1-10):100; the amount of the acrylamide added is 100% to 1000% of the mass of the sodium alginate.

3. The preparation method of the sodium alginate modified deep eutectic gel with wave absorption and strain sensing according to claim 1, characterized in that, In S1, the first mechanical stirring is performed for 5-60 min, and the second mechanical stirring is performed for 2-90 min.

4. The preparation method of the sodium alginate modified deep eutectic gel with wave absorption and strain sensing according to claim 1, characterized in that, In S2, the third mechanical stirring is performed for 5-60 min, the ultrasonic vibration is performed for 5-60 min, the ultrasonic frequency is 40±2 KHz, and the vacuum degree after the vacuum extraction is 0.085 MPa.

5. The preparation method of the sodium alginate modified deep eutectic gel with wave absorption and strain sensing according to claim 1, characterized in that, In S2, the deep eutectic solution is composed of choline chloride and mixed alcohol, the mass ratio of the choline chloride to the mixed alcohol is (1:0.96), and the mixed alcohol comprises ethylene glycol, ethanol and glycerol.

6. The preparation method of a sodium alginate modified deep eutectic gel with wave absorption and strain sensing according to claim 5, characterized in that, The mass ratio of the ethylene glycol, ethanol and glycerol is 1:1:1, 2:1:1, 1:2:1 or 1:1:

2.

7. The preparation method of a sodium alginate modified deep eutectic gel with wave absorption and strain sensing according to claim 1, characterized in that, In S3, the light irradiation time of the ultraviolet light curing treatment is 1-8 h.

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