Gradient poly-eutectic solvent elastomer composition for flexible sensor as well as preparation and application of gradient poly-eutectic solvent elastomer composition

Abstract

The invention discloses a gradient poly-eutectic solvent elastomer composition for a flexible sensor as well as preparation and application of the gradient poly-eutectic solvent elastomer composition. The gradient poly eutectic solvent elastomer can be used for a flexible sensor, and contains a polymerizable eutectic solvent capable of endowing the elastomer with a conductive characteristic, a polymerizable hyperbranched organic silicon cross-linking agent and a photoinitiator. The gradient poly-eutectic solvent elastomer for the flexible sensor has the beneficial effects that the prepared gradient poly-eutectic solvent elastomer for the flexible sensor has good tensile property and fatigue resistance; the prepared gradient poly-eutectic solvent elastomer for the flexible sensor has multiple sensing properties; and the prepared gradient poly-eutectic solvent elastomer for the flexible sensor has good biocompatibility.

Description

Technical Field

[0001] This invention belongs to the field of functional polymer conductive materials technology, specifically relating to a gradient polyeutectic solvent elastomer composition for flexible sensors and its preparation and application. Background Art

[0002] Flexible sensors can convert external stimuli (such as strain or pressure) into detectable electrical signals, showing great application potential in fields such as medical diagnostics, intelligent robotics, and human-computer interaction. Flexible conductive materials are the core components of flexible sensors, making their structural design and fabrication methods particularly important. Due to their unique flexibility and stability, ionogels, as an emerging soft conductor material, have already begun to show promise in the field of flexible electronic devices.

[0003] Gradient ionogels have been used to fabricate flexible sensors with high sensitivity and wide detection range. However, gradient ionogels face challenges such as the high toxicity of ionic liquids and the leakage of conductive liquids, which limits the safety and applicability of gradient ionogel-based flexible sensors in human-related applications. Therefore, developing a gradient conductive material with no risk of conductive liquid leakage and low toxicity has become an urgent problem to be solved in the field of flexible sensors. Summary of the Invention

[0004] Based on the above background, this invention provides a gradient polyeutectic solvent elastomer composition for flexible sensors, its preparation, and its application. This composition exhibits gradient conductivity, excellent fatigue resistance, superior tensile properties, low cytotoxicity, and the ability to convert various stimuli into electrical signals. Through extensive and in-depth research, this invention prepares a series of gradient polyeutectic solvent elastomer compositions by compounding a self-floating, free-radical polymerizable hyperbranched organosilicon crosslinking agent, a polymerizable eutectic solvent, and a photoinitiator.

[0005] Specifically, the present invention includes:

[0006] A gradient polyeutectic solvent elastomer composition for flexible sensors, the composition comprising a polymerizable hyperbranched silicone crosslinking agent, a polymerizable eutectic solvent, and a photoinitiator;

[0007] The polymerizable hyperbranched organosilicon crosslinking agent has the structural formula shown in formula a:

[0008]

[0009] R is independently selected from:

[0010] Preferably, the polymerizable eutectic solvent is prepared from olefinic carboxylic acids and choline chloride in different molar ratios; the olefinic carboxylic acids are selected from acrylic acid and methacrylic acid, preferably acrylic acid; the molar ratio of the olefinic carboxylic acid to choline chloride is 1:1 to 4:1.

[0011] Preferably, the photoinitiator is selected from one or more free radical photoinitiators.

[0012] Preferably, the molar ratio of the polymerizable hyperbranched organosilicon crosslinking agent to the polymerizable eutectic solvent is (1-50):1000; the molar ratio of the photoinitiator to the polymerizable eutectic solvent is (1-50):1000.

[0013] This invention provides a method for preparing the gradient polyeutectic solvent elastomer for flexible sensors described above, comprising the following steps:

[0014] A polymerizable eutectic solvent is mixed with a polymerizable hyperbranched organosilicon crosslinking agent and a photoinitiator to obtain a precursor solution. Precursor solutions with different formulations are allowed to stand for 0.5 to 2 hours, and photopolymerization is initiated under oxygen-barrier conditions and LED light irradiation to obtain a cured gradient polyeutectic solvent elastomer.

[0015] Preferably, the LED light wavelengths are 365nm, 385nm, 395nm, and 405nm, and the light intensity is 100mW / cm² for each. 2 The irradiation time is 5-60 minutes.

[0016] In another aspect, the present invention provides the application of the gradient polyeutectic solvent elastomer for flexible sensors described above in flexible sensors.

[0017] The beneficial effects of the present invention are:

[0018] 1. The gradient polyeutectic solvent elastomer prepared by the present invention exhibits gradient conductivity and good fatigue resistance due to the introduction of a polymerizable hyperbranched organosilicon crosslinking agent;

[0019] 2. The gradient polyeutectic solvent elastomer composition prepared by the present invention has good biocompatibility, and this gradient polyeutectic solvent elastomer has broad application prospects in the field of flexible electronic sensors for human-related applications. Attached Figure Description

[0020] Figure 1 , 2 The stress-strain curves of the gradient polyeutectic solvent elastomer composition prepared in Example 6 are shown.

[0021] Figure 3 , 4The compressive stress-compressive strain curves are those of the gradient polyeutectic solvent elastomer composition prepared in Example 6.

[0022] Figure 5 The gradient polyeutectic solvate elastomer composition A-Si prepared in Example 7 0.15 Stress-strain curves during continuous tensile cycles;

[0023] Figure 6 The gradient polyeutectic solvate elastomer composition A-Si prepared in Example 7 0.15 Stress-strain curves during continuous compression cycles;

[0024] Figure 7 The gradient polyeutectic solvate elastomer composition A-Si prepared in Example 7 0.15 The ΔR / R0 strain curve;

[0025] Figure 8 The gradient polyeutectic solvate elastomer composition A-Si prepared in Example 7 0.15 The ΔR / R0 pressure curve;

[0026] Figure 9 The gradient polyeutectic solvate elastomer composition A-Si prepared in Example 7 0.15 The ΔR / R0-time curve for temperature increase from 26℃ to 60℃;

[0027] Figure 10 The gradient polyeutectic solvate elastomer composition A-Si prepared in Example 7 0.15 Comparison of biocompatibility with the gradient conductive ion gel prepared in Example 9. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] [Example 1]

[0030] Preparation of polymerizable hyperbranched organosilicon crosslinking agent (HPSi)

[0031] At 25°C, γ-methacryloyloxypropyltrimethoxysilane (24.8 g, 10 mmol) and deionized water (2.3 g, 130 mmol) were added to a 100 mL round-bottom flask. Dilute hydrochloric acid (1 mol / L) was added dropwise with stirring to adjust the pH of the reaction solution to 1–2. The reaction solution was then heated to 50°C and maintained for 5 h. Afterward, methanol was removed by rotary evaporation under reduced pressure to obtain a colorless, transparent, polymerizable hyperbranched organosilicon crosslinking agent, HPSi, whose M... w The concentration was 1606 g / mol, and the degree of branching was 0.41.

[0032]

Examples 2-4

[0033] Preparation of polymerizable eutectic solvents A, B, and C

[0034] Acrylic acid (AA) and choline chloride (ChCl) (13.96 g, 0.1 mol) were added to 100 mL round-bottom flasks at molar ratios of 20:10, 22:10 and 24:10, respectively. The mixtures were stirred at 60 °C for 15 min to obtain colorless and transparent liquids, which were polymerizable eutectic solvents A, B and C, respectively.

[0035]

Example 5

[0036] This embodiment illustrates that a gradient polyeutectic solvent elastomer composition prepared from polymerizable eutectic solvents A, B, and C has gradient conductivity.

[0037] A gradient poly(eutectic solvent elastomer) composition was prepared according to the formulations in Table 1, using photoinitiator ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO-L), a polymerizable hyperbranched organosilicon crosslinking agent (HPSi), and polymerizable eutectic solvents A, B, or C. After thorough mixing, the gradient poly(eutectic solvent elastomer) composition was poured into a polytetrafluoroethylene mold (10×10×10mm) and allowed to stand for 1 hour. The mixture was then subjected to oxygen-barrier conditions and a light intensity of 100 mW / cm². 2 The graded polyeutectic solvent elastomers were obtained by irradiating them with an LED lamp with a wavelength of 365 nm for 5 minutes. The conductivity σ of the graded polyeutectic solvent elastomers was then tested by AC impedance spectroscopy, and the results are shown in Table 1. The conductivity (σ) of the graded polyeutectic solvent elastomer compositions prepared from polymerizable eutectic solvents A, B, and C increases from the upper to the lower layers, indicating that the graded polyeutectic solvent elastomer compositions prepared from polymerizable eutectic solvents A, B, and C exhibit graded conductivity.

[0038] Table 1 Formulations of gradient polyeutectic solvent elastomer compositions

[0039] formula <![CDATA[A-Si 0.15 ]]> <![CDATA[B-Si 0.15 ]]> <![CDATA[C-Si 0.15 ]]> A (mmol) 10 0 0 B (mmol) 0 10 0 A (mmol) 0 0 10 n(TPO-L):n(A) 3:1000 0:1000 0:1000 n(TPO-L):n(B) 0:1000 3:1000 0:1000 n(TPO-L):n(C) 0:1000 0:1000 3:1000 n(HPSi):n(A) 15:1000 0:1000 0:1000 n(HPSi):n(B) 0:1000 15:1000 0:1000 n(HPSi):n(C) 0:1000 0:1000 15:1000 <![CDATA[σ 上层 (mS cm -1 )]]> 0.095 0.024 0.009 <![CDATA[σ 下层 (mS cm -1 )]]> 0.132 0.076 0.047

[0040]

Example 6

[0041] The purpose of this embodiment is to illustrate that gradient polyeutectic solvent elastomer compositions have good stretchability and compressibility.

[0042] The formulations of the gradient polymer low-melt solvent elastomer compositions are shown in Table 2. The cured gradient polymer low-melt solvent elastomer compositions were subjected to uniaxial tensile and compression tests at 25°C using a universal testing machine. The test results are shown in [Table 2]. Figure 1-4 .Depend on Figure 1 and 2 It can be seen that the prepared gradient polyeutectic solvent elastomer has good deformation capacity, with a fracture strain higher than 2500%. With the increase of the molar ratio of AA and ChCl, the fracture stress of the elastomer is significantly improved, and the fracture strain exceeds 2500%. Increasing the HPSi content reduces the fracture strain of the elastomer from 2880% to 1869%, while the fracture stress shows a trend of first increasing and then decreasing, reaching a maximum of 2.71 MPa. Figure 3 and 4 It can be seen that the compressive stress of the elastomer increases significantly with increasing AA content. Among them, C-Si has the highest AA content. 0.15 The compressive stress reached 15.80 MPa. With the increase of crosslinking agent HPSi content, the compressive stress of the elastomer showed a trend of first rising and then falling. This trend was consistent with the change in the tensile properties of the elastomer.

[0043] Table 2 Formulations of Gradient Polymer Oeutectic Solvent Elastomer Compositions

[0044] formula <![CDATA[A-Si 0.15 ]]> <![CDATA[B-Si 0.15 ]]> <![CDATA[C-Si 0.15 ]]> <![CDATA[A-Si 0.25 ]]> <![CDATA[A-Si 0.35 ]]> A (mmol) 10 0 0 10 10 B (mmol) 0 0 0 0 0 C(mmol) 0 0 10 0 0 n(TPO-L):n(A) 3:1000 0:1000 0:1000 3:1000 3:1000 n(TPO-L):n(B) 0:1000 3:1000 0:1000 0:1000 0:1000 n(TPO-L):n(C) 0:1000 0:1000 3:1000 0:1000 0:1000 n(HPSi):n(A) 15:1000 0:1000 0:1000 25:1000 35:1000 n(HPSi):n(B) 0:1000 15:1000 0:1000 0:1000 0:1000 n(HPSi):n(C) 0:1000 0:1000 15:1000 0:1000 0:1000

[0045]

Example 7

[0046] The purpose of this embodiment is to illustrate that gradient polyeutectic solvent elastomer compositions have excellent fatigue resistance.

[0047] The formulations of the gradient poly(oligomel) solvent elastomer compositions are shown in Table 3. The cured gradient poly(oligomel) solvent elastomer compositions were subjected to continuous cyclic tensile and cyclic compression tests at 25°C using a universal testing machine, with 20 cycles in each test. The test results are shown in [Table 3]. Figure 5 and Figure 6 After the 15th tensile cycle, the maximum tensile stress of the elastomer remained at approximately 510 kPa, about 88.5% of that in the first cycle. After 18 compression cycles, the maximum compressive stress of the elastomer was 84.2% of that in the first cycle. This indicates that the gradient polyeutectic solvent elastomer composition exhibits excellent fatigue resistance.

[0048] Table 3 Formulations of gradient polyeutectic solvent elastomer compositions

[0049] formula A (mmol) n(TPO-L):n(A) n(HPSi):n(AA) <![CDATA[A-Si 0.15 ]]> 10 3:1000 15:1000

[0050]

Example 8

[0051] This embodiment illustrates that the gradient polyeutectic solvent elastomer composition has multiple sensing properties.

[0052] The formulations of the gradient poly(oligomel) solvent elastomer compositions are shown in Table 3. The strain, pressure, and temperature sensing properties of the cured gradient poly(oligomel) solvent elastomer compositions were tested using a universal testing machine coupled with a source meter. The results are as follows: Figure 7 As shown. From Figure 7 It can be seen that as the applied strain increases, the ΔR / R0 of the gradient poly(eutectic solvent elastomer) composition gradually increases. A linear fit was performed on the ΔR / R0-strain curve of the gradient poly(eutectic solvent elastomer) composition, and the R0 of the fitted curve was found to be within the entire strain working range (0–500%). 2 All values ​​were above 0.995, indicating a high linear correlation between ΔR / R0 and strain in the gradient polyeutectic solvent elastomer composition, demonstrating strain sensing properties. Figure 8 It can be seen that in the low-pressure region (0–50 kPa), the resistivity of the gradient polyeutectic solvent elastomer composition decreases rapidly with increasing pressure, exhibiting high sensitivity. In particular, for the 0–2 kPa range, the sensitivity of the gradient polyeutectic solvent elastomer composition reaches 0.16 kPa. -1 For the medium pressure range (50–300 kPa), the sensitivity of the gradient polyeutectic solvent elastomer composition is 9.01 × 10⁻⁶. -4 kPa -1 For high-pressure regions (300–1000 kPa), the sensitivity of gradient polyeutectic solvent elastomer compositions is 1.50 × 10⁻⁶. -4 kPa -1 This indicates that the gradient polyeutectic solvent elastomer composition possesses pressure-sensing properties. From Figure 9 It can be seen that the resistance of the gradient polyeutectic solvent elastomer composition is negatively correlated with temperature. As the ambient temperature increases from 26℃ to 60℃, the ΔR / R0 of the gradient polyeutectic solvent elastomer composition gradually decreases, indicating that the gradient polyeutectic solvent elastomer composition has temperature sensing properties. In summary, this shows that the gradient polyeutectic solvent elastomer composition has multiple sensing properties.

[0053]

Example 9

[0054] This embodiment illustrates that the gradient polyeutectic solvent elastomer composition has good biocompatibility.

[0055] The formulations of the gradient-polymer eutectic solvent elastomer compositions are shown in Table 3. The graded-polymer eutectic solvent elastomer A-Si prepared from a low-toxicity, highly biocompatible eutectic solvent was investigated. 0.15 The biocompatibility, and its compatibility with the gradient conductive ion gel MSi prepared by ion liquid. 0.15 A comparison was made.

[0056] The formulation of the gradient conductive ionogel composition is shown in Table 4, and the preparation method is as follows:

[0057] A gradient conductive ion gel composition was prepared according to the formulations in Table 4 using ionic liquids 1-ethyl-3-methylimidazolium sulfate (EMIMES), HPSi, AA, and TPO-L. After thorough stirring, the gradient conductive ion gel composition was poured into a polytetrafluoroethylene mold (10×10×10mm) and allowed to stand for 1 hour. The mixture was then subjected to oxygen-barrier conditions and a light intensity of 100 mW / cm². 2 Irradiate the light for 5 minutes under an LED light with an emission wavelength of 365nm.

[0058] Given that the prepared flexible conductive material is mainly used in wearable flexible sensors, human embryonic kidney cells HEK-293T were selected, and cytotoxicity tests were performed according to the national standard GB / T 16886. The results are as follows: Figure 10 As shown. After 24 hours of incubation, the 1 vol% concentration extracts of both conductive materials maintained cell viability above 98%. With increasing extract concentration, cell viability began to decline. However, A-Si... 0.15 Cell viability cultured from elastomer extracts was consistently higher than that of MSi. 0.15 Ion gel, indicating A-Si 0.15 Its cytotoxicity is lower than that of MSi. 0.15 Ionogels have better biocompatibility.

[0059] Table 4 Formulation of Gradient Conductive Ion Gel Composition

[0060]

[0061] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A gradient polyeutectic solvent elastomer composition for flexible sensors, the gradient polyeutectic solvent elastomer composition comprising a polymerizable hyperbranched organosilicon crosslinking agent, a polymerizable eutectic solvent, and a photoinitiator.

2. The gradient polyeutectic solvent elastomer composition for flexible sensors according to claim 1, characterized in that, The polymerizable hyperbranched organosilicon crosslinking agent has the structural formula shown in formula a: R is independently selected from:

3. The gradient polyeutectic solvent elastomer composition for flexible sensors according to claim 1, characterized in that, The polymerizable eutectic solvent is prepared from olefinic carboxylic acids and choline chloride in different molar ratios; the olefinic carboxylic acids are selected from acrylic acid and methacrylic acid, preferably acrylic acid; the molar ratio of the olefinic carboxylic acid to choline chloride is 1:1 to 4:

1.

4. The gradient polyeutectic solvent elastomer composition for flexible sensors according to claim 1, characterized in that, The photoinitiator is selected from one or more free radical photoinitiators.

5. The gradient polyeutectic solvent elastomer composition for flexible sensors according to claim 1, characterized in that, The molar ratio of the polymerizable hyperbranched organosilicon crosslinking agent to the polymerizable eutectic solvent is (1-50):1000; the molar ratio of the photoinitiator to the polymerizable eutectic solvent is (1-50):1000.

6. The method for preparing the gradient polyeutectic solvent elastomer composition for flexible sensors according to any one of claims 1-5, characterized in that, Includes the following steps: A polymerizable eutectic solvent is mixed with a polymerizable hyperbranched organosilicon crosslinking agent and a photoinitiator to obtain a precursor solution. Precursor solutions with different formulations are allowed to stand for 0.5 to 2 hours, and polymerization is initiated under oxygen-barrier conditions and LED light irradiation to obtain a cured gradient polyeutectic solvent elastomer.

7. The method for preparing the gradient polyeutectic solvent elastomer composition for flexible sensors according to claim 6, characterized in that, The LEDs have wavelengths of 365nm, 385nm, 395nm, and 405nm, and a light intensity of 100mW / cm² for each. 2 The irradiation time is 5 to 60 minutes.

8. The gradient polyeutectic solvent elastomer composition for flexible sensors according to any one of claims 1-5 is applied to flexible sensors.

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