Preparation method of 3, 4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel

Abstract

The invention discloses a preparation method of 3, 4-dihydroxy benzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, and belongs to the technical field of hydrogel. According to the invention, 3, 4-dihydroxy benzaldehyde and gelatin are adopted as carbon sources, the synthesized nano-filler has amphiphilic surface characteristics, uniform dispersion of the nano-filler in a hydrogel network can be promoted, meanwhile, a mechanically firm and deformable nano-composite structure is established by utilizing the interaction of multivalent interfaces, and 3, 4-dihydroxy benzaldehyde and gelatin are added into the hydrogel network. The surface chemical property of the 1, 4-dihydroxybenzaldehyde / gelatin nano-filler not only can relieve phase separation, but also can promote synergistic energy dissipation through hydrogen bond reconstruction under the action of stress. According to the design, the inherent flexibility of the hydrogel is reserved, meanwhile, the electromechanical response capacity of the hydrogel is greatly improved, and the obtained hydrogel material has the dual functions of structural supporting and active sensing media and can be seamlessly integrated with biological tissue without sacrificing the fidelity of interface signals.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogel materials, and in particular relates to a method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel. Background Art

[0002] Traditional polymer hydrogels have attracted much attention in the field of flexible electronic devices due to their inherent compliance and easy processing. However, in practical applications, they are still limited by two inherent contradictions: first, the mechanical bearing capacity caused by the hydrated amorphous network is insufficient, which makes it difficult to meet the structural stability requirements under long-term cyclic loads; second, the low intrinsic conductivity caused by the charge transfer mechanism dominated by ion migration restricts the sensitivity of electrical signal response. Although carbon-based nanomaterials (such as carbon nanotubes and graphene) provide theoretical feasibility for optimizing hydrogel performance due to their excellent mechanical reinforcement effect and electronic conduction properties, there are still some key technical obstacles in the actual construction of high-performance nanocomposite systems: first, the nanoscale agglomeration phenomenon induced by the strong van der Waals interaction between nanofillers leads to micron-scale phase separation defects in the composite materials; second, the difference in chemical potential gradient between the hydrophobic surface of carbonaceous materials and the hydrophilic polymer matrix induces the interfacial stress concentration effect, significantly reducing the interfacial adhesion strength; third, the intrinsic rigidity characteristics of carbon-based nanofillers are mismatched with the elastic modulus of the flexible matrix, which will sacrifice the inherent flexibility of the matrix while improving the mechanical strength, forming a stiffness-flexibility inversion effect, which seriously limits its applicability in the field of dynamic flexible electronics. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, comprising the following steps:

[0006] Using 3,4-dihydroxybenzaldehyde and gelatin as raw materials and water as solvent, a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution is obtained through a hydrothermal reaction;

[0007] The 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution, acrylamide, a crosslinking agent and a photoinitiator are used as reactants to obtain the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel through free radical polymerization.

[0008] Technical principle:

[0009] The present invention uses 3,4-dihydroxybenzaldehyde and gelatin as carbon sources, and the synthesized nanofiller has amphiphilic surface characteristics, which can promote the uniform dispersion of nanofillers in the hydrogel network. At the same time, multivalent interface interactions, including dynamically reversible Schiff base connections and π-π stacking, are used to establish a mechanically strong and deformable nanocomposite structure. The surface chemical properties of 3,4-dihydroxybenzaldehyde / gelatin nanofillers can not only alleviate phase separation, but also promote synergistic energy dissipation through hydrogen bond reconstruction under stress. This synergistic design retains the inherent flexibility of the hydrogel while greatly improving its electromechanical response. The resulting hydrogel material has the dual functions of structural support and active sensing medium, and can be seamlessly integrated with biological tissues without sacrificing the fidelity of interface signals.

[0010] Furthermore, the mass ratio of the 3,4-dihydroxybenzaldehyde to gelatin is 1:1; and the volume ratio of the total mass of the 3,4-dihydroxybenzaldehyde and gelatin to water is 1:99 (g / mL).

[0011] Furthermore, the temperature of the hydrothermal reaction is 160° C., and the time of the hydrothermal reaction is 8 hours.

[0012] Furthermore, the mass ratio of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution to acrylamide is 4.5:2.5.

[0013] Furthermore, the mass ratio of the crosslinking agent to the photoinitiator is 1:10; and the amount of the crosslinking agent used is 0.12 wt % of the mass of acrylamide.

[0014] Furthermore, the polymerization reaction is carried out under ultraviolet light irradiation; the wavelength of the ultraviolet light is 365nm, and the irradiation power of the ultraviolet light is 2000W.

[0015] Furthermore, the polymerization reaction time is 5 minutes.

[0016] Furthermore, the crosslinking agent is MBA; and the photoinitiator is photoinitiator 1173.

[0017] The present invention provides a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel prepared by the preparation method described in the above technical scheme.

[0018] The present invention also provides the application of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel described in the above technical solution in the field of flexible electronic devices.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] The 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel provided by the present invention is prepared by using 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterials as nanofillers. The structural properties of 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterials (DGC) - nanoscale graphite framework, high crystallinity and amphiphilic surface chemistry, make DGC an ideal reinforcing agent for hydrogel composite materials, and its inherent water compatibility and defect-resistant structure make it possible to be synergistically integrated with polymer networks, solving the technical problem that existing hydrogels cannot synergistically improve mechanical strength, interfacial adhesion and conductivity.

[0021] The present invention synthesizes biomass carbon nanomaterials (DGC) by hydrothermal treatment of 3,4-dihydroxybenzaldehyde and gelatin. The nanomaterials have a unique triple synergistic structure: surface-exposed catechol groups that simulate the adhesion mechanism of marine mussels; a graphitized structural rigid core (including reversible Schiff base bonds, π-π stacking and hydrogen bond networks) for efficient load transfer through multivalent dynamic interface interactions; this design achieves synergistic enhancement of adhesion, toughness and mechanical strength in nanocomposite hydrogels.

[0022] The adhesive hydrogel provided by the invention has a simple preparation process and the prepared hydrogel has excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 The process schematic diagram of the preparation method of 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel in Example 1;

[0025] Figure 2 The stress-strain curves of the hydrogels prepared in Example 1 and Comparative Examples 1-3;

[0026] Figure 3 The stress-strain curves of the hydrogels prepared in Example 1 and Comparative Examples 4-7;

[0027] Figure 4 It is a bar graph of Young's modulus and toughness of the hydrogels prepared in Example 1 and Comparative Examples 1-3;

[0028] Figure 5 It is a bar graph of Young's modulus and toughness of the hydrogels prepared in Example 1 and Comparative Examples 4-7;

[0029] Figure 6 Graph showing the adhesion strength of the hydrogels prepared in Example 1 and Comparative Examples 1-3 on a glass substrate;

[0030] Figure 7 This is a graph showing the adhesion strength of the hydrogels prepared in Example 1, Comparative Example 2, Comparative Examples 4-7 and Comparative Examples 10-13 on a glass substrate;

[0031] Figure 8 DSC graphs of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2;

[0032] Fig. 9 Graph showing the adhesion strength of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 on a glass substrate at different humidity levels;

[0033] Fig.10 Graphs showing the adhesion strength of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 on a glass substrate in acidic and alkaline environments;

[0034] Fig.11 The conductivity diagram of the hydrogels prepared in Example 1 and Comparative Examples 4-7;

[0035] Fig.12 This is a comparison chart of the adhesion strength and tensile strength of the hydrogels prepared in Example 1 and Comparative Examples 8-9. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] The embodiment of the present invention provides a method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, comprising the following steps:

[0039] Using 3,4-dihydroxybenzaldehyde and gelatin as raw materials and water as solvent, a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution is obtained through a hydrothermal reaction;

[0040] The 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution, acrylamide, a crosslinking agent and a photoinitiator are used as reactants to obtain the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel through free radical polymerization.

[0041] In a preferred embodiment, the mass ratio of the 3,4-dihydroxybenzaldehyde to gelatin is 1:1; the volume ratio of the total mass of the 3,4-dihydroxybenzaldehyde and gelatin to water is 1:99 (g / mL). The present invention uses 3,4-dihydroxybenzaldehyde and gelatin as carbon sources, and the synthesized nanofiller has amphiphilic surface characteristics, introduces a large number of physical cross-linking reaction sites into the acrylamide hydrogel, and gives the hydrogel ultra-high tensile properties and adhesion properties.

[0042] In a preferred embodiment, the temperature of the hydrothermal reaction is 160° C. and the time of the hydrothermal reaction is 8 hours. In the present invention, the hydrothermal reaction is carried out at the above temperature, and the obtained 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial has excellent amphiphilic surface characteristics.

[0043] In a preferred embodiment, the mass ratio of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution to acrylamide is 4.5:2.5. The present invention controls the amount of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution within the above range, which is conducive to obtaining an adhesive hydrogel with excellent tensile and adhesive properties.

[0044] In a preferred embodiment, the mass ratio of the crosslinking agent to the photoinitiator is 1:10; and the amount of the crosslinking agent used is 0.12 wt % of the mass of acrylamide.

[0045] In a preferred embodiment, the polymerization reaction is carried out under ultraviolet light irradiation; the wavelength of the ultraviolet light is 365nm, and the irradiation power of the ultraviolet light is 2000W.

[0046] In a preferred embodiment, the polymerization reaction time is 5 minutes.

[0047] In a preferred embodiment, the crosslinking agent is MBA; the photoinitiator is photoinitiator 1173.

[0048] The present invention provides a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel prepared by the preparation method described in the above technical scheme.

[0049] The present invention also provides the application of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel described in the above technical solution in the field of flexible electronic devices.

[0050] The room temperature in the embodiments of the present invention refers to "25±2°C".

[0051] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0052] Example 1

[0053] A method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, the specific steps are as follows:

[0054] S1. Add 1 g of 3,4-dihydroxybenzaldehyde / gelatin (the mass ratio of 3,4-dihydroxybenzaldehyde to gelatin is 1:1) into 99 mL of deionized water, and then place it in a pressure-resistant reaction bottle and heat it to 160° C. for 8 h. After the reaction is completed, naturally cool it to room temperature to obtain a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution (DGC solution);

[0055] S2. Disperse 2.5 g of acrylamide AM, 3 mg of crosslinker MBA, 30 mg of photoinitiator 1173 and 3 g of deionized water into 4.5 g of the DGC solution prepared in step S1, and then ultrasonicate at 800 W for 7 min to obtain a mixed solution.

[0056] S3, use N 2 The mixed solution obtained in step S2 was degassed to remove oxygen, and then the mixed solution was quickly poured into a dumbbell-shaped polytetrafluoroethylene mold, and a polymerization reaction was carried out under 365nm ultraviolet radiation with an irradiation power of 2000W. After 5 minutes, a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel was obtained, which was recorded as 45%wtDGC / PAM hydrogel.

[0057] Comparative Example 1

[0058] A method for preparing a PAM hydrogel, the specific steps are as follows:

[0059] S1. Disperse 2.5 g acrylamide AM, 3 mg crosslinker MBA and 30 mg photoinitiator 1173 into 7.5 g deionized water, and then ultrasonicate at 800 W for 7 min to obtain a mixed solution.

[0060] S2, use N 2 The mixed solution obtained in step S2 was degassed to remove oxygen, and then the mixed solution was quickly poured into a dumbbell-shaped polytetrafluoroethylene mold, and a polymerization reaction was carried out under 365nm ultraviolet radiation with an irradiation power of 2000W. After 5 minutes, a PAM hydrogel was obtained.

[0061] Comparative Example 2

[0062] A method for preparing a DG / PAM hydrogel, the specific steps are as follows:

[0063] S1. Add 37.5 mg of gelatin and 37.5 mg of 3,4-dihydroxybenzaldehyde into 7.5 mL of deionized water and stir vigorously at 60° C. for 1 h to obtain a mixture solution.

[0064] S2. Disperse 2.5 g of acrylamide AM, 3 mg of crosslinker MBA and 30 mg of photoinitiator 1173 into 4.5 g of the mixture solution obtained in step S1, add 3 g of deionized water, and ultrasonicate at 800 W for 7 min to obtain a mixed solution.

[0065] S3, use N 2 The mixed solution obtained in step S2 was degassed to remove oxygen, and then the mixed solution was quickly poured into a dumbbell-shaped polytetrafluoroethylene mold, and a polymerization reaction was carried out under 365nm ultraviolet radiation with an irradiation power of 2000W. After 5 minutes, DG / PAM hydrogel was obtained.

[0066] Comparative Example 3

[0067] A method for preparing a D-CDs / PAM hydrogel, the specific steps are as follows:

[0068] S1. Add 1 g of 3,4-dihydroxybenzaldehyde to 99 g of deionized water, then place in a pressure-resistant reaction bottle and heat to 160° C. for 8 h. After the reaction is completed, cool naturally to room temperature to obtain a 3,4-dihydroxybenzaldehyde carbon dot solution (D-CDs solution).

[0069] S2. Add 4.5 g of the 3,4-dihydroxybenzaldehyde carbon dot solution obtained in step S1 to 3 g of deionized water, and then add 2.5 g of acrylamide AM, 3 mg of crosslinker MBA and 30 mg of photoinitiator 1173, and then ultrasonicate at 800 W for 7 min to obtain a mixed solution.

[0070] S3, use N 2 The mixed solution obtained in step S2 was degassed to remove oxygen, and then the mixed solution was quickly poured into a dumbbell-shaped polytetrafluoroethylene mold, and a polymerization reaction was carried out under 365nm ultraviolet radiation with an irradiation power of 2000W. After 5 minutes, D-CDs / PAM hydrogel was obtained.

[0071] Comparative Example 4

[0072] The difference from Example 1 is that in step S2, 2.5 g acrylamide AM, 3 mg crosslinker MBA, 30 mg photoinitiator 1173 and 6 g deionized water are dispersed into 1.5 g of the DGC solution prepared in step S1, and the rest is the same as Example 1 to obtain a 15 wt% DGC / PAM hydrogel.

[0073] Comparative Example 5

[0074] The difference from Example 1 is that in step S2, 2.5 g acrylamide AM, 3 mg crosslinker MBA, 30 mg photoinitiator 1173 and 5 g deionized water are dispersed into 2.5 g of the DGC solution prepared in step S1, and the rest is the same as Example 1 to obtain a 25 wt% DGC / PAM hydrogel.

[0075] Comparative Example 6

[0076] The difference from Example 1 is that in step S2, 2.5 g acrylamide AM, 3 mg crosslinker MBA, 30 mg photoinitiator 1173 and 4 g deionized water are dispersed into 3.5 g of the DGC solution prepared in step S1, and the rest is the same as Example 1 to obtain a 35 wt% DGC / PAM hydrogel.

[0077] Comparative Example 7

[0078] The difference from Example 1 is that in step S2, 2.5 g acrylamide AM, 3 mg crosslinker MBA, 30 mg photoinitiator 1173 and 2 g deionized water are dispersed into 5.5 g of the DGC solution prepared in step S1, and the rest is the same as Example 1 to obtain a 55 wt% DGC / PAM hydrogel.

[0079] Comparative Example 8

[0080] The difference from Example 1 is that, in step S1, 1 g of 3,4-dihydroxybenzaldehyde / gelatin (the mass ratio of 3,4-dihydroxybenzaldehyde to gelatin is 1:2) is added to 99 mL of deionized water, and then placed in a pressure-resistant reaction bottle and heated to 160° C. for reaction for 8 hours. After the reaction is completed, it is naturally cooled to room temperature to obtain a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution (DGC solution); the rest is the same as Example 1 to obtain a 3,4-D1 / Gel2 DGC / PAM hydrogel.

[0081] Comparative Example 9

[0082] The difference from Example 1 is that, in step S1, 1 g of 3,4-dihydroxybenzaldehyde / gelatin (the mass ratio of 3,4-dihydroxybenzaldehyde to gelatin is 2:1) is added to 99 mL of deionized water, and then placed in a pressure-resistant reaction bottle and heated to 160° C. for reaction for 8 hours. After the reaction is completed, it is naturally cooled to room temperature to obtain a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution (DGC solution); the rest is the same as Example 1 to obtain 3,4-D2 / Gel1 DGC / PAM hydrogel.

[0083] Comparative Examples 10-13

[0084] The difference from Comparative Example 2 is that in step S2, 2.5 g of acrylamide AM, 3 mg of crosslinker MBA and 30 mg of photoinitiator 1173 are respectively dispersed into 1.5 g (15 wt%, Comparative Example 10), 2.5 g (25 wt%, Comparative Example 11), 3.5 g (35 wt%, Comparative Example 12) and 5.5 g (45 wt%, Comparative Example 13) of the mixture obtained in step S1, and 6 g (Comparative Example 10), 5 g (Comparative Example 11), 4 g (Comparative Example 12) and 2 g (Comparative Example 13) of deionized water are respectively added, and then ultrasonicated at 800 W for 7 min to obtain a mixed solution; the rest is the same as Comparative Example 2.

[0085] Test example

[0086] Mechanical properties of the hydrogels prepared in Example 1 and Comparative Examples 1-7 were tested: The hydrogels prepared in Example 1 and Comparative Examples 1-7 were cut into rectangular specimens (4 cm × 2 mm × 1 mm) and subjected to tensile properties tests at room temperature. Uniaxial tensile measurements were performed using an electronic universal testing machine (Shenzhen Sun Technology Co., Ltd., China) at an extension speed of 80 mm / min. The test results are shown in Table 1. Figure 2-3 .

[0087] The toughness of the hydrogel was calculated based on the stress-strain curve. Figure 4-5 ; The calculation formula of toughness is:

[0088] ΔU=∫σε

[0089] Where ΔU is the toughness of the hydrogel, MJ / m 3 ; σ is the stress of hydrogel, kPa; ε is the strain of hydrogel, %.

[0090] The Young's modulus of the hydrogel was calculated based on the stress-strain curve. Figure 4-5 ; Among them, the calculation formula of Young's modulus is:

[0091]

[0092] Wherein, E is the Young's modulus of the hydrogel, kPa; Δσ is the stress change of the hydrogel, kPa; Δε is the strain change of the hydrogel, %.

[0093] The adhesion properties of the hydrogels prepared in Example 1 and Comparative Examples 1-7 were tested on a glass substrate with a size of 80 mm × 20 mm × 8 mm. The lap shear method was used to evaluate the adhesion properties of hydrogels of different types and hydrogels with different DGC contents. The experimental procedure and parameters are as follows: The hydrogel was cut into cubic blocks with a size of 20 mm × 20 mm × 1 mm. After applying it on the glass substrate, it was pressed manually for a few minutes. Subsequently, a lap shear test was performed using a mechanical testing machine. Three sets of tests were performed on each sample. During the test, no additional pressure was applied to the substrate after the lap shear test. The experiment was carried out using an ETM10B electromechanical universal testing machine (Shenzhen, China), in which each sample broke at a rate of 5 mm / min. The results are shown in Figure 6-7 .

[0094] Figure 2 : The stress-strain curves of the hydrogels prepared in Example 1 and Comparative Examples 1-3. Figure 2 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of the present invention can achieve a tensile strength of 470 kPa and a strain of more than 2200%, while the PAM hydrogel prepared in Comparative Example 1 has a tensile strength of about 150 kPa and a strain of about 1010%, the DG / PAM hydrogel prepared in Comparative Example 2 has a tensile strength of about 280 kPa and a strain of about 550%, and the D-CDs / PAM hydrogel prepared in Comparative Example 3 has a tensile strength of about 230 kPa and a strain of about 1050%.

[0095] Figure 3 The stress-strain curves of the hydrogels prepared in Example 1 and Comparative Examples 4-7 are shown in FIG. Figure 3 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of the present invention can achieve a tensile strength of 470 kPa and a strain of more than 2200%. Since the DGC content in the hydrogels of Comparative Examples 4-6 is lower than that in Example 1, the tensile strength and strain of the obtained hydrogels are decreased to varying degrees. The DGC content in the hydrogel prepared in Comparative Example 7 is higher than that in Example 1. Excessive DGC leads to a decrease in the compatibility between the carbon nanomaterial and the polymer interface, resulting in uneven dispersion, which further damages the integrity of the polymer network. Therefore, the tensile strength of the obtained hydrogel is reduced.

[0096] Figure 4 The Young's modulus and toughness of the hydrogels prepared in Example 1 and Comparative Examples 1-3 are shown in the figure. Figure 4 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of the present invention has the best toughness, which can reach 1.5 MJ / m 3 , significantly higher than Comparative Examples 1-3.

[0097] Figure 5The Young's modulus and toughness of the hydrogels prepared in Example 1 and Comparative Examples 4-7 are shown in the bar graph. Figure 5 It can be seen that the Young's modulus of the DGC / PAM hydrogel prepared in Example 1 of the present invention is the best, which can reach 20 kPa, significantly higher than that of Comparative Examples 4 to 7. At the same time, by comparing Example 1 with Comparative Examples 4 to 7, it can be seen that the toughness of the hydrogel increases with the increase of DGC content.

[0098] Figure 6 The adhesion strength of the hydrogels prepared in Example 1 and Comparative Examples 1-3 on the glass substrate is shown in FIG. Figure 6 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of the present invention has the highest adhesion strength on the glass substrate, which can reach more than 160 kPa, which is significantly higher than that of Comparative Examples 1-3.

[0099] Figure 7 The following is a graph showing the adhesion strength of the hydrogels prepared in Example 1, Comparative Example 2, Comparative Examples 4-7 and Comparative Examples 10-13 on a glass substrate. Figure 7 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of the present invention has the highest adhesion strength on the glass substrate, and the adhesion strength of the DGC / PAM hydrogel with DGC as filler shows a trend of first increasing and then decreasing with the increase of DGC content, and reaches the maximum when the DGC content is 45wt%, while the adhesion strength of the DG / PAM hydrogel with DG as filler shows a trend of first increasing and then tending to be flat with the increase of DGC content. In addition, when the DGC or DG content is 45wt% and 55wt%, the adhesion strength of the DGC / PAM hydrogel is significantly higher than that of the DG / PAM hydrogel.

[0100] Figure 8 The DSC graphs of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 are shown in FIG. Figure 8 It can be seen that compared with DG / PAM, the freezing point of DGC / PAM hydrogel is significantly lower (1.72°C), confirming the redistribution of water state - carbonization converts free water into bound water by strengthening hydrogen bonds, further illustrating that the tensile strength of DGC / PAM hydrogel is improved due to the strengthening effect of hydrogen bonds.

[0101] Fig. 9 The adhesion of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 at different humidity levels. Fig. 9 It can be seen that the increase in humidity impairs the contact between the hydrogel and the substrate interface, but at 94% RH, the DGC / PAM hydrogel still retains a strength of 24 kPa.

[0102] Fig.10The adhesion properties of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 in acid or alkaline environments. Fig.10 It can be seen that the adhesion strength of DGC / PAM hydrogel under acidic conditions (pH=3) is 28.6 kPa, and the adhesion strength under alkaline conditions (pH=10) is 17.8 kPa, showing acid-resistant or alkali-resistant adhesion performance, which is better than traditional catechol-based hydrogel adhesives that usually fail in extreme acid or alkaline environments.

[0103] Fig.11 The conductivity of the hydrogels prepared in Example 1 and Comparative Examples 4-7. Fig.11 The optimal charge transport properties at 45wt% DGC content were revealed, which were positively correlated with the tensile properties. This synergistic enhancement may originate from the microstructural advantages of the internal pore structure of the DGC / PAM hydrogel. In the 45wt% formulation, the material formed fine and uniformly distributed smooth pores, which promoted enhanced electron transport capabilities by establishing continuous conduction pathways while maintaining structural integrity. The simultaneous optimization of ion mobility and mechanical robustness indicates that there is a critical balance between charge carrier density and polymer network stability.

[0104] Fig.12 This is a comparison chart of the tensile strength and adhesion performance of the hydrogels prepared in Example 1 and Comparative Examples 8-9. In the figure, 3,4-D1 / Gel1 is Example 1, 3,4-D1 / Gel2 is Comparative Example 8, and 3,4-D2 / Gel1 is Comparative Example 9. Fig.12 The tensile strength and adhesion strength were revealed when the mass ratio of 3,4-dihydroxybenzaldehyde to gelatin was 1:2, 1:1, and 2:1, respectively. It can be seen that when the mass ratio of 3,4-dihydroxybenzaldehyde to gelatin is 1:1, the hydrogel has the best mechanical properties.

[0105] By comparing the experimental data of Example 1 and Comparative Examples 1-7, it can be seen that the hydrogel prepared in Example 1 of the present invention has the highest tensile strength and the best toughness, which can reach a tensile strength of 470kPa and a strain of more than 2200%, and has an adhesion strength of more than 160kPa (glass substrate lap shear). It can be seen from the data changes of Comparative Examples 4-7 that the mechanical properties of the hydrogel are gradually enhanced with the addition of DGC filler, indicating that we have achieved unprecedented mechanical tensile properties (strain>2200%) and strong adhesion (>160kPa) through a reasonable strategy. The hydrothermally synthesized DGC nanocarbon filler retains the inherent catechol molecules and can achieve spontaneous interfacial bonding through a variety of non-covalent interactions (hydrogen bonds, π-π stacking and coordination chemistry) without the need for external adhesive components.

[0106] The preparation method provided by the present invention solves the conflict between cohesive strength and adhesive performance in hydrogel systems. The carbonized network structure provides a graded modulus distribution that can simultaneously optimize fracture toughness (470kPa tensile strength) and interfacial energy dissipation. Unlike traditional hydrogel adhesives that rely on covalent grafting or physical entanglement, the hydrogel provided by the present invention achieves self-regulating adhesion through dynamic adhesive reconstruction and maintains structural integrity under cyclic mechanical loads.

[0107] The hydrogel provided by the present invention has scalable manufacturing procedures and environmental adaptability (pH 3-10 stability, 90% humidity tolerance), and is a multifunctional platform for the next generation of bio-integrated devices. Its capabilities in physiological signal monitoring and biomechanical energy harvesting have been demonstrated, indicating that the hydrogel provided by the present invention has the potential to fill the existing gaps in wearable healthcare technology.

[0108] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, characterized in that: The following steps are involved: Using 3,4-dihydroxybenzaldehyde and gelatin as raw materials and water as solvent, a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution is obtained through a hydrothermal reaction; The 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution, acrylamide, a crosslinking agent and a photoinitiator are used as reactants to obtain the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel through a polymerization reaction.

2. The preparation method according to claim 1, characterized in that: The mass ratio of the 3,4-dihydroxybenzaldehyde to gelatin is 1:1; the volume ratio of the total mass of the 3,4-dihydroxybenzaldehyde and gelatin to water is 1:99 (g / mL).

3. The preparation method according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 160° C., and the time of the hydrothermal reaction is 8 hours.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution to acrylamide is 4.5:2.

5.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the crosslinking agent to the photoinitiator is 1:10; the amount of the crosslinking agent used is 0.12wt% of the mass of acrylamide.

6. The preparation method according to claim 1, characterized in that: The polymerization reaction is carried out under ultraviolet light irradiation; the wavelength of the ultraviolet light is 365nm, and the irradiation power of the ultraviolet light is 2000W.

7. The preparation method according to claim 1, characterized in that: The polymerization reaction time is 5 min.

8. The preparation method according to claim 1 or 5, characterized in that: The crosslinking agent is MBA; the photoinitiator is photoinitiator 1173.

9. A 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel as claimed in claim 9 in the field of flexible electronic devices.

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