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

Abstract

The application discloses a preparation method of 3,4-dihydroxybenzaldehyde / gelatin carbon nano-material based adhesive hydrogel and belongs to the technical field of hydrogel. The application adopts 3,4-dihydroxybenzaldehyde and gelatin as carbon sources, the synthesized nano filler has amphiphilic surface characteristics, can promote the uniform dispersion of the nano filler in the hydrogel network, simultaneously utilizes the multivalent interface interaction to establish a mechanically solid and deformable nano composite structure, and the surface chemical properties of the 3,4-dihydroxybenzaldehyde / gelatin nano filler can not only relieve phase separation, but also promote synergistic energy dissipation through hydrogen bond reconstruction under stress. The design retains the inherent flexibility of the hydrogel, simultaneously greatly improves the electromechanical response capacity of the hydrogel, the obtained hydrogel material has the dual functions of structural support and active sensing medium, can be seamlessly integrated with biological tissues, and does not sacrifice the fidelity of the interface signal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogel materials, and particularly relates to a preparation method of 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel. BACKGROUND

[0002] Traditional polymer hydrogels are concerned in the field of flexible electronic devices due to their inherent compliance and easy processability. However, they are still limited in practical applications by two inherent contradictions: firstly, the mechanical bearing capacity is insufficient due to the hydrated amorphous network, which is difficult to meet the demand for structural stability under long-term cyclic loading; secondly, the low intrinsic conductivity caused by the ion migration dominated charge transport mechanism restricts the response sensitivity of electrical signals. Although carbon-based nanomaterials (such as carbon nanotubes and graphene) provide theoretical feasibility for the performance optimization of hydrogels due to their excellent mechanical enhancement effect and electronic conduction characteristics, there are still some key technical obstacles in the actual construction of high-performance nanocomposite systems: firstly, the nanoscale agglomeration phenomenon induced by strong van der Waals interaction between nanofillers leads to micron-scale phase separation defects in the composite material; secondly, the chemical potential gradient difference between the hydrophobic surface of carbon-based materials and the hydrophilic polymer matrix causes interfacial stress concentration effect, which significantly reduces the interfacial adhesion strength; thirdly, the inherent rigidity characteristics of carbon-based nanofillers and the mismatch of elastic modulus of the flexible matrix will sacrifice the inherent flexibility of the matrix while improving the mechanical strength, forming a rigidity-flexibility inversion effect, which seriously limits its application boundary in the field of dynamic flexible electronics. SUMMARY

[0003] To solve the above technical problems, the application provides a preparation method of 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel.

[0004] To achieve the above purpose, the application provides the following technical scheme:

[0005] The application provides a preparation method of 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, which comprises the following steps:

[0006] 3,4-dihydroxybenzaldehyde and gelatin are used as raw materials, water is used as a solvent, and 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, and a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel is obtained through a free radical polymerization reaction.

[0008] Technical principle:

[0009] The application adopts 3,4-dihydroxybenzaldehyde and gelatin as carbon sources, and the synthesized nanofiller has amphiphilic surface characteristics, which can promote the uniform dispersion of the nanofiller in the hydrogel network, and the mechanical solid and deformable nanocomposite structure is established by using multivalent interface interaction, including dynamic reversible Schiff base connection and π-π stacking, and the surface chemical properties of the 3,4-dihydroxybenzaldehyde / gelatin nanofiller can not only alleviate phase separation, but also promote synergistic energy dissipation by hydrogen bond reconstruction under stress. This synergistic design retains the inherent flexibility of the hydrogel, while greatly improving the electromechanical response capability of the hydrogel, and the obtained 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 the interface signal.

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

[0011] Further, the temperature of the hydrothermal reaction is 160 DEG C, and the time of the hydrothermal reaction is 8h.

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

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

[0014] Further, 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] Further, the time of the polymerization reaction is 5min.

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

[0017] The application provides a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel prepared by the preparation method.

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

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

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

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

[0022] The adhesive hydrogel provided by this invention has a simple preparation process and the prepared hydrogel has excellent properties. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

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

[0025] Figure 2 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 are shown.

[0027] Figure 4 The bar chart shows the Young's modulus versus toughness of the hydrogels prepared in Example 1 and Comparative Examples 1-3.

[0028] Figure 5 The bar chart shows the Young's modulus versus toughness of the hydrogels prepared in Example 1 and Comparative Examples 4-7.

[0029] Figure 6 The adhesion strength diagram of the hydrogels prepared in Example 1 and Comparative Examples 1-3 on the glass substrate is shown.

[0030] Figure 7 The adhesion strength diagram of the hydrogels prepared in Example 1, Comparative Example 2, Comparative Examples 4-7 and Comparative Examples 10-13 on the glass substrate is shown.

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

[0032] Figure 9 The adhesion strength diagrams of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 on glass substrates under different humidity conditions are shown.

[0033] Figure 10 The adhesion strength diagrams of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 on glass substrates under acidic and alkaline environments.

[0034] Figure 11 The conductivity diagrams are for the hydrogels prepared in Example 1 and Comparative Examples 4-7.

[0035] Figure 12 The graph shows a comparison of the adhesion strength and tensile strength of the hydrogels prepared in Example 1 and Comparative Examples 8-9. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] This 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 was obtained through a hydrothermal reaction.

[0040] Using the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution, acrylamide, crosslinking agent, and photoinitiator as reactants, a free radical polymerization reaction was carried out to obtain the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel.

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

[0042] In a preferred embodiment, the hydrothermal reaction temperature is 160°C, and the hydrothermal reaction time is 8 hours. The hydrothermal reaction performed at the above temperature yields 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterials with superior 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. By controlling the amount of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution within the above range, this invention facilitates the preparation of 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; the amount of the crosslinking agent 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 365 nm and the irradiation power of the ultraviolet light is 2000 W.

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

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

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

[0049] This 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] In this embodiment of the invention, room temperature refers to "25±2℃".

[0051] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0052] Example 1

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

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

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

[0056] S3. Degas the mixed solution obtained in step S2 with N2 to remove oxygen, and then quickly pour the mixed solution into a dumbbell-shaped polytetrafluoroethylene mold. Polymerize under 365nm ultraviolet light irradiation with a power of 2000W. After 5 minutes, 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel is obtained, denoted as 45%wtDGC / PAM hydrogel.

[0057] Comparative Example 1

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

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

[0060] S2. Degas the mixed solution obtained in step S2 with N2 to remove oxygen, and then quickly pour the mixed solution into a dumbbell-shaped polytetrafluoroethylene mold. Polymerize under 365nm ultraviolet light irradiation with an irradiation power of 2000W. After 5 minutes, PAM hydrogel is obtained.

[0061] Comparative Example 2

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

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

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

[0065] S3. Degas the mixed solution obtained in step S2 with N2 to remove oxygen, and then quickly pour the mixed solution into a dumbbell-shaped polytetrafluoroethylene mold. Polymerize under 365nm ultraviolet light irradiation with an irradiation power of 2000W. After 5 minutes, DG / PAM hydrogel is obtained.

[0066] Comparative Example 3

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

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

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

[0070] S3. Degas the mixed solution obtained in step S2 with N2 to remove oxygen, and then quickly pour the mixed solution into a dumbbell-shaped polytetrafluoroethylene mold. Polymerize under 365nm ultraviolet light irradiation with an irradiation power of 2000W. After 5 minutes, D-CDs / PAM hydrogel is obtained.

[0071] Comparative Example 4

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

[0073] Comparative Example 5

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

[0075] Comparative Example 6

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

[0077] Comparative Example 7

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

[0079] Comparative Example 8

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

[0081] Comparative Example 9

[0082] The difference from Example 1 is that in step S1, 1g of 3,4-dihydroxybenzaldehyde / gelatin (the mass ratio of 3,4-dihydroxybenzaldehyde to gelatin is 2:1) was added to 99mL of deionized water, and then placed in a pressure-resistant reaction flask and heated to 160°C for 8h. After the reaction was completed, it was naturally cooled to room temperature to obtain a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution (DGC solution); the rest is the same as in 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, 2.5g of acrylamide AM, 3mg of crosslinking agent MBA and 30mg of photoinitiator 1173 were dispersed into 1.5g (15wt%, Comparative Example 10), 2.5g (25wt%, Comparative Example 11), 3.5g (35wt%, Comparative Example 12) and 5.5g (45wt%, Comparative Example 13) of the mixture obtained in step S1, respectively. 6g (Comparative Example 10), 5g (Comparative Example 11), 4g (Comparative Example 12) and 2g (Comparative Example 13) of deionized water were added respectively, and the mixtures were sonicated at 800W for 7min to obtain mixed solutions; the rest was the same as Comparative Example 2.

[0085] Test case

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

[0087] The toughness of the hydrogel was calculated based on the stress-strain curve, and the results are shown in [see figure]. Figures 4-5 The formula for calculating toughness is:

[0088] ΔU=∫σε

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

[0090] The Young's modulus of the hydrogel was calculated based on the stress-strain curve, and the results are shown in [Figure number missing]. Figures 4-5 The formula for calculating Young's modulus is as follows:

[0091]

[0092] In the formula, E is the Young's modulus of the hydrogel, kPa; Δσ is the stress change of the hydrogel, kPa; and 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 glass substrates with dimensions of 80 mm × 20 mm × 8 mm. The adhesion properties of different types of hydrogels and hydrogels with different DGC contents were evaluated using the lap shear test. The experimental procedure and parameters are as follows: The hydrogel was cut into cubic blocks with dimensions of 20 mm × 20 mm × 1 mm. After being applied to the glass substrate, it was manually pressed for several minutes. Subsequently, an lap shear test was performed using a mechanical testing machine. Three sets of tests were conducted for each sample. No additional pressure was applied to the substrate after the lap shear test. The experiment was conducted using an ETM10B electromechanical universal testing machine (Shenzhen, China), where each sample broke at a rate of 5 mm / min. The results are shown in [Figure number missing]. Figures 6-7 .

[0094] Figure 2 The stress-strain curves are for 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 over 2200%, while the tensile strength of the PAM hydrogel prepared in Comparative Example 1 is about 150 kPa and the strain is about 1010%, the tensile strength of the DG / PAM hydrogel prepared in Comparative Example 2 is about 280 kPa and the strain is about 550%, and the tensile strength of the D-CDs / PAM hydrogel prepared in Comparative Example 3 is about 230 kPa and the strain is about 1050%.

[0095] Figure 3 The stress-strain curves are for the hydrogels prepared in Example 1 and Comparative Examples 4-7. Figure 3 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of this invention can achieve a tensile strength of 470 kPa and a strain of over 2200%. In Comparative Examples 4-6, the DGC content in the hydrogels was lower than that in Example 1, and the tensile strength and strain of the hydrogels obtained were reduced to varying degrees. In Comparative Example 7, the DGC content in the hydrogel was higher than that in Example 1. The excessive DGC led to a decrease in the compatibility between the carbon nanomaterial and the polymer interface, resulting in uneven dispersion and further damaging the integrity of the polymer network. Therefore, the tensile strength of the hydrogel obtained was reduced.

[0096] Figure 4 The bar chart shows the Young's modulus versus toughness of the hydrogels prepared in Example 1 and Comparative Examples 1-3. From... Figure 4 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of this invention has the best toughness, reaching 1.5 MJ / m. 3 The value was significantly higher than that of the control group 1-3.

[0097] Figure 5Bar graphs showing the Young's modulus versus toughness of the hydrogels prepared in Examples 1 and Comparative Examples 4-7. From... Figure 5 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of this invention has the best Young's modulus, reaching 20 kPa, which is significantly higher than that of Comparative Examples 4-7. Meanwhile, a comparison between Example 1 and Comparative Examples 4-7 shows that the toughness of the hydrogel increases with increasing DGC content.

[0098] Figure 6 This is a graph showing the adhesion strength of the hydrogels prepared in Example 1 and Comparative Examples 1-3 on glass substrates. 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, reaching more than 160 kPa, which is significantly higher than that of Comparative Examples 1-3.

[0099] Figure 7 This is a graph showing the adhesion strength of the hydrogels prepared in Examples 1, 2, 4-7, and 10-13 on glass substrates. Figure 7 It can be seen that the DGC / PAM hydrogel prepared in Example 1 of this invention exhibits the highest adhesion strength on the glass substrate. Furthermore, the adhesion strength of the DGC / PAM hydrogel with DGC as filler first increases and then decreases with increasing DGC content, reaching its maximum at a DGC content of 45 wt%. In contrast, the adhesion strength of the DG / PAM hydrogel with DG as filler first increases and then tends to level off with increasing DGC content. Moreover, at DGC or DG contents of 45 wt% and 55 wt%, the adhesion strength of the DGC / PAM hydrogel is significantly higher than that of the DG / PAM hydrogel.

[0100] Figure 8 DSC images of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2. From... Figure 8 It can be seen that the freezing point of DGC / PAM hydrogel is significantly lower (1.72℃) compared with DG / PAM, which confirms 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 hydrogen bond enhancement effect.

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

[0102] Figure 10The adhesive properties of the DGC / PAM hydrogel prepared in Example 1 and the DG / PAM hydrogel prepared in Comparative Example 2 under acidic or alkaline environments. Figure 10 It can be seen that the DGC / PAM hydrogel has an adhesion strength of 28.6 kPa under acidic conditions (pH=3) and 17.8 kPa under alkaline conditions (pH=10), exhibiting acid- or alkali-resistant adhesion properties, which are superior to traditional catechol-based hydrogel adhesives that typically fail under extreme acid or alkali conditions.

[0103] Figure 11 The conductivity is the electrical conductivity of the hydrogels prepared in Example 1 and Comparative Examples 4-7. Figure 11 The optimal charge transport properties at a DGC content of 45 wt% were revealed, showing a positive correlation with tensile properties. This synergistic enhancement likely stems from the microstructural advantages of the internal pore structure of the DGC / PAM hydrogel. In the 45 wt% formulation, the material forms finely and uniformly distributed smooth pores, promoting enhanced electron transport capabilities by establishing continuous conduction pathways while maintaining structural integrity. Simultaneous optimization of ion mobility and mechanical robustness indicates a crucial balance between charge carrier density and polymer network stability.

[0104] Figure 12 The figure shows a comparison of the tensile strength and adhesion properties 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. Figure 12 The tensile and adhesive strengths of the hydrogels with mass ratios of 3,4-dihydroxybenzaldehyde and gelatin of 1:2, 1:1, and 2:1 were revealed. It can be seen that the hydrogel has the best mechanical properties when the mass ratio of 3,4-dihydroxybenzaldehyde and gelatin is 1:1.

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

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

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

[0108] The above are merely preferred embodiments 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 scope of the technology 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 method for preparing a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel, characterized in that, Includes the following steps: Using 3,4-dihydroxybenzaldehyde and gelatin as raw materials and water as solvent, a 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution was obtained through a hydrothermal reaction. Using the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial solution, acrylamide, crosslinking agent, and photoinitiator as reactants, a polymerization reaction was carried out to obtain the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel.

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

3. The preparation method according to claim 1, characterized in that, The hydrothermal reaction was carried out at a temperature of 160°C for 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 is 0.12 wt% 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 takes 5 minutes.

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. The application of the 3,4-dihydroxybenzaldehyde / gelatin carbon nanomaterial-based adhesive hydrogel as described in claim 9 in the field of flexible electronic devices.

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