A photopolymerizable 3D printed multifunctional conductive elastomer, its preparation method and application

Abstract

This invention discloses a photopolymerizable 3D-printed multifunctional conductive elastomer, its preparation method, and its applications. The photopolymerizable 3D-printed multifunctional conductive elastomer of this invention comprises a eutectic solvent and a high-polymerization-efficiency photoinitiator. The eutectic solvent includes hydrogen bond acceptors and hydrogen bond donors, with the hydrogen bond donors including polymeric hydrogen bond donors participating in the polymerization reaction and non-polymeric hydrogen bond donors not participating in the polymerization reaction. Through improvements to the eutectic solvent and research on photopolymerizable resins, this invention produces a conductive elastomer with good mechanical properties, which is expected to be applied in the fields of physical sensing, electronic skin, and soft robotics, promoting the rapid development of related industries.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, and in particular relates to a photopolymerizable 3D printing multifunctional conductive elastomer, its preparation method, and its application research. Background Technology

[0002] With the continuous development of the information society, the era of the Internet of Things is rapidly advancing. Flexible electronic devices have received widespread attention and use. Due to their excellent mechanical flexibility, flexible electronic devices have gradually gained popularity and entered a period of rapid development. They have been widely applied in wearable devices, transistors, displays, sensors, actuators, and energy storage devices, breaking through many areas where traditional rigid electronic devices cannot be used. In the future intelligent era, flexible electronic devices will play an even greater role, inevitably impacting human production and lifestyles in all aspects. However, electronic devices with only flexible and bendable properties cannot meet people's needs; conductive elastomers that can adapt to various mechanical deformations and maintain excellent electrical properties during deformation are more competitive. Furthermore, the preparation of various conductive elastomer materials with special structures is currently a research hotspot.

[0003] Photopolymer 3D printing technology, as a material preparation method for designable structures, has already made significant progress in the field of elastomer printing. However, single flexible devices are no longer sufficient to meet the needs of modern development; therefore, we need to further design traditional elastomers to endow them with functional properties. Currently, most conductive elastomers are prepared by adding conductive fillers to a matrix resin. However, the high cost of conductive fillers and their poor dispersion in the matrix resin lead to certain problems in their application.

[0004] Polymerization eutectic solvents are applications derived from eutectic solvents, achieved by selecting hydrogen bond donors with polymerization capabilities. Studies have shown the potential of polymerization eutectic solvents in photopolymerization, but challenges remain in the fabrication of complex structures, such as human organ models.

[0005] Meanwhile, photoinitiators are required in photopolymer 3D printing. Among existing photoinitiators, TPO has been reported by the EU to be toxic and is about to be banned; BAPO's excessively high initiation efficiency may lead to incomplete cross-linking in the system, and the cured material often yellows. Finding a new and high-performance photoinitiator is one of the urgent problems to be solved in the field of photopolymer 3D printing. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a photopolymerizable 3D-printed multifunctional conductive elastomer, its preparation method, and its applications. By improving the eutectic solvent and researching the photopolymerizable resin, this invention develops a conductive elastomer with good electrical conductivity, structural designability, and good mechanical properties. Furthermore, the preparation process is simple, reducing production costs. The prepared conductive elastomer holds promise for applications in physical sensing, electronic skin, and soft robotics, promoting the rapid development of related industries.

[0007] The technical solution of the present invention is as follows:

[0008] The present invention first protects a polymeric eutectic solvent, wherein the polymeric eutectic solvent includes hydrogen bond acceptors and hydrogen bond donors, wherein the hydrogen bond donors include polymeric hydrogen bond donors that participate in the polymerization reaction and non-polymeric hydrogen bond donors that do not participate in the polymerization reaction; wherein the molar ratio of hydrogen bond acceptors to polymeric hydrogen bond donors in the polymeric eutectic solvent is 1:0.5-2.5.

[0009] Furthermore, the hydrogen bond acceptor includes one or more of choline chloride, tetrabutylammonium chloride, tetrabutylammonium bisulfate, and tetrabutylammonium acetate.

[0010] Furthermore, the non-polymeric hydrogen bond donor is phytic acid; the polymeric hydrogen bond donor is acrylic acid.

[0011] Furthermore, the non-polymerized hydrogen bond donor accounts for 0.5-20 wt% of the total mass of the hydrogen bond acceptor and the polymerized hydrogen bond donor.

[0012] Furthermore, the preparation method of the polymeric eutectic solvent is as follows: after mixing the hydrogen bond acceptor and the polymeric hydrogen bond donor, stir at 50-80°C for 1-5 hours, add the non-polymeric hydrogen bond donor, and react at 50-80°C for 1-5 hours.

[0013] This invention also protects a photocurable 3D printing multifunctional conductive elastomer, which is prepared by photocuring a mixture of the aforementioned eutectic solvent, crosslinking agent, and initiator.

[0014] This invention also protects a method for preparing the aforementioned photopolymerizable 3D printed multifunctional conductive elastomer, the method being as follows:

[0015] Preparation of the aforementioned eutectic solvent: namely, mixing the hydrogen bond acceptor and the polymeric hydrogen bond donor and stirring at 50-80°C for 1-5 hours, adding the non-polymeric hydrogen bond donor, and reacting at 50-80°C for 1-5 hours;

[0016] The crosslinking agent and photoinitiator are added to the eutectic solvent for polymerization and mixed to obtain a 3D printing resin solution;

[0017] Place the 3D printing resin liquid into the 3D printer, set the program, and print to obtain a photocurable 3D printed multifunctional conductive elastomer.

[0018] Furthermore, the light intensity of the 3D printer is 1-5 mW·cm². -1 The 3D printer has a single-layer printing thickness of 50µm and a single-layer printing time of 5-10s.

[0019] Further, the crosslinking agent accounts for 0.5-2 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor, and the photoinitiator accounts for 0.5-0.7 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor.

[0020] Further, the crosslinking agent includes at least one of polyethylene glycol diacrylate and polyethylene glycol dimethacrylate, wherein the number average molecular weight of the crosslinking agent is 200-600.

[0021] Furthermore, the photoinitiator is 2,4,6-(trimethylbenzoyl)di-p-tolylphosphine oxide.

[0022] The beneficial technical effects of this invention are as follows:

[0023] This invention uses a polymeric eutectic solvent as the raw material for 3D printing conductive elastomers, combined with layered curing 3D printing, to control the thickness of a single layer to 50 micrometers or 100 micrometers. The heat release during each photocuring is controlled. At the same time, by using a polymeric eutectic solvent instead of pure acrylic acid, the problem of excessive heat generation during direct photocuring of acrylic bulk polymerization leading to defects in the cured product is avoided.

[0024] Furthermore, this invention prepares a conductive elastomer with antibacterial and bactericidal properties by mixing the non-polymerized hydrogen bond donor phytic acid with other hydrogen bond donors and acceptors, providing a direction for the application of polymeric eutectic solvents in the field of medical elastic materials. Simultaneously, the photoinitiator used in this invention has better initiation efficiency than existing photoinitiators, avoiding the shortcomings of traditional photoinitiators such as incomplete crosslinking or toxicity.

[0025] This invention utilizes a polymeric eutectic solvent and a photoinitiator with high initiation efficiency to prepare an elastomer that not only possesses excellent tensile properties and thermal stability but also good ionic conductivity. Furthermore, compared to elastomers that are directly photocured, the elastomer prepared by 3D printing in this invention can be customized according to customer needs and can be used without assembling with other elastic materials, while still exhibiting good sensitivity under a small range of strain (10%-40%).

[0026] The method for preparing 3D printed conductive elastomers provided by this invention uses a low-toxicity, low-cost polymeric eutectic solvent as the solvent, avoiding the problem of poor dispersibility and thus poor performance that may be caused by adding fillers. At the same time, the preparation process of this invention is simple, and the resulting conductive elastomer can be directly applied to human motion detection. Moreover, its structure has rich scalability and can meet customized needs. Attached Figure Description

[0027] Figure 1 The effects of different photoinitiators and different TMO contents on the initiation efficiency of the PEDS system were investigated.

[0028] Figure 2 The tensile-deformation curves of ion-conductive elastomers prepared for application examples and comparative application examples of the present invention are shown.

[0029] Figure 3 Cyclic tensile curves of ion-conducting elastomers prepared for application examples and comparative application examples of the present invention under 100% deformation.

[0030] Figure 4 Conductivity tests of ion-conducting elastomers prepared for application examples and comparative application examples of the present invention.

[0031] Figure 5 The following is a SEM (Scanning Electron Microscopy) analysis of the ion-conducting elastomer prepared for application examples and comparative application example 1 of the present invention.

[0032] Figure 6 Bacterial experiments were conducted using the 3D ion-conductive elastomer prepared in Example 1 of this invention.

[0033] Figure 7 The sensing performance of the 3D ion-conductive elastomer prepared in Application Example 1 of this invention is tested.

[0034] Among them: a) Rotation process sensing test; b) Bending process sensing test; c) Tension process sensing test; d) Small strain range sensing test; e) Finger movement monitoring; f) Sensing test after freezing at -10℃ for 24 hours. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] A polymeric eutectic solvent, the polymeric eutectic solvent comprising hydrogen bond acceptors and hydrogen bond donors, the hydrogen bond donors comprising polymeric hydrogen bond donors participating in the polymerization reaction and non-polymeric hydrogen bond donors not participating in the polymerization reaction.

[0037] In one embodiment of the present invention, the molar ratio of hydrogen bond acceptor to polymeric hydrogen bond donor in the eutectic solvent is 1:0.5, 1:1.5, 1:2.0 or 1:2.5.

[0038] In one embodiment of the present invention, the hydrogen bond acceptor includes one or more of choline chloride, tetrabutylammonium chloride, tetrabutylammonium bisulfate, and tetrabutylammonium acetate.

[0039] In one embodiment of the present invention, the non-polymeric hydrogen bond donor is phytic acid; the polymeric hydrogen bond donor is acrylic acid, and the addition of phytic acid can provide antibacterial properties to the conductive elastomer.

[0040] In one embodiment of the present invention, the non-polymerized hydrogen bond donor accounts for 0.5 wt%, 5 wt%, 10 wt%, 15 wt%, or 20 wt% of the total mass of the hydrogen bond acceptor and the polymerized hydrogen bond donor.

[0041] In one embodiment of the present invention, the method for preparing the polymeric eutectic solvent is as follows: after mixing the hydrogen bond acceptor and the polymeric hydrogen bond donor, the mixture is stirred at 50°C, 60°C, 70°C or 80°C for 1 h, 3 h, 4 h or 5 h, a non-polymeric hydrogen bond donor is added, and the mixture is reacted at 50°C, 60°C, 70°C or 80°C for 1 h, 3 h, 4 h or 5 h.

[0042] This invention also protects a photocurable 3D printing multifunctional conductive elastomer, which is prepared by photocuring a mixture of the aforementioned eutectic solvent, crosslinking agent, and initiator.

[0043] This invention also protects a method for preparing the aforementioned photopolymerizable 3D printed multifunctional conductive elastomer, the method being as follows:

[0044] Preparation of the aforementioned eutectic solvent for polymerization: namely, mixing hydrogen bond acceptor and polymeric hydrogen bond donor and stirring at 50-80℃ for 1-5h, adding non-polymeric hydrogen bond donor, and reacting at 50℃, 60℃ or 80℃ for 1h, 2h, 4h or 5h.

[0045] The crosslinking agent and photoinitiator are added to the eutectic solvent for polymerization and mixed to obtain a 3D printing resin solution;

[0046] Place the 3D printing resin liquid into the 3D printer, set the program, and print to obtain a photocurable 3D printed multifunctional conductive elastomer.

[0047] In one embodiment of the present invention, the light intensity of the 3D printer is 1-5 mW·cm. -1 The 3D printer has a single-layer printing thickness of 50µm and a single-layer printing time of 5-10s.

[0048] In one embodiment of the present invention, the crosslinking agent accounts for 0.5 wt%, 1 wt%, or 2 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor, and the photoinitiator accounts for 0.5 wt%, 0.55 wt%, or 0.6 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor.

[0049] In one embodiment of the present invention, the crosslinking agent includes at least one of polyethylene glycol diacrylate and polyethylene glycol dimethacrylate, wherein the number average molecular weight of the crosslinking agent is 200-600.

[0050] In one embodiment of the present invention, the photoinitiator is 2,4,6-(trimethylbenzoyl)di-p-tolylphosphine oxide. Compared with existing photoinitiators, the photoinitiator used in the present invention not only does not produce toxicity, but also has higher photoinitiation efficiency.

[0051] Example 1

[0052] A polymeric eutectic solvent and a 3D-printed ion-conductive elastomer prepared therefrom are disclosed. The preparation methods of the polymeric eutectic solvent and the 3D-printed ion-conductive elastomer are as follows:

[0053] (1) Stir 10g of hydrogen bond acceptor choline chloride and 10.332g of polymeric hydrogen bond donor acrylic acid at 65°C for 2h until clear and transparent; add 0.8g of phytic acid solution dropwise to the polymeric eutectic solvent and stir at 65°C for 2h until a polymeric eutectic solvent is formed.

[0054] (2) Preparation of 3D printing resin solution: 0.20g of polyethylene glycol dimethacrylate, 0.12g of 2,4,6(trimethylbenzoyl)di-p-tolylphosphine oxide and eutectic solvent were mixed evenly and stirred for 0.5h to obtain a prepolymer solution, wherein the number average molecular weight of polyethylene glycol dimethacrylate was 400.

[0055] In this embodiment, the molar ratio of choline chloride to acrylic acid is 1:2. The amount of phytic acid added is 4 wt%.

[0056] Example 2

[0057] A polymeric eutectic solvent and a 3D-printed ion-conductive elastomer prepared therefrom are disclosed. The preparation methods of the polymeric eutectic solvent and the 3D-printed ion-conductive elastomer are as follows:

[0058] (1) Stir 10g of hydrogen bond acceptor choline chloride and 10.332g of polymeric hydrogen bond donor acrylic acid at 65°C for 2h until clear and transparent; add 1.6g of phytic acid solution dropwise to the polymeric eutectic solvent and stir at 65°C for 2h until a polymeric eutectic solvent is formed.

[0059] (2) Preparation of 3D printing resin solution: 0.20g of polyethylene glycol dimethacrylate, 0.12g of 2,4,6(trimethylbenzoyl)di-p-tolylphosphine oxide and eutectic solvent were mixed evenly and stirred for 0.5h to obtain a prepolymer solution, wherein the number average molecular weight of polyethylene glycol dimethacrylate was 400.

[0060] In this embodiment, the molar ratio of choline chloride to acrylic acid is 1:2. The amount of phytic acid added is 8 wt%.

[0061] Example 3

[0062] A polymeric eutectic solvent and a 3D-printed ion-conductive elastomer prepared therefrom are disclosed. The preparation methods of the polymeric eutectic solvent and the 3D-printed ion-conductive elastomer are as follows:

[0063] (1) Stir 10g of hydrogen bond acceptor choline chloride and 10.332g of polymeric hydrogen bond donor acrylic acid at 65°C for 2h until clear and transparent; add 2.4g of phytic acid solution dropwise to the polymeric eutectic solvent and stir at 65°C for 2h until a polymeric eutectic solvent is formed.

[0064] (2) Preparation of 3D printing resin solution: 0.20g of polyethylene glycol dimethacrylate, 0.12g of 2,4,6(trimethylbenzoyl)di-p-tolylphosphine oxide and eutectic solvent were mixed evenly and stirred for 0.5h to obtain a prepolymer solution, wherein the number average molecular weight of polyethylene glycol dimethacrylate was 400.

[0065] In this embodiment, the molar ratio of choline chloride to acrylic acid is 1:2. The amount of phytic acid added is 12 wt%.

[0066] Example 4

[0067] A polymeric eutectic solvent and a 3D-printed ion-conductive elastomer prepared therefrom are disclosed. The preparation methods of the polymeric eutectic solvent and the 3D-printed ion-conductive elastomer are as follows:

[0068] (1) At a molar ratio of 1:0.5, 1 hydrogen bond acceptor choline chloride and polymeric hydrogen bond donor acrylic acid were stirred at 50°C for 1 h until clear and transparent; phytic acid solution (phytic acid accounts for 0.5 wt% of the total mass of hydrogen bond acceptor and polymeric hydrogen bond donor) was added dropwise to the polymeric eutectic solvent and stirred at 50°C for 1 h until a polymeric eutectic solvent was formed.

[0069] (2) Preparation of 3D printing resin solution: According to the crosslinking agent accounting for 0.5wt% of the total mass of hydrogen bond acceptor and polymer hydrogen bond donor, and the photoinitiator accounting for 0.5% of the total mass of hydrogen bond acceptor and polymer hydrogen bond donor, polyethylene glycol dimethacrylate, 2,4,6(trimethylbenzoyl)di-p-tolylphosphine oxide and polymer eutectic solvent are mixed evenly and stirred for 0.5h to obtain a prepolymer solution, wherein the number average molecular weight of polyethylene glycol dimethacrylate is 400.

[0070] Example 5

[0071] A polymeric eutectic solvent and a 3D-printed ion-conductive elastomer prepared therefrom are disclosed. The preparation methods of the polymeric eutectic solvent and the 3D-printed ion-conductive elastomer are as follows:

[0072] (1) At a molar ratio of 1:2.5, 1 hydrogen bond acceptor choline chloride and polymeric hydrogen bond donor acrylic acid were stirred at 80°C for 5 h until clear and transparent; phytic acid solution (phytic acid accounts for 20 wt% of the total mass of hydrogen bond acceptor and polymeric hydrogen bond donor) was added dropwise to the polymeric eutectic solvent and stirred at 80°C for 5 h until a polymeric eutectic solvent was formed.

[0073] (2) Preparation of 3D printing resin solution: The crosslinking agent accounts for 2 wt% of the total mass of hydrogen bond acceptor and polymer hydrogen bond donor, and the photoinitiator accounts for 0.7% of the total mass of hydrogen bond acceptor and polymer hydrogen bond donor. Polyethylene glycol dimethacrylate, 2,4,6-(trimethylbenzoyl)di-p-tolylphosphine oxide and the eutectic solvent for polymerization are mixed evenly and stirred for 0.5 h to obtain a prepolymer solution. The number average molecular weight of polyethylene glycol dimethacrylate is 400.

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing a polymeric eutectic solvent and its ionic conductive elastomer. The difference between this method and Example 1 is that phytic acid solution is not added in step (1). A polymeric eutectic solvent with a phytic acid content of 0 wt% is prepared, and the amounts of choline chloride, acrylic acid, photoinitiator, and crosslinking agent added are kept consistent with those in the example.

[0076] Comparative Example 2

[0077] Same as Example 1, except that the photoinitiator used is BAPO.

[0078] Comparative Example 3

[0079] Same as Example 1, except that the photoinitiator used is TPO.

[0080] Comparative Example 4

[0081] Similar to Example 1, except that the amount of photoinitiator used is 0.2 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor in this comparative example.

[0082] Comparative Example 5

[0083] Similar to Example 1, except that in this comparative example, the photoinitiator accounts for 0.4 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor.

[0084] Comparative Example 6

[0085] Similar to Example 1, except that in this comparative example, the photoinitiator accounts for 0.8 wt% of the total mass of the eutectic solvent used in polymerization.

[0086] Comparative Example 7

[0087] Similar to Example 1, except that in this comparative example, the photoinitiator accounts for 1.0 wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor.

[0088] Application Examples 1-3:

[0089] Application Examples 1-3 correspond to Examples 1-3. The 3D printing resin liquid prepared in Examples 1-3 is placed into a 3D printer for printing. Specifically, it is a photopolymerizable 3D printed conductive elastomer, prepared as follows: the eutectic solvent from Examples 1-3 is placed into the feed tank of a DLP printer, and a 3D printing model is selected for printing. The single-layer printing thickness of the photopolymerizable 3D printer is 50 μm, the base layer curing time is 15 s, and the curing time for the remaining single layers is 5 s.

[0090] Comparative application example 1:

[0091] Comparing Application Example 1 with Comparative Example 1, the 3D printing resin liquid prepared in Comparative Example 1 was placed into a 3D printer for printing. Specifically, a photopolymerizable 3D printed conductive elastomer was prepared by placing the polymerizable eutectic solvent from Comparative Example 1 into the feed tank of a DLP printer and selecting a 3D printing model for printing. The single-layer printing thickness of the photopolymerizable 3D printer was 50 μm, the curing time of the base layer was 15 s, and the curing time of the remaining single layers was 5 s.

[0092] Test example:

[0093] (1) Comparison of initiation efficiency of different photoinitiators

[0094] The photoinitiation efficiency of 3D printing resin solutions prepared with different photoinitiators BAPO, TPO, and TMO at different 405nm absorption wavelengths and with different TMO contents was tested, and characterized by Photo-DSC and real-time infrared spectroscopy, respectively. The results are as follows: Figure 1As shown in the figure, TMO has a higher initiation efficiency than TPO and even surpasses BAPO, while avoiding the inherent defects of both TPO and BAPO, making it a highly efficient photoinitiator in PEDS photopolymerization systems. For different initiator contents, the final conversion rate is slightly higher at 0.2 wt% than at 0.6 wt%, but the time required for complete curing is too long, failing to meet the requirements of rapid 3D printing. Therefore, considering both curing time and double bond conversion rate, the optimal overall initiation efficiency is achieved when TMO accounts for 0.6 wt% of the total mass of the eutectic solvent.

[0095] (2) Tensile property test

[0096] Tensile tests were conducted on the 3D-printed conductive elastomers prepared in Application Examples 1-3 and Comparative Application Example 1. The results are as follows: Figure 2 As shown, from Figure 2 It can be seen that in the absence of phytic acid, the material exhibits a ductile tensile curve and relatively high macroscopic hardness. With the increase of phytic acid content, the non-covalent cross-linking within the system increases, making the material softer while the tensile strength decreases, but the elongation at break significantly increases.

[0097] (3) Elongation at break test

[0098] The 3D-printed conductive elastomers prepared in Application Examples 1-3 and Comparative Application Example 1 were subjected to 5 cycles of tensile testing at 100% deformation. The results are as follows: Figure 3 As shown, with the increase of phytic acid content, the non-covalent cross-linking in the system increases, the material becomes softer, the elongation at break is significantly improved, and the resilience of the material is greatly enhanced.

[0099] (4) Conductivity test

[0100] Conductivity tests were performed on the 3D-printed conductive elastomers prepared in Application Examples 1-3 and Comparative Application Example 1. The results are as follows: Figure 4 As shown, with the addition of phytic acid, the interaction between ammonium salts and hydroxyl groups in the system is enhanced, leading to increased ion migration. This is manifested as an increase in electrical conductivity.

[0101] Meanwhile, the 3D-printed conductive elastomers provided in Examples 1-3 and Comparative Example 1 were analyzed by scanning electron microscopy. Figure 5 The magnification was 4k times. Specifically, the sample was freeze-dried for 24 hours, and then its cross-sectional morphology was observed using liquid nitrogen brittle fracture. The results showed that the elastomer fracture interface was smooth and riddled with pores, which facilitate ion migration. Furthermore, the pore radius increased with increasing phytic acid content, confirming the improved conductivity.

[0102] (5) Antibacterial test

[0103] The antibacterial properties of the 3D-printed conductive elastomer provided in Application Example 1 were tested using the following method:

[0104] First, weigh out 2.5g of tryptone, 1.25g of yeast extract, and 2.5g of sodium chloride and dissolve them in 250mL of distilled water to prepare a liquid culture medium. At the same time, weigh out 2.5g of tryptone, 1.25g of yeast extract, 4.5g of agar powder, and 2.5g of sodium chloride and dissolve them in 250mL of distilled water to prepare a solid culture medium. Sterilize both in a high-temperature and high-pressure steam sterilizer at 121℃ for 30 minutes and set aside for later use.

[0105] The second step involves taking three 12mL bacterial culture tubes, adding 5mL of LB liquid medium to each, and then adding 20μL of a single colony of *E. coli* and a single colony of *Staphylococcus aureus* to each. After shaking well, dilute 10⁻⁶. 3 The culture medium was placed in a constant temperature shaker (25℃, 200rpm) and incubated for 12 hours. Simultaneously, 2 ml of solid culture medium was added to the culture dish and evenly spread. After cooling, the mixture, along with the 3D-printed conductive elastomer prepared in Example 1, was sterilized by irradiation under a UV lamp for 12 hours before use.

[0106] The third step is to dilute the cultured bacteria again by 10%. 2 The sterilized samples (1cm*1cm*1mm) were placed in centrifuge tubes and diluted bacterial culture solution was added. The blank group served as the control group. The samples were incubated in a constant temperature shaker (37℃, 200rpm) for 12 hours.

[0107] Fourth step: Take 100 μL of the diluted bacterial solution and spread it evenly on the solid culture medium. Place it in a constant temperature incubator at 25℃ for 10 hours, take pictures and record the results.

[0108] The results are as follows Figure 6 As shown in the figure, in the control group without the conductive elastomer for sterilization, bacteria grew densely in the culture medium. However, after the bacteria were sterilized by soaking in the conductive elastomer, the number of Escherichia coli colonies was significantly reduced, and Staphylococcus aureus colonies were not even clearly visible. This result indicates that the material has good antibacterial ability.

[0109] (6) Sensor performance test

[0110] The 3D-printed conductive elastomer provided in Application Example 1 was used to test its sensing performance using methods such as tension, torsion, and extrusion. The results are as follows: Figure 7 As shown in the figure: a) Rotation process sensing test; b) Bending process sensing test; c) Tension process sensing test; d) Small strain range sensing test; e) Finger movement monitoring; f) Sensing test after freezing at -10℃ for 24 hours.

[0111] The specific method is as follows:

[0112] The 3D-printed conductive elastomer prepared in Application Example 1 was connected to the circuit of a multimeter, which continuously monitored its resistance changes. In Figure 'ad', the resistance changes were recorded after horizontal stretching, bilateral bending, and 180° twisting of the dumbbell-shaped spline. In Figure 'e', ​​the printed finger model was directly worn on the finger, and the multimeter recorded the resistance changes after bending the finger to different degrees. Figure 'f' shows the tensile sensing performance test performed on the elastomer after being placed in a -10°C environment for 24 hours, following the same steps as the tensile test described above.

[0113] Depend on Figure 7 As can be seen, the 3D-printed conductive elastomer provided in Application Example 1 did not break during the experiment, and the strain signals it transmitted were clear. This indicates that the 3D-printed conductive elastomer has good sensing sensitivity.

[0114] This application combines 3D printing technology with polymer eutectic solvents to prepare conductive elastomers with customizable structures and excellent performance.

[0115] Compared to traditional photocurable resin systems, polymeric eutectic solvents have lower viscosity and higher transparency, and do not suffer from filler dispersion issues. Furthermore, initiators traditionally used in photocurable 3D printing have been adapted to the applications of existing photocurable 3D printing elastomers, resulting in conductive elastomers with good electrical conductivity, structural designability, and good mechanical properties. The manufacturing process is also simple, reducing production costs.

[0116] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that are directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A method for preparing a photocured 3D printed multifunctional conductive elastomer, characterized in that, The preparation method is as follows: The hydrogen bond acceptor and the polymeric hydrogen bond donor are mixed and stirred at 50-80℃ for 1-5h, the non-polymeric hydrogen bond donor is added, and the reaction is carried out at 50-80℃ for 1-5h to prepare the polymeric deep eutectic solvent; The crosslinking agent and the photoinitiator are added to the polymeric deep eutectic solvent, mixed, and a 3D printing resin liquid is obtained; The 3D printing resin liquid is placed in a 3D printer, a program is set, and printing is carried out to obtain a photocured 3D printing multifunctional conductive elastomer; The light intensity of the 3D printer is 1-5 mW·cm -1 The single-layer printing thickness of the 3D printer is 50 um, and the single-layer printing time is 5-10 s; The polymeric deep eutectic solvent comprises a hydrogen bond acceptor and a hydrogen bond donor, the hydrogen bond donor comprises a polymeric hydrogen bond donor participating in the polymerization reaction and a non-polymeric hydrogen bond donor not participating in the polymerization reaction; in the polymeric deep eutectic solvent, the molar ratio of the hydrogen bond acceptor to the polymeric hydrogen bond donor is 1:2.0-2.5; The hydrogen bond acceptor is choline chloride; The non-polymeric hydrogen bond donor is phytic acid, and the polymeric hydrogen bond donor is acrylic acid; The non-polymeric hydrogen bond donor accounts for 0.5-20wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor. The photoinitiator is 2,4,6-(trimethylbenzoyl)di-p-tolylphosphine oxide, and the photoinitiator accounts for 0.5-0.7wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor.

2. The production method according to claim 1, characterized by, The crosslinking agent accounts for 0.5-2wt% of the total mass of the hydrogen bond acceptor and the polymeric hydrogen bond donor.

3. The preparation method according to claim 1, characterized in that, The crosslinking agent comprises at least one of polyethylene glycol diacrylate and polyethylene glycol dimethacrylate, wherein the number average molecular weight of the crosslinking agent is 200-600.

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