Method for the preparation of polyacid-based polyzwitterionic gel materials for additive manufacturing and the gel materials thereof
By initiating the photopolymerization of polyacid-based zwitterionic gels with photoinitiators and combining it with LCD photocuring technology, the problems of complex preparation process and low efficiency have been solved, enabling the efficient preparation of gel materials with excellent performance and expanding their application range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2025-09-16
- Publication Date
- 2026-07-28
AI Technical Summary
The existing preparation process of polyacid-based zwitterionic gels is complex, has a long reaction time, low production efficiency, and cannot prepare gels with complex shapes, which limits their application in multifunctional flexible electronic devices.
Using raw materials such as polyoxometalates, zwitterionic compounds, imidazole ionic liquids, water-soluble monomers and crosslinking agents, and adding photoinitiators, a gel is formed through photoinitiated polymerization, and additive manufacturing is carried out using LCD photocuring technology.
The preparation process has been simplified and production efficiency has been improved, enabling the preparation of gel materials with excellent mechanical and electrochemical properties, thus broadening their application prospects in additive manufacturing, flexible sensors, and biomedicine.
Smart Images
Figure CN120818099B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new colloidal chemical materials technology, specifically to a method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing and the gel material thereof. Background Technology
[0002] Photopolymerization is an important branch of 3D printing technology, which utilizes a specific light source to selectively cure liquid photosensitive resin, building up layers one by one. Among these, liquid crystal display (LCD) photopolymerization is one of the most widely adopted photopolymerization 3D printing methods in recent years. LCD photopolymerization technology uses a high-power ultraviolet LED array as the light source, and a liquid crystal display (LCD) as a dynamic mask to precisely control the light pattern. The molding material used is primarily liquid photosensitive resin. During printing, a transparent release film (such as FEP or PDMS) is first placed at the bottom of the resin tank, which is then filled with sufficient resin. The printing platform is immersed to a depth of one layer below the resin surface. The ultraviolet LED light source is located below the LCD. With each layer printed, the LCD instantly switches to the corresponding light-shielding pattern based on the slice cross-section information. Ultraviolet light passes through the transparent area of the LCD and illuminates the release film, precisely curing the resin layer in contact with it. After one layer is cured, the printing platform rises to a height equal to the thickness of one layer, causing the cured layer to detach from the release film. Fresh liquid resin then flows and fills the gap again. The platform then descends to a new height, the LCD screen switches to the next layer pattern, and the UV LED light source illuminates the surface again for curing. This process is repeated until all layers are cured. After printing, the model is removed from the platform, uncured resin is cleaned from the surface, and a UV post-curing treatment is usually required to further improve the model's final mechanical properties. Developing mature process materials is a key issue that urgently needs to be addressed.
[0003] Polyacid-based zwitterionic gels possess excellent mechanical properties and high electrical conductivity. Previous preparation methods involved copolymerizing hydrophilic monomers acrylamide (AM) and [2-(methacryloxy)ethyl]dimethyl(3-sulfopropyl)ammonium hydroxide (SBMA) in an aqueous solution containing 1-ethyl-methylimidazolium sulfate (EMIM-ES) and K6[P2W18O62]·14H2O (P2W18) via a one-pot random copolymerization process and a "lock-in" mechanism. This method suffers from drawbacks such as complex preparation processes, long reaction times, low production efficiency, and the inability to produce gels with complex shapes, limiting the application of polyacid-based zwitterionic gels in multifunctional and integrated flexible electronic devices. Unlike previous studies that used temperature-initiated copolymerization to prepare hydrogels, the polyacid-based zwitterionic material required in this invention needs to be photoinitiated to form a gel, thus necessitating the addition of a photoinitiator. Photoinitiators can absorb energy of a certain wavelength in the ultraviolet (250-420nm) or visible (400-800nm) region, generate free radicals, and thus initiate monomer polymerization, crosslinking and curing. Summary of the Invention
[0004] To address the technical problems of complex preparation processes, long reaction times, low production efficiency, and inability to produce gels with complex shapes in existing technologies, this invention provides a method for preparing multi-acid-based zwitterionic gel materials for additive manufacturing, as well as the gel material itself.
[0005] To achieve the above objectives, the main technical solutions adopted by the present invention include: A method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing includes the following steps: Step 1: Disperse the polyoxometalate in a dispersant using ultrasonic bath, and denote it as material A; Step 2: Add zwitterionic compounds and imidazole ionic liquids to material A, and obtain material B by ultrasonication in a water bath; Step 3: Add water-soluble monomers to material B and sonicate in a water bath to obtain material C; Step 4: Add a photoinitiator to material C and obtain material D by ultrasonication in a water bath; Step 5: Add a crosslinking agent to material D and use water bath ultrasound to obtain a polyacid-based zwitterionic gel material for printing.
[0006] Preferably, in step 1, the polyoxometalate is H2P2W18; and the dispersant is deionized water.
[0007] Preferably, in step 2, the zwitterionic compound is 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, i.e. sulfonate betaine methacrylate (SBMA); and the imidazole ionic liquid is 1-ethyl-3-methylimidazolium sulfate ethyl salt (EMIM-ES).
[0008] Preferably, in step 3, the water-soluble monomer is acrylamide (AM).
[0009] Preferably, in step 4, the photoinitiator includes, but is not limited to, ethyl 2,4,6-trimethylbenzoylphosphonate (Tpo-L).
[0010] Preferably, in step 5, the crosslinking agent includes, but is not limited to, polyethylene glycol diacrylate (PEGDA).
[0011] Preferably, in step 1, the ratio of H2P2W18 to dispersant is 0.0625 ~ 0.1875:1, in g: ml.
[0012] Preferably, in step 2, the ratio of zwitterionic compound to imidazole ionic liquid is 0.35:1 (g:ml), and the imidazole ionic liquid is added at a volume ratio of 4:1 to the dispersant in step 1; in step 3, the water-soluble monomer is added at a molar ratio of 3:1 to the zwitterionic compound in step 2; in step 4, the photoinitiator is added at a volume ratio of 0.05 to 0.0625:1 to the dispersant in step 1; and in step 5, the crosslinking agent is added at a volume ratio of 0.125:1 to the dispersant in step 1.
[0013] Preferably, in steps 1 to 5, the water bath ultrasonic power is 80 kHz and the water bath ultrasonic temperature is 19 to 25 °C.
[0014] A multi-acid-based zwitterionic gel material for additive manufacturing is prepared by the above-described preparation method.
[0015] The beneficial effects of this invention are: The present invention provides a method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing. The equipment used is simple and the operation is easy. The prepared multi-acid-based zwitterionic gel material can form a gel material with excellent mechanical and electrochemical properties under ultraviolet light irradiation. The application of this material in selective area light transmission technology photocuring printing process has been successfully developed by using an LCD photocuring printer. The method of this invention is the first to apply polyacid-based zwitterionic gel material to additive manufacturing. The printed polyacid-based zwitterionic gel material has excellent mechanical and electrochemical properties, and the prepared material has good application prospects in materials, flexible sensors, and biomedicine. Initiating the copolymerization reaction of polyacid-based zwitterionic gel materials with ultraviolet light can expand the application range of these materials. Achieving additive manufacturing of these materials through LCD photocuring is of great significance for the manufacturing process and practical application of polyacid-based zwitterionic gel materials. Attached Figure Description
[0016] Figure 1 Flowchart for the preparation of polyacid-based zwitterionic gel materials; Figure 2 Stress-strain curves of polyacid-based zwitterionic gel materials under different strain loading and unloading conditions; Figure 3 Stress-strain curves of polyacid-based zwitterionic gel material after 200 cycles of loading and unloading at 70% strain. Figure 4 The impedance change curves of polyacid-based zwitterionic gel materials after 10 cycles of loading and unloading under different strains are shown. Figure 5 This is a schematic diagram of the principle of LCD photopolymerization printing; where... Figure 5 (a) is a schematic diagram of the principle of gel photocuring printing, in which... Figure 5 (b) A schematic diagram illustrating the principle of preparing for the next layer of gel photocuring printing. Figure 5 (c) To display the printed pattern of a single gel layer during photopolymerization printing, Figure 5 (d) refers to the compounds contained in the ink (excluding H2O); Figure 6 Different shapes of multi-acid-based zwitterionic gel material samples were formed by LCD photopolymerization printing; among them Figure 6 (a) is a support structure, in which Figure 6 (b) is the emblem of Jilin University, in which Figure 6 (c) is a cube structure, in which Figure 6 (d) is a hemispherical array structure. Detailed Implementation
[0017] The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings, so as to fully understand how the present invention uses technical means to solve technical problems and achieve technical effects and to implement it accordingly.
[0018] The preparation process of thermally initiated polyacid-based zwitterionic gels is complex, has a long reaction time, low production efficiency, and cannot produce gels with complex shapes, thus limiting their applications. The principle of this invention is to use polyoxometalates (including but not limited to H2P2W18), zwitterionic compounds (3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, i.e. sulfonate betaine methacrylate (SBMA)), imidazole ionic liquids (1-ethyl-3-methylimidazolium sulfate ethyl salt (EMIM-ES)), water-soluble monomers (acrylamide (AM)), and crosslinking agents (including but not limited to polyethylene glycol diacrylate (PEGDA)) as raw materials, and introduce photoinitiators (including but not limited to ethyl 2,4,6-trimethylbenzoylphosphonate (Tpo-L)). The photoinitiators can absorb energy of a certain wavelength in the ultraviolet light region (250-420nm) or the visible light region (400-800nm) to generate free radicals, thereby initiating monomer polymerization, crosslinking and curing to form a gel material, which can be additively manufactured using selective area light transmission technology. The present invention introduces a photoinitiator, which can endow the polyacid-based zwitterionic gel with photoinduced molding properties, making it possible for 3D printing, providing another favorable processing method for the material, and broadening its application prospects.
[0019] To better explain and facilitate understanding of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. SBMA, EMIM-ES, AM, PEGDA, and Tpo-L were all purchased from Aladdin Reagent Network.
[0020] The typical ink manufacturing process is as follows: Add 50 mg H2P2W18 to 0.4 mL of deionized water and sonicate in a 21°C water bath for 1 minute. Then, add 0.5587 g SBMA and 1.6 mL EMIM-ES and sonicate in a 21°C water bath for 20 seconds. Add 0.4265 g AM to the above solution and sonicate in a 21°C water bath for 1 minute. Add 20 μL of photoinitiator Tpo-L and sonicate in a 21°C water bath for 30 seconds. Finally, add 50 μL of PEGDA as a crosslinking agent to the mixture and sonicate in a 21°C water bath for 30 seconds to prepare a polyacid-based zwitterionic gel material, i.e., printing ink.
[0021] Printer parameters and printing parameter settings: To ensure successful printing, the printing platform parameters need to be adjusted. The single-layer illumination time affects the longitudinal curing depth; excessive illumination time leads to over-curing and gel deformation, while insufficient illumination time results in a too-soft gel or failure to form. When the gel is transparent, the single-layer illumination time also affects residual ink on the printed structure, causing it to solidify and leading to gel deformation, making it impossible to print complex structures. Therefore, an appropriate single-layer illumination time must be set. The initial layer illumination time and the number of initial layers affect whether the gel can adhere to the platform. Appropriate illumination time and layers must be selected to ensure the gel remains fixed on the platform during printing and can be easily removed after printing. The time it takes for the UV lamp to illuminate after the platform descends to its designated position is called the pre-illumination waiting time for each layer. The platform's lifting and lowering speeds, along with the pre-illumination waiting time for each layer, affect the formation of air bubbles within the gel; slower speeds and longer waiting times result in a lower probability of air bubble formation. Different inks have different curing times under the same UV light, so parameters need to be adjusted according to the specific properties of the ink.
[0022] The printing platform measures 108 mm × 108 mm × 155 mm, with an LCD screen achieving a horizontal accuracy of 0.1 mm and a vertical accuracy of 0.025 mm. The UV lamp has a wavelength of 405 nm and a power of 10 W. The printing platform parameters were adjusted to suit the properties of typical polyacid-based zwitterionic gel inks. The single-layer illumination time was set to 15 s, the initial layer illumination time to 25 s, the initial number of layers to 2, the platform lifting and lowering speed to 5 mm / s, and the waiting time before each layer's illumination to 2 s.
[0023] Add 10mL of the prepared printing ink to the printer ink tank. Create a 10mm×10mm×10mm cube using computer modeling. Use ChiTuBox slicing software to slice the cube and upload the graphic data of each slice to the printer. Print according to the parameters described above.
[0024] The printed sample was removed and irradiated under an 80W UV lamp for 10 seconds. Mechanical properties were tested using a pressure testing machine to obtain stress-strain curves under different strain loading and unloading cycles, as well as stress-strain curves after 200 cycles of loading and unloading at 70% strain. The compression speed of the compression disc was 5 mm / min, and the lifting and restoring speed was 5 mm / min. A new sample was then taken and electrochemical properties were tested using a pressure testing machine and an electrochemical workstation to obtain impedance change curves after 10 cycles of loading and unloading under different strains.
[0025] The present invention involves mechanical performance testing on a universal testing machine (ZQ 950B) and electrochemical performance testing on an electrochemical workstation 660E (Shanghai Chenhua).
[0026] The above operation process is as follows: Figure 1 As shown, the stress-strain curves under different strain loading and unloading conditions are as follows: Figure 2 As shown, the loading and unloading stress-strain curves within 85% strain exhibit good overlap during loading, demonstrating the strong stability of the gel. The narrow area between the loading and unloading curves proves its high elasticity.
[0027] Figure 3 The figure shows the stress-strain curves after 200 cycles of loading and unloading at 70% strain. As shown in the figure, after 200 cycles of loading and unloading at 70% strain, the gel stress-strain curves did not show significant drift or fluctuation, proving that it has high mechanical durability.
[0028] Figure 4 The impedance change curves are obtained after 10 loading and unloading cycles with different strains. The gel impedance shows a stable range of change for both large and small strains, demonstrating its potential as a piezoresistive sensor.
[0029] Figure 5 The printing principle involves using a bottom-up LCD 3D printer that applies 405nm wavelength ultraviolet light to print ink. Figure 5 This diagram illustrates the process of printing one layer of ionogel. Before printing the next layer, the platform for attaching the already printed gel structure descends. Once in position, as shown... Figure 5 (a) The ultraviolet LED lights up, and the LCD screen displays the mask image of the current layer, such as... Figure 5 As shown in (c), transparent pixels allow ultraviolet light to pass through, while black pixels block the light. After a period of exposure, the layer is printed, the ultraviolet lamps are turned off, the LCD screen returns to its light-blocking state, and the platform rises a certain distance, causing the cured layer to detach from the release film at the bottom of the resin tank. This process is repeated until the entire model is printed.
[0030] Figure 6 This is a sample print demonstration. Using the prepared multi-acid-based zwitterionic gel, various complex two-dimensional and three-dimensional gel structures can be easily fabricated. Printing accuracy can be further improved by using a higher resolution LCD printer or a high-precision SLA / DLP printer. Figure 6 (a) shows the printed scaffold structure, validating the ability to print three-dimensional structures. Figure 6 (b) A printed version of the Jilin University logo is shown to demonstrate the high printability of complex geometry. Figure 6 (c) shows the printed cube structure. Figure 6 (d) shows the printed hemispherical array structure.
Claims
1. A method for preparing polyacid-based zwitterionic gel materials for additive manufacturing, characterized in that: Includes the following steps: Step 1: Disperse the polyoxometalate in a dispersant using ultrasonic bath, and denote it as material A; Step 2: Add zwitterionic compounds and imidazole ionic liquids to material A, and obtain material B by ultrasonication in a water bath; Step 3: Add water-soluble monomers to material B and sonicate in a water bath to obtain material C; Step 4: Add a photoinitiator to material C and obtain material D by ultrasonication in a water bath; Step 5: Add a crosslinking agent to material D and perform ultrasonication in a water bath to obtain a method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing; In step 1, the polyoxometalate is H2P2W18; the dispersant is deionized water; In step 2, the zwitterionic compound is 3-[N,N-dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]ammonium]propane-1-sulfonic acid inner salt, i.e., sulfonate betaine methacrylate; the imidazole ionic liquid is 1-ethyl-3-methylimidazolium sulfate ethyl salt.
2. The method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing according to claim 1, characterized in that: In step 3, the water-soluble monomer is acrylamide.
3. The method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing according to claim 1, characterized in that: In step 4, the photoinitiator is ethyl 2,4,6-trimethylbenzoylphosphonate.
4. The method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing according to claim 1, characterized in that: In step 5, the crosslinking agent is polyethylene glycol diacrylate.
5. The method for preparing a polyacid-based zwitterionic gel material for additive manufacturing according to claim 2, characterized in that: In step 1, the ratio of H2P2W18 to dispersant is 0.0625 ~ 0.1875:1, in g: ml.
6. The method for preparing a polyacid-based zwitterionic gel material for additive manufacturing according to claim 1, characterized in that: In step 2, the ratio of zwitterionic compound to imidazole ionic liquid is 0.35:1 (g:ml), and the imidazole ionic liquid is added at a volume ratio of 4:1 to the dispersant in step 1. In step 3, the water-soluble monomer is added at a molar ratio of 3:1 to the zwitterionic compound in step 2; the photoinitiator is added at a volume ratio of 0.05 to 0.0625:1 to the dispersant in step 1. In step 5, the crosslinking agent is added at a volume ratio of 0.125:1 to the dispersant in step 1.
7. The method for preparing a multi-acid-based zwitterionic gel material for additive manufacturing according to claim 1, characterized in that: In steps 1 to 5, the water bath ultrasonic power is 80 kHz and the water bath ultrasonic temperature is 19 to 25 ℃.
8. A multi-acid-based zwitterionic gel material for additive manufacturing, characterized in that: The gel material is a gel material prepared by the method according to any one of claims 1 to 7.