Bionic "brick-mud" structure super-strong and super-tough chitosan membrane and preparation method thereof

Abstract

The application discloses a kind of biomimetic " brick-mud " structure superstrong super tough chitosan membrane and preparation method thereof, it is related to biomimetic nacre material technical field.The biomimetic material imitates natural nacre " brick-mud " structure, including but not limited to the following raw materials: chitosan, boron nitride (or ferroferric oxide nanosheet, carbon nitride, graphene, etc.), tannin, sericin.The preparation steps include: 1) tannin solution is mixed with boron nitride (or ferroferric oxide nanosheet, carbon nitride, graphene, etc.) solution;2) chitosan solution is fixed on table type glue machine by vacuum suction;3) the mixed solution obtained in step 1 is measured by pipette, drop into the chitosan solution being rotated, then sericin solution is measured by pipette and dropped into mold, and the morphology and performance of the material are controlled by setting different rotating speeds;4) natural air drying, to obtain chitosan membrane.Compared with traditional materials, the biomimetic chitosan membrane prepared by the application has the advantages of high strength, high toughness, degradability and no pollution, which makes up for the shortcomings of existing biomimetic materials, such as weak mechanical properties and large structural defects.

Description

Technical Field

[0001] This invention relates to the field of biomimetic mother-of-pearl materials technology, specifically to a biomimetic "brick-mud" structured ultra-strong and ultra-tough chitosan membrane and its preparation method. Background Technology

[0002] With plastic waste pollution becoming increasingly severe, the world generates over 300 million tons of plastic waste annually, of which only 9% is recycled. Microplastics have entered the food chain, posing a serious threat to ecosystems and human health. The market demand for green, biodegradable, and high-performance materials is becoming increasingly urgent.

[0003] Currently, traditional bio-based materials still face three major technical bottlenecks: insufficient strength, poor toughness, and weak water resistance, making it difficult to meet the needs of practical applications. Although some studies have attempted to improve material performance through biomimetic structural design, such as using cellulose nanofibers and TiO2 to coat mica to prepare high-strength biomimetic composite materials, or using nacre-like structural design to improve the fracture toughness of alumina-based ceramics, these systems mostly involve inorganic reinforcing phases or complex sintering processes, making it difficult to simultaneously achieve all-natural components, green preparation, and excellent mechanical properties.

[0004] Mother-of-pearl (the nacreous layer of seashells) possesses a classic "brick-and-mortar" multi-level structure, composed of alternating layers of aragonite flakes (bricks) and an organic matrix (mortar), exhibiting both high strength and high toughness. Its toughening mechanisms include crack deflection, brick slippage, and organic matrix bridging, providing an ideal template for the design of high-performance biomimetic materials. However, currently, biomimetic mother-of-pearl structures prepared from all-natural components through simple solution assembly are still very scarce. Therefore, developing a biomimetic material that combines high strength, high toughness, good water resistance, and is entirely renewable has significant research value and application prospects. Summary of the Invention

[0005] This invention provides a biomimetic "brick-mud" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, aiming to solve the technical problems of low strength, poor toughness and weak water resistance of existing bio-based materials.

[0006] The biomimetic chitosan membrane of this invention uses chitosan as the matrix material, tannic acid to construct a dynamic cross-linked network, two-dimensional boron nitride nanosheets as the rigid reinforcing phase, and sericin as the interface toughening agent. Through a multi-level "brick-and-mortar" structure design mimicking nacre, it achieves a synergistic improvement in both high strength and high toughness. Specifically, the rigid nanosheets act as "bricks" to provide mechanical support, the flexible polymer matrix acts as "mortar" to transfer loads and inhibit crack propagation, and the multi-level structure effectively dissipates energy through mechanisms such as crack deflection and interface debonding.

[0007] To achieve the above-mentioned technical objectives, the present invention mainly adopts the following technical solutions: This invention provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, comprising the following steps: Step 1: Prepare chitosan, boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.), tannic acid, and sericin to specific solution concentrations.

[0008] Step 2: Mix boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) with tannic acid solution.

[0009] Step 3: Add the mixture to the chitosan solution and add the sericin solution.

[0010] Step 4: Air dry naturally to obtain the chitosan membrane.

[0011] In a preferred embodiment of the present invention, step 1 involves a method for preparing a concentration solution of the raw material: Step 1.1: Add an aqueous acetic acid solution to the chitosan powder to dissolve it, thus obtaining a chitosan solution.

[0012] Step 1.2: Add boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) to deionized water and sonicate for ten minutes using ultrasonic-assisted technology to completely disperse the solute and obtain a boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution.

[0013] Step 1.3: Add tannic acid to deionized water to obtain a tannic acid solution.

[0014] Step 1.4: Add sericin to deionized water to obtain a sericin solution.

[0015] In a preferred embodiment of the present invention, in step 1.1, the mass fraction of the acetic acid aqueous solution is 1-3%, and the concentration of the chitosan solution is 5-20 mg / mL; in step 1.2, the concentration of the boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution is 5-20 mg / mL; in step 1.3, the concentration of the tannic acid solution is 1-10 mg / mL; and in step 1.4, the concentration of the sericin solution is 1-10 mg / mL. Preferably, in step 1.1, the acetic acid aqueous solution has a mass fraction of 2% and the chitosan solution concentration is 20 mg / mL; in step 1.2, the boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution concentration is 20 mg / mL; in step 1.3, the tannic acid solution concentration is 5 mg / mL; and in step 1.4, the sericin solution concentration is 5 mg / mL.

[0016] In a preferred embodiment of the present invention, in step 2, the volume of boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution added is 1-5 mL, and the volume of tannic acid solution added is 1-5 mL. Preferably, the volume of boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution is 3 mL, and the volume of tannic acid solution is 1 mL.

[0017] In a preferred embodiment of the present invention, the method for adding the mixture and the sericin solution in step 3 is as follows: Step 3.1: Place the measured chitosan solution on a benchtop spin coater and use a 1 mL pipette to transfer the mixture.

[0018] Step 3.2: Turn on the desktop spin coater and use a pipette to drop the mixture drop by drop into the center of the chitosan solution.

[0019] Step 3.3: Use a pipette to transfer the sericin solution dropwise into the mixture formed by chitosan and the mixed solution.

[0020] In a preferred embodiment of the present invention, in step 3.1, the rotation speed of the tabletop spin coater is 50 r / min.

[0021] In a preferred embodiment of the present invention, in step 3.3, 10 drops (approximately 0.5 mL) of the sericin solution are added.

[0022] In a preferred embodiment of the present invention, in step 4, the method for preparing the "brick-mud" super-strong and super-tough biomimetic chitosan membrane involves placing the prepared solution in a natural wind to dry naturally, thereby obtaining the chitosan membrane.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention is made of all-natural ingredients, all raw materials are derived from renewable resources, the materials are completely biodegradable, the entire process requires no organic solvents, and it is environmentally friendly; 2. This invention has excellent mechanical properties. The biomimetic multi-level structural design significantly improves the strength and toughness of the material, increasing the strength by more than 60% compared to pure chitosan membranes, while also possessing good impact resistance. 3. This invention has good water resistance; the dynamic cross-linking network and interfacial toughening effect enable the material to maintain structural stability in water for a long time. 4. The process of this invention is simple and controllable. It adopts directional assembly and natural air drying process, which is simple to operate, mild conditions, and has the potential for large-scale production. Attached Figure Description

[0024] Figure 1 This is a front-side scanning electron microscope image of the biomimetic chitosan membrane prepared in Example 1 of the present invention, showing a "brick-and-mortar" layered structure. Figure 2 This is a reverse scanning electron microscope image of the biomimetic chitosan membrane prepared in Example 1 of the present invention. Figure 3 A cross-sectional scanning electron microscope image of the biomimetic chitosan membrane prepared in Example 1 of this invention. Figure 4 These are schematic diagrams of the biomimetic chitosan membranes obtained in different embodiments of the present invention. Figure 5 This is a flowchart illustrating the preparation method of the biomimetic chitosan membrane obtained in different embodiments of the present invention. Figure 6 This is a comparison chart of stress-strain curves of biomimetic chitosan membranes obtained in different embodiments of the present invention. Figure 7 X-ray diffraction patterns of biomimetic chitosan membranes obtained in different embodiments of the present invention. Figure 8 Infrared spectra of biomimetic chitosan membranes obtained in different embodiments of the present invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but the implementation of the present invention is not limited thereto. Example

[0026] This embodiment provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, which adopts a four-step method, including the following steps: (1) Preparation of solution Weigh 1 g of chitosan powder (CS), add 2% acetic acid aqueous solution, bring the volume to 50 mL, sonicate for 10 min, and let stand naturally to dissolve for one day to obtain a 20 mg / mL chitosan solution; weigh 1 g of boron nitride powder (BN), add deionized water, bring the volume to 50 mL, sonicate for 10 min to obtain a 20 mg / mL boron nitride solution; weigh 0.1 g of tannic acid and sericin powder respectively, add deionized water to bring the volume to 20 mL to obtain a 5 mg / mL tannic acid solution and a 5 mg / mL sericin solution respectively.

[0027] (2) Mixed reinforced phase Use a pipette to transfer 2 ml of 20 mg / mL boron nitride solution and 1 mL of 5 mg / mL tannic acid solution and mix thoroughly.

[0028] (3) Spin coating assembly Use a pipette to transfer 3 mL of 20 mg / mL chitosan solution into a container, fix the container on a benchtop spin coater, set the rotation speed to 50 r / min, and the time to 720 s. Start the spin coater, and use a pipette to drop the mixture obtained in step (2) dropwise into the center of the chitosan solution. Then, use a pipette to transfer 1 mL of 5 mg / mL sericin protein solution dropwise into the center of the rotating chitosan mixture.

[0029] (4) Drying The above system was dried under natural wind and then naturally demolded to obtain a chitosan film. Example

[0030] This embodiment provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, which adopts a four-step method, including the following steps: (1) Preparation of solution Weigh 1g of chitosan powder (CS), add 2% acetic acid aqueous solution, bring the volume to 50 mL, sonicate for 10 min, and let stand naturally to dissolve for one day to obtain a 20 mg / mL chitosan solution; weigh 1g of boron nitride powder (BN), add deionized water, bring the volume to 50 mL, sonicate for 10 min to obtain a 20 mg / mL boron nitride solution; weigh 0.1g of tannic acid and sericin powder respectively, add deionized water to bring the volume to 20 mL to obtain a 5 mg / mL tannic acid solution and a 5 mg / mL sericin solution respectively.

[0031] (2) Mixed reinforced phase Use a pipette to transfer 1 mL of 20 mg / mL boron nitride solution and 1 mL of 5 mg / mL tannic acid solution and mix them thoroughly.

[0032] (3) Spin coating assembly Use a pipette to transfer 3 mL of 20 mg / mL chitosan solution into a container, fix the container on a benchtop spin coater, set the rotation speed to 50 r / min, and the time to 720 s. Start the spin coater, and use a pipette to drop the mixture obtained in step (2) dropwise into the center of the chitosan solution. Then, use a pipette to transfer 1 mL of 5 mg / mL sericin protein solution dropwise into the center of the rotating chitosan mixture.

[0033] (4) Drying The above system was dried under natural wind and then naturally demolded to obtain a chitosan film. Example

[0034] This embodiment provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, which adopts a four-step method, including the following steps: (1) Preparation of solution Weigh 1g of chitosan powder (CS), add 2% acetic acid aqueous solution, bring the volume to 50 mL, sonicate for 10 min, and let stand naturally to dissolve for one day to obtain a 20 mg / mL chitosan solution; weigh 1g of boron nitride powder (BN), add deionized water, bring the volume to 50 mL, sonicate for 10 min to obtain a 20 mg / mL boron nitride solution; weigh 0.1g of tannic acid and sericin powder respectively, add deionized water to bring the volume to 20 mL to obtain a 5 mg / mL tannic acid solution and a 5 mg / mL sericin solution respectively.

[0035] (2) Mixed reinforced phase Use a pipette to transfer 2 mL of 20 mg / mL boron nitride solution as a mixture.

[0036] (3) Spin coating assembly Use a pipette to transfer 3 mL of 20 mg / mL chitosan solution into a container, fix the container on a benchtop spin coater, set the rotation speed to 50 r / min, and the time to 720 s. Start the spin coater, and use a pipette to drop the mixture obtained in step (2) dropwise into the center of the chitosan solution. Then, use a pipette to transfer 1 mL of 5 mg / mL sericin protein solution dropwise into the center of the rotating chitosan mixture.

[0037] (4) Drying The above system was dried under natural wind and then naturally demolded to obtain a chitosan film. Example

[0038] This embodiment provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, which adopts a four-step method, including the following steps: (1) Preparation of solution Weigh 1g of chitosan powder (CS), add 2% acetic acid aqueous solution, bring the volume to 50 mL, sonicate for 10 min, and let stand naturally to dissolve for one day to obtain a 20 mg / mL chitosan solution; weigh 1g of boron nitride powder (BN), add deionized water, bring the volume to 50 mL, sonicate for 10 min to obtain a 20 mg / mL boron nitride solution; weigh 0.1g of tannic acid and sericin powder respectively, add deionized water to bring the volume to 20 mL to obtain a 5 mg / mL tannic acid solution and a 5 mg / mL sericin solution respectively.

[0039] (2) Mixed reinforced phase Use a pipette to transfer 1 mL of 20 mg / mL boron nitride solution and 1 mL of 5 mg / mL tannic acid solution and mix them thoroughly.

[0040] (3) Spin coating assembly Use a pipette to transfer 3 mL of 20 mg / mL chitosan solution into a container, fix the container on a benchtop spin coater, set the speed to 50 r / min and the time to 720 s. Start the spin coater, and use a pipette to drop the mixture obtained in step (2) into the center of the chitosan solution one drop at a time, without adding any more sericin protein solution.

[0041] (4) Drying The above system was dried under natural wind and then naturally demolded to obtain a chitosan film.

[0042] Example

[0043] This embodiment provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, which adopts a four-step method, including the following steps: (1) Preparation of solution Weigh 1g of chitosan powder (CS), add 2% acetic acid aqueous solution, bring the volume to 50 mL, sonicate for 10 min, and let stand naturally to dissolve for one day to obtain a 20 mg / mL chitosan solution; weigh 0.5g of boron nitride powder (BN), add deionized water, bring the volume to 50 mL, sonicate for 10 min to obtain a 20 mg / mL boron nitride solution; weigh 0.1g of tannic acid and sericin powder respectively, add deionized water to bring the volume to 20 mL to obtain a 5 mg / mL tannic acid solution and a 5 mg / mL sericin solution respectively.

[0044] (2) Mixed reinforced phase Use a pipette to transfer 2 ml of 10 mg / mL boron nitride solution and 1 ml of 5 mg / mL tannic acid solution and mix them thoroughly.

[0045] (3) Spin coating assembly Use a pipette to transfer 3 mL of 20 mg / mL chitosan solution into a container, fix the container on a benchtop spin coater, set the speed to 50 r / min and the time to 720 s. Start the spin coater, and use a pipette to drop the mixture obtained in step (2) into the center of the chitosan solution one drop at a time, without adding any more sericin protein solution.

[0046] (4) Drying The above system was dried under natural wind and then naturally demolded to obtain a chitosan film.

[0047] Example

[0048] This embodiment provides a biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, which adopts a four-step method, including the following steps: (1) Preparation of solution Weigh 1g of chitosan powder (CS), add 2% acetic acid aqueous solution, bring the volume to 50 mL, sonicate for 10 min, and let stand naturally to dissolve for one day to obtain a 20 mg / mL chitosan solution; weigh 0.5g of iron oxide nanosheet powder (BN), add deionized water, bring the volume to 50 mL, sonicate for 10 min to obtain a 20 mg / mL iron oxide nanosheet solution; weigh 0.1g of tannic acid and sericin powder respectively, add deionized water to bring the volume to 20 mL to obtain a 5 mg / mL tannic acid solution and a 5 mg / mL sericin solution respectively.

[0049] (2) Mixed reinforced phase Use a pipette to transfer 2 ml of 10 mg / mL iron oxide nanosheet solution and 1 ml of 5 mg / mL tannic acid solution and mix them thoroughly.

[0050] (3) Spin coating assembly Use a pipette to transfer 3 mL of 20 mg / mL chitosan solution into a container, fix the container on a benchtop spin coater, set the speed to 50 r / min and the time to 720 s. Start the spin coater, and use a pipette to drop the mixture obtained in step (2) into the center of the chitosan solution one drop at a time, without adding any more sericin protein solution.

[0051] (4) Drying The above system was dried under natural wind and then naturally demolded to obtain a chitosan film.

Claims

1. A biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method, characterized in that, Includes the following steps: Step 1: Prepare chitosan solution, boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution, tannic acid solution, and sericin solution respectively. Step 2: Mix boron nitride (or iron oxide nanosheets, carbon nitride, graphene, etc.) solution with tannic acid solution to obtain a mixed solution. Step 3: Place the chitosan solution on a rotating carrier, drop the mixture obtained in step 2 into the chitosan solution, and then drop the sericin solution into it. Step 4: Air dry naturally to obtain the chitosan membrane.

2. The biomimetic "brick-and-mortar" structured ultra-strong and ultra-tough chitosan membrane and its preparation method as described in claim 1, characterized in that, The method for preparing the concentration solution of the raw material in step 1: Step 1.1: Add an aqueous acetic acid solution to the chitosan powder to dissolve it, thus obtaining a chitosan solution. Step 1.2: Add boron nitride to deionized water and disperse by ultrasonication to obtain a boron nitride solution. Step 1.3: Add tannic acid to deionized water to obtain a tannic acid solution. Step 1.4: Add sericin to deionized water to obtain a sericin solution.

3. The preparation method according to claim 2, characterized in that, The acetic acid aqueous solution in step 1.1 has a mass fraction of 1-3%, and the chitosan solution concentration is 5-20 mg / mL; the boron nitride solution concentration in step 1.2 is 5-20 mg / mL; the tannic acid solution concentration in step 1.3 is 1-10 mg / mL; and the sericin solution concentration in step 1.4 is 1-10 mg / mL.

4. The preparation method according to claim 1, characterized in that, In step 2, the volume of boron nitride solution added is 1-5 mL, and the volume of tannic acid solution added is 1-5 mL.

5. The preparation method according to claim 1, characterized in that, In step 3, the method for adding the mixture and sericin protein solution is as follows: Step 3.1: Place the chitosan solution on a benchtop spin coater at a speed of 50 r / min. Step 3.2: Drop the mixture into the center of the chitosan solution one drop at a time. Step 3.3: Add the sericin protein solution dropwise into the resulting mixed liquid.

6. The preparation method according to claim 5, characterized in that, In step 3.1, the volume of the sericin solution added is 0.5-1 ml.

7. The preparation method according to claim 1, characterized in that, In step 4, the preparation method for the "brick-mud" ultra-strong and ultra-tough biomimetic chitosan membrane involves an air-drying time of 12-24 hours.

8. Chitosan membrane obtained by any one of claims 1-8.

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