Unilaterally densified large-size biomimetic ceramic janus membrane and preparation method thereof

Abstract

The application belongs to the field of material chemistry, and particularly relates to a kind of one-side densification large-size biomimetic ceramic Janus film and a preparation method thereof.The Janus film is a two-layer structure composed of a dense layer and a loose layer, the dense layer is aragonite crystal, and the loose layer contains aragonite and calcite crystals.The application induces crystal densification growth by limited effect, does not need the extreme environment of high temperature and high pressure in traditional densification ceramic firing, successfully prepares one-side densification mineral film under mild experimental conditions, saves energy, and provides favorable conditions for subsequent mechanism research and expansion of synthesis method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biomineralization, and more particularly relates to a preparation method of a large-size Janus biomimetic ceramic film with unilateral densification. BACKGROUND

[0002] Calcium carbonate is one of the most common natural minerals, and widely exists in marine organisms. There are multiple types of calcium carbonate: 3 types of anhydrous crystal (CaCO3), with the stability from low to high being vaterite, aragonite and calcite; 2 types of hydrated crystal, with CaCO3·6H2O being metastable, and CaCO3·H2O being found in the dehydration process of CaCO3·6H2O, and CaCO3·H2O being less stable; 1 type of amorphous calcium carbonate (CaCO3·nH2O), which is unstable at normal temperature and pressure and is easy to be converted into a crystal state. Among them, the two types of crystals commonly found in organisms are aragonite and calcite, and amorphous calcium carbonate is often involved in the process of mineral transformation in life, such as the aragonite platelet in the “brick-mud structure” formed with chitin and polypeptide in shells, the aragonite prism on the back of snake tail, and the aragonite constituting a double-scale microcrystalline lattice structure in a multi-segmented starfish.

[0003] Biological organisms have long evolved to manufacture natural biominerals with densification through chemical modification, template effect, and especially limited effect, such as crinoids, and the performance of the densified minerals is much more excellent and diversified than that of geological minerals. The preparation of the densified minerals under mild conditions inspires scientists, so that the preparation of the densified ceramics is not necessarily limited to the extreme environment of high temperature and high pressure.

[0004] The limited effect refers to the growth of a crystal in a limited space rather than in a bulk solution, which exhibits different characteristics from the crystal grown in the bulk solution, such as crystal morphology, orientation, melting point, nucleation rate, crystal structure and crystal type, etc. Therefore, scientists can obtain ideal crystals for research by controlling the limited environment. Different limited environments include: the size of the limited space, from microns to nanometers; the shape of the limited space, including wedge-shaped, cylindrical pores, vesicles, primitive pools, porous media, etc.; the medium of the limited space, including carbon nanotubes, micelles, microfluidic chips, etc. In the limited space, the nucleation and growth mechanism of the crystal is quite different from that in the bulk solution, so it is often used to synthesize crystal types and morphologies that are not easy to obtain in the bulk solution. In order to better regulate the growth of the crystal, scientists use the limited space to explore the mechanism of the growth of the crystal, synthesize crystals with controllable properties and multiple functions, and constantly enrich the methods of constructing the limited space, such as synthesizing crystal hotels and porous materials.

[0005] There are numerous studies on the synthesis of crystals or the induction of dense structure by high temperature and high pressure, but there are few reports on the synthesis of dense crystals by confined effect under mild conditions. The Journal of Materials Chemistry B reported on the driving mechanism and mineralization morphology and characteristics of amorphous calcium carbonate infiltration in the confined space of collagen fibrils on page 880 of Volume 5 in 2016. The Journal of Colloid and Interface Science reported the conversion of amorphous calcium carbonate with high specific surface area into dense and pure vaterite induced by pressure on page 346 of Volume 611 in 2022. The Journal of Forests reported the induction of mineralization of lignin by high temperature and high pressure on page 1567 of Volume 14 in 2023.

[0006] Therefore, how to synthesize dense minerals in a confined space under mild conditions, and to elucidate the crystal growth mechanism in order to simplify the subsequent preparation steps, is still a major challenge in the field of biomaterials, which is of great significance and is one of the focuses of many forward-looking researchers in the field of ceramic preparation. SUMMARY

[0007] Therefore, the technical problem to be solved by the present application is to provide a single-sided dense large-size biomimetic ceramic Janus film and a preparation method thereof, in particular, a preparation method of a single-sided dense large-size biomimetic ceramic Janus film with adjustable dense degree. The present application can prepare a single-sided dense large-size calcium carbonate film under mild conditions without applying high temperature and high pressure, which is low in energy consumption and size-adjustable, and provides favorable conditions for further development of biomimetic dense ceramics and growth mechanism research.

[0008] To achieve the above purpose, the present application adopts the following technical solutions:

[0009] The present application provides a single-sided dense large-size biomimetic ceramic Janus film, which is a two-layer structure composed of a dense layer and a loose layer. The dense layer is aragonite crystal, and the loose layer contains aragonite and calcite crystals.

[0010] Further, the thickness of the single-sided dense large-size biomimetic ceramic Janus film is 1-3 μm.

[0011] Further, the aragonite crystals of the dense layer are composed of a plurality of large-size single crystals, and the loose layer has a particle accumulation morphology or a prismatic morphology.

[0012] Further, the dense layer and the loose layer of the present application are relative concepts. The dense layer refers to a morphology that is denser than the loose layer, so it is called a dense layer and the other layer is called a loose layer. The mechanical strength of the dense layer exceeds that of the loose layer.

[0013] Further, the crystal plane index of the dense layer includes (111) and (2-11), and the loose layer has (111) and (104) preferential orientation.

[0014] Further, the single-sided densification large-size biomimetic ceramic Janus film has a size of the organic-rich region in the dense layer within 1-100 nm.

[0015] Further, the single-sided densification large-size biomimetic ceramic Janus film is almost completely transparent.

[0016] The application further discloses a preparation method of the single-sided densification large-size biomimetic ceramic Janus film, which comprises the following steps:

[0017] A) modifying a substrate with a silicon-based reaction solution to obtain a hydrophilic substrate;

[0018] B) coating a chitosan solution on the surface of the hydrophilic substrate, drying the chitosan solution into a film and then performing acetylation treatment to obtain a chitin film, wherein the chitin film and the hydrophilic substrate form a confined space;

[0019] C) placing the hydrophilic substrate with the chitin film in a mineralization solution to perform mineralization, so as to obtain the single-sided densification large-size biomimetic ceramic Janus film, wherein the side close to the substrate is the dense layer of the Janus film, and the side far from the substrate is the loose layer of the Janus film.

[0020] Further, the substrate can be a glass substrate, and the modification of the substrate with the silicon-based reaction solution can make the substrate have hydrophilic groups, such as amino groups, carboxylate groups and hydroxyl groups.

[0021] Further, the area of the single-sided densification large-size biomimetic ceramic Janus film can be controlled by adjusting the area of the chitin film, and the thickness of the single-sided densification large-size biomimetic ceramic Janus film can be controlled by adjusting the mineralization time; the longer the mineralization time is, the thicker the thickness is.

[0022] Preferably, in step A), the silicon-based reaction solution is prepared by adding a silicon-based modifier, succinic anhydride and 4-dimethylaminopyridine into N,N-dimethylformamide, magnetically stirring at room temperature for 2 hours, and then mixing with ethanol.

[0023] Preferably, in step B), the mass concentration of the chitosan solution is 1.5-2%, and the coating volume of the chitosan solution on the surface of the hydrophilic substrate is 10-100 μL / cm.2 .

[0024] Preferably, in step B), the drying temperature is 0-37℃, and the drying time is 12-24 hours.

[0025] Preferably, in step B), the acetylation treatment is at a reaction temperature of 45℃, for not less than 4 hours, and the acetylation degree is not less than 100%.

[0026] Preferably, in step C), the cations in the mineralization solution include calcium ions and magnesium ions, the anions include bicarbonate ions and chloride ions, and the polymer is polyacrylic acid. The Ca 2+ concentration is 7.9-9.8 mmol / L, the Mg 2+ concentration is 25.8 mmol / L, the HCO3 - concentration is 15.7-19.6 mmol / L, the Cl - concentration is 51.7 mmol / L, and the polyacrylic acid concentration is 0.02 mmol / L. The molecular weight of the polyacrylic acid is 1800 g / mol.

[0027] Preferably, in step C), the container used for mineralization is sealed with a plastic film and is provided with multiple holes.

[0028] Preferably, in step C), the mineralization temperature is 37-40℃, and the mineralization time is 3-7 days.

[0029] Preferably, in step C), after the mineralization is completed, the product is cleaned with ethanol and is naturally dried.

[0030] The present application provides a single-sided densification large-size biomimetic ceramic Janus film, which has a layered and single-sided densification microstructure. Compared with the prior art, the beneficial effects of the present application are reflected in:

[0031] 1. The present application uses 3-aminopropyl triethoxysilane and the like as a modifying agent to perform hydrophilic treatment on ordinary glass and the like substrates. The obtained hydrophilic glass is closely attached to the coated organic film, can successfully construct a limited space with appropriate size before mineralization, thereby regulating the mineralization process, and obtains a single-sided densification large-size biomimetic ceramic Janus film, which provides favorable conditions for subsequent construction of high-strength densification artificial large-size mineral film.

[0032] 2、The present application successfully obtains a limited space through chemical modification, and crystals nucleate and grow in the limited space, so that a large-size biomimetic ceramic Janus film with one side densified is obtained under mild mineralization conditions, and the side close to the chemical modification surface is a single crystal aragonite, and scanning electron microscopy shows that the density is high, The present application induces the dense growth of crystals by the limited effect, and does not need the extreme environment of high temperature and high pressure for traditional densification ceramics, and successfully prepares a mineral film with one side densified under mild experimental conditions, saves energy, and provides favorable conditions for subsequent mechanism research and expansion of synthesis method. In addition, the limited effect plays an important role in the present application, which can also bring the possibility of explaining the regulation mechanism of the limited effect in the synthesis of the dense crystal of the marine organism. Meanwhile, the preparation method provided by the present application is simple, the conditions are mild, the controllability is strong, the expansibility is strong, and is suitable for subsequent research application and expansion. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Raman spectrum of the chemical modification surface prepared in example 1 of the present application;

[0034] Figure 2 Scanning electron microscope (SEM) image of the chitin film prepared in example 1 of the present application;

[0035] Figure 3 X-ray diffraction pattern of the mineral film prepared in example 1 of the present application;

[0036] Figure 4 Scanning electron microscope (SEM) image of the mineral film prepared in example 1 of the present application;

[0037] Figure 5 Scanning electron microscope (SEM) image of another mineral film prepared in example 1 of the present application;

[0038] Figure 6 High-resolution transmission electron microscope (HRTEM) image of the mineral film prepared in example 1 of the present application;

[0039] Figure 7 Fig. a and Fig. b in the figure are high-resolution transmission electron microscope (HRTEM) images of the dense layer and the loose layer of the mineral film prepared in example 1 of the present application, respectively;

[0040] Figure 8 Selected area electron diffraction (SAED) pattern of the dense layer of the mineral film prepared in example 1 of the present application;

[0041] Figure 9 Selected area electron diffraction (SAED) pattern of the loose layer of the mineral film prepared in example 1 of the present application;

[0042] Figure 10The mechanical property (Nano-indentation) profile of the mineral thin film prepared for Example 1 of the present application. DETAILED DESCRIPTION

[0043] For further understanding of the present application, the embodiments of the present application are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present application, and are not limitations on the claims of the present application.

[0044] All raw materials of the present application are not particularly limited in source, and can be purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0045] All raw materials of the present application are not particularly limited in purity, and the present application preferably uses analytical pure or conventional purity in the field of biomimetic technology.

[0046] All raw materials of the present application are of conventional grade and abbreviation, and each grade and abbreviation is clear and explicit in the field of its relevant use. Those skilled in the art can purchase or prepare them by conventional methods according to the grade, abbreviation and corresponding use.

[0047] All processes of the present application are of conventional abbreviation, and each abbreviation is clear and explicit in the field of its relevant use. Those skilled in the art can understand the conventional process steps according to the abbreviation.

[0048] The present application provides a single-sided densification large-size biomimetic ceramic Janus thin film, which has a layered micro-morphology.

[0049] The present application is not particularly limited in the configuration of the layered, dense layer and loose layer micro-morphology of the thin film, and can be of conventional layered, dense layer and loose layer configuration structure well known to those skilled in the art. Those skilled in the art can select and adjust it according to the actual application, product requirements and specific application, and it can be normally understood by those skilled in the art.

[0050] The present application is not particularly limited in principle to the specific size of the single-sided densification large-size biomimetic ceramic Janus thin film, and those skilled in the art can select and adjust it according to the actual situation, product requirements and specific application. In order to ensure the structural characteristics of the single-sided densification large-size biomimetic ceramic Janus thin film, improve the research efficiency and increase the thickness of the dense layer, the mineralization time is preferably 3 days.

[0051] The appearance of the large-size biomimetic ceramic Janus film with one-side densification is not particularly limited in principle, and those skilled in the art can select and adjust according to the actual application, product requirements and specific application. In order to ensure the structural characteristics of the biomimetic densification ceramic, the mechanical strength of the film obtained within the mineralization time is increased, and the thickness of the dense layer is preferably 1-3 μm.

[0052] The molar concentration of magnesium element in the large-size biomimetic ceramic Janus film with one-side densification is not particularly limited in principle, and those skilled in the art can select and adjust according to the actual application, product requirements and specific application. In order to ensure the structural characteristics of the biomimetic densification ceramic, the thickness of the dense layer of the film obtained within the mineralization time is increased, and the molar concentration of magnesium element is preferably 25.8 mmol / L, and the molar concentration of polyacrylic acid is preferably 0.02 mmol / L.

[0053] In order to further illustrate the present application, the preparation method of the biomimetic densification ceramic provided by the present application is described in detail below in combination with examples.

[0054] The reagents used in the following examples are commercially available.

[0055] Example 1

[0056] (1) Preparation of silicon-based reaction solution

[0057] 2.21 g of 3-aminopropyltriethoxysilane, 1.5 g of succinic anhydride and 0.218 g of 4-dimethylaminopyridine were added to 10 mL of N,N-dimethylformamide, and magnetically stirred at room temperature for 2 hours, mixed with 80 mL of ethanol to obtain a silicon-based reaction solution.

[0058] (2) Modification of glass

[0059] The silicon-based reaction solution obtained in step (1) was added to the cleaned and dried glass, and incubated at 60°C for 2 hours. The size of the glass was 2 cm*1 cm*1 mm. Then it was washed with deionized water and dried to obtain a chemically modified surface.

[0060] Figure 1 The Raman spectrum of the chemically modified surface prepared in this example is shown in the figure. From the figure, it can be seen that the δ -1 bending vibration at 596 cm C-C＝O , and the ν -1 and ν N-H stretching vibration at 3365 cm O-H .

[0061] (3) Preparation of chitin film

[0062] Chitosan was added to 98 g of deionized water, 2 mL of glacial acetic acid was added, and the solution was stirred at room temperature until it became clear, obtaining a chitosan solution with a mass fraction of about 2%. 80 μL of the chitosan solution was coated on the modified glass obtained in step (2), and the glass was dried overnight at room temperature. Finally, the dried chitosan film was placed in a mixture of 90 mL of methanol and 10 mL of acetic anhydride at 45°C for 4 hours, and then washed with deionized water and dried, obtaining a chitin film, which formed a confined space with the glass.

[0063] Figure 2 The scanning electron microscope (SEM) image of the chitin film prepared in this example can be seen in FIG. 1, and the chitin fibers can be seen, and the thickness of the chitin film is about 3 μm.

[0064] (4) Preparation of mineralization solution

[0065] Excess calcium carbonate was dissolved in 500 mL of deionized water, and CO2 gas was continuously introduced into the solution, which was stirred magnetically in a water bath at 25°C for 1 hour, obtaining a calcium carbonate solution. 40.66 g of magnesium chloride hexahydrate was dissolved in 100 mL of deionized water, obtaining a magnesium chloride solution. 1.44 g of polyacrylic acid (molecular weight 1800 g / mol) was dissolved in 100 mL of deionized water, obtaining a polyacrylic acid solution. 50 mL of the calcium carbonate solution was poured into a 100 mL beaker, and 800 μL of the magnesium chloride solution and 125 μL of the polyacrylic acid solution were added, obtaining a mineralization solution.

[0066] (5) Mineralization

[0067] The chitin film glass obtained in step (3) was placed in the mineralization solution, the beaker opening was covered with a plastic film, four holes were made with a needle, and the beaker was incubated at 40°C for 3 days. After the incubation, the beaker was washed with ethanol and dried at room temperature, obtaining a large-size Janus film with a dense layer on one side.

[0068] Figure 3 The X-ray diffraction pattern of the mineral film prepared in this example can be seen in FIG. 3, and it can be seen that the Janus film contains aragonite and calcite.

[0069] Figure 4 The scanning electron microscope (SEM) image of the mineral film prepared in this example can be seen in FIG. 4, and it can be seen that the smooth dense layer and the loose layer have a prismatic morphology.

[0070] Under the conditions of this example, a mineral film can also be obtained in which the loose layer has another morphology, and the scanning electron microscope (SEM) image thereof is shown in FIG. 5, and it can be seen that the smooth dense layer and the loose layer have a granular morphology. Figure 5

[0071] Figure 6 ​The high resolution transmission electron microscope (HRTEM) image of the mineral film prepared in the embodiment shows obvious boundary between the dense layer and the loose layer.

[0072] Figure 7 Fig. a is the high resolution transmission electron microscope (HRTEM) image of the dense layer of the mineral film prepared in the embodiment, which shows the 1-100 nm organic precipitation area (white arrow) in the dense layer; Figure 7 Fig. b is the high resolution transmission electron microscope (HRTEM) image of the loose layer of the mineral film prepared in the embodiment, which shows the accumulation of particles.

[0073] Figure 8 Fig. c is the selected area electron diffraction (SAED) spectrum of the dense layer of the mineral film prepared in the embodiment, which shows that the dense layer is aragonite single crystal.

[0074] Figure 9 Fig. d is the selected area electron diffraction (SAED) spectrum of the loose layer of the mineral film prepared in the embodiment, which shows that the loose layer is composed of aragonite and calcite and has preferential orientation (111) and (104).

[0075] Figure 10 Fig. e is the modulus spectrum of the mineral film prepared in the embodiment, which shows that the hardness of the dense layer is higher than that of the loose layer.

[0076] The above merely shows the exemplary embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A large scale biomimetic ceramic Janus film unilaterally densified, characterized by: The Janus film is a two-layer structure composed of a dense layer and a loose layer, the dense layer is aragonite crystal, and the loose layer contains aragonite and calcite crystals; the preparation method of the single-sided densification large-size biomimetic ceramic Janus film comprises the following steps: A) modifying a glass substrate with a silicon-based reaction solution to obtain a hydrophilic substrate; B) coating a chitosan solution on the surface of the hydrophilic substrate, drying the film and then performing acetylation treatment to obtain a chitin film, wherein the chitin film and the hydrophilic substrate form a confined space; C) placing the hydrophilic substrate with the chitin film in a mineralization solution for mineralization to obtain a single-sided densification large-size biomimetic ceramic Janus film.

2. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: The aragonite crystals of the dense layer are composed of multiple large-size single crystals.

3. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: The loose layer has a particle accumulation morphology or a prismatic morphology.

4. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: The strength of the dense layer exceeds that of the loose layer.

5. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: The crystal plane indices of the dense layer include (111) and (2-11), and the loose layer has (111) and (104) orientations.

6. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: The area of the single-sided densification large-size biomimetic ceramic Janus film can be controlled by adjusting the area of the chitin film, and the thickness of the single-sided densification large-size biomimetic ceramic Janus film can be controlled by adjusting the mineralization time.

7. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: The silicon-based modifier in the silicon-based reaction solution is one of octadecylsilatrithiolsilane, 3-aminopropyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane, 3-[(2,3)-epoxypropoxy]propyl methyl dimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

8. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: Ca 2+ concentration of 7.9-9.8 mmol / L, Mg 2+ concentration of 25.8 mmol / L, HCO3 - concentration of 15.7-19.6 mmol / L, Cl - concentration of 51.7 mmol / L, and polyacrylic acid concentration of 0.02 mmol / L.

9. The unilaterally densified large size biomimetic ceramic Janus membrane of claim 1, wherein: In step C), the temperature of the mineralization is 37-40℃, and the time of the mineralization is 3-7 days.

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