A hydrogel coating constructed on a titanium alloy surface and its preparation method

Abstract

This invention belongs to the field of intelligent hydrogel preparation technology, and relates to a hydrogel coating constructed on the surface of titanium alloy and its preparation method. The method for constructing a hydrogel coating on the surface of titanium alloy includes the following steps: (1) preparing hydroxyapatite-coated MXene; (2) adding polyvinyl alcohol and polyacrylic acid to the hydroxyapatite-coated MXene to prepare a sol; (3) spin-coating the sol obtained in step (2) onto the surface of titanium alloy, and performing cyclic freeze-thaw operations, thereby constructing a hydrogel coating on the surface of titanium alloy. Compared with the prior art, this invention improves the tribological properties of the hydrogel coating on the surface of titanium alloy by adding MXene, and the overall process is simple and the effect is outstanding.

Description

Technical Field

[0001] This invention belongs to the field of intelligent hydrogel preparation technology, and relates to a hydrogel coating constructed on the surface of a titanium alloy and its preparation method. Background Technology

[0002] Ti-6Al-4V alloy is currently the most widely used bone implant material, but its poor surface wear resistance and bioinertness have been significant causes of implant failure in vivo. Surface modification of titanium alloys is a feasible solution to extend their lifespan. However, simultaneously improving the biotribological properties and bioactivity of titanium alloy surfaces through modification still faces certain challenges at both the fundamental scientific and technological levels. Therefore, research on titanium alloy surface treatment processes and the evaluation and mechanistic analysis of modified surface properties has significant theoretical and practical value. Surface coating technology is a crucial processing method in the field of titanium alloy surface treatment. Depending on the required performance, coatings meeting different needs can be prepared on the titanium alloy surface. There are many methods for constructing surface coatings, commonly including electrochemical deposition, chemical assembly, and sol-gel methods.

[0003] For example, Chinese patent document CN 104857574 B, published on August 11, 2017, entitled "Intelligent Nanohydrogel Topological Structure Antibacterial Bone Plate and its Manufacturing Method," discloses an intelligent nanohydrogel topological structure antibacterial bone plate. The substrate surface is covered with a core of polyethylene glycol-co-acrylic acid microgel and an outer controlled-release shell of pH-sensitive polymethacrylic acid microgel. These two layers constitute intelligent charge gradient radially distributed composite microparticles. This composite microparticle coating forms a topological antibacterial structure on the surface of stainless steel, titanium, or titanium alloy bone plates and loads β-defensin-1-3, lactoferrin 1-11, LL-37, histone-rich analogues, endogenous antimicrobial peptide-1, and artificially synthesized cationic antimicrobial peptides. However, this patent only verifies the bactericidal effect of the hydrogel. It should be noted that this patent document does not disclose the influence of the hydrogel coating on its frictional properties.

[0004] For example, Chinese patent document CN 111363167 A, published on July 3, 2020, entitled "A Preparation Method and Product of RGO / HA / PVA Shape Memory Hydrogel," discloses a preparation method and product of RGO / HA / PVA shape memory hydrogel. The method involves incorporating a composite powder of HA and RGO into a PVA matrix via in-situ growth, successfully preparing a structurally uniform RGO / HA / PVA hydrogel. The RGO / HA / PVA hydrogel exhibits a uniform structure, with HA particles evenly dispersed within the PVA matrix, and demonstrates good thermal stability. Compared to pure PVA, the tensile strength of the RGO / HA / PVA hydrogel is increased by 3 times, and the elongation at break is increased by approximately 7 times. The RGO / HA / PVA hydrogel also exhibits good shape memory properties under thermally induced stimulation conditions in solvents (water and PBS solution). This patent document suggests that this type of hydrogel possesses good viscoelasticity. However, it should be noted that the PVA hydrogel disclosed in the patent document has defects such as poor mechanical properties and insufficient bonding strength with hard matrix materials, and cannot achieve the effect of improving the friction coefficient between iron alloy and cortical bone.

[0005] Based on the development of existing technologies, it can be seen that there is a lack of an effective method to significantly improve the tribological properties of hydrogel coatings on titanium alloy surfaces. Summary of the Invention

[0006] Given the lack of effective solutions in the existing technology to significantly improve the tribological properties of hydrogel coatings on titanium alloy surfaces, this invention provides a hydrogel coating constructed on titanium alloy surfaces and its preparation method.

[0007] The present invention improves the tribological properties of the hydrogel coating on the surface of titanium alloy by adding HA-MXene. The overall process is simple and the effect is outstanding.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] This invention first provides a method for constructing a hydrogel coating on a titanium alloy surface, comprising the following steps:

[0010] (1) Preparation of hydroxyapatite-coated MXene;

[0011] (2) A sol was prepared by adding polyvinyl alcohol and polyacrylic acid to MXene coated with hydroxyapatite;

[0012] (3) Spin-coat the sol obtained in step (2) onto the surface of the titanium alloy and perform a cyclic freeze-thaw operation to construct a hydrogel coating on the surface of the titanium alloy.

[0013] In one embodiment of the present invention, the method for preparing hydroxyapatite-coated MXene in step (1) is as follows:

[0014] (1.1) MXene solution was prepared by exfoliation of the ternary precursor Ti3AlC2;

[0015] (1.2) Ca(NO3)2·4H2O and (NH4)2HPO4 aqueous solution were added dropwise to MXene solution. The mixture was heated to react. After the reaction, the mixture was cooled to room temperature, precipitated and aged overnight. Then, the black brown precipitate was centrifuged and washed several times with deionized water to prepare hydroxyapatite-coated MXene, abbreviated as HA-MXene.

[0016] In one embodiment of the present invention, in step (1.1), the method for obtaining MXene solution by peeling off the ternary precursor Ti3AlC2 is as follows: hydrogen fluoride solution is slowly introduced into the ternary precursor Ti3AlC2 to obtain MXene solution.

[0017] In one embodiment of the present invention, the hydrogen fluoride solution is a 40% hydrogen fluoride solution by mass.

[0018] In one embodiment of the present invention, in step (1.2), the amounts of Ca(NO3)2·4H2O, (NH4)2HPO4 aqueous solution and MXene solution are related as follows: 2g-10g of Ca(NO3)2·4H2O and 1g-6g of (NH4)2HPO4 aqueous solution are added dropwise to a solution containing 0.1g-1g of MXene.

[0019] In one embodiment of the present invention, in step (1.2), after adding the aqueous solutions of Ca(NO3)2·4H2O and (NH4)2HPO4 to the MXene solution, NH3·H2O is also added to adjust the pH of the mixed solution to 10.

[0020] In one embodiment of the present invention, in step (1.2), the heating reaction conditions are: the mixture is heated to 90°C and reacted for 2 hours.

[0021] In one embodiment of the present invention, in step (2), the preparation process of the sol is specifically as follows: polyvinyl alcohol, polyacrylic acid and polydopamine are added to the suspension of HA-MXene, reacted, and cooled to obtain the sol.

[0022] In one embodiment of the present invention, in step (2), the amounts of polyvinyl alcohol, polyacrylic acid, polydopamine and HA-MXene are: 1g-2g PVA and 0.2g-1g PAA, 0.05g-0.1g PDA and 0-0.01g HA-MXene.

[0023] In one embodiment of the present invention, in step (2), the reaction conditions are: reacting at 90°C for 3 hours.

[0024] In one embodiment of the present invention, the method for performing the cyclic freezing and thawing operation in step (3) is as follows: freezing at -10°C for 24 hours, thawing at room temperature for 12 hours, and repeating the cyclic freezing and thawing operation 3 times.

[0025] In one embodiment of the present invention, after step (3) constructs a hydrogel coating on the titanium alloy surface, the tribological properties of the hydrogel coating constructed on the titanium alloy surface are verified by the following method:

[0026] By controlling the amount of HA-MXene added, the friction coefficient of the prepared hydrogel coating was measured after rubbing it under the same time, frequency and load.

[0027] When performing tribological performance verification, the MXene content was controlled at 0, 0.01 wt.%, 0.05 wt.%, and 0.1 wt.%, respectively.

[0028] When verifying the tribological properties, the specific friction process is as follows: 1 N, reaction time 20 min, 1 Hz.

[0029] The present invention further provides a hydrogel coating constructed on the surface of a titanium alloy based on the above preparation method.

[0030] The present invention further provides a titanium alloy having the above-mentioned hydrogel coating on its surface.

[0031] In the technical solution of this invention, the tribological properties of the hydrogel coating on the titanium alloy surface are improved by adding HA-MXene. The overall process is simple and the effect is outstanding. The hydrogel obtained by the method of this invention can effectively improve the tribological properties of the hydrogel coating on the titanium alloy surface.

[0032] This application enhances the tribological properties of hydrogel coatings on titanium alloy surfaces by adding HA-MXene, which is an innovative means of improving the tribological properties of hydrogel coatings on titanium alloy surfaces and a technical solution that was previously impossible for those skilled in the art to achieve.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. This invention innovatively incorporates HA-MXene to prepare a hydrogel coating on the surface of titanium alloys. This method is simple, feasible, environmentally friendly, and non-toxic.

[0035] 2. Compared with existing technologies, the tribological properties of the hydrogel coating on the titanium alloy surface prepared by this method are greatly improved. Attached Figure Description

[0036] Figure 1 The infrared spectrum of MXene in Example 1;

[0037] Figure 2 The friction coefficient diagram shows the friction coefficient of the hydrogel coatings on the titanium alloy surfaces prepared in Examples 1, 2, 3, and 4. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0039] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0040] Example 1

[0041] In this embodiment, polyvinyl alcohol, polyacrylic acid, and polydopamine are added to a suspension of HA-MXene to prepare a hydrogel coating on the surface of a titanium alloy to improve its tribological properties. The preparation method includes the following steps:

[0042] (1) First, hydrogen fluoride solution (100 ml, 40 wt%) was slowly introduced into 1 g of ternary precursor Ti3AlC2.

[0043] (2) Then disperse it in 100 ml of deionized water and filter the mixture using a hydrophilic 200 nm polytetrafluoroethylene porous membrane. Wash it thoroughly with deionized water, ethanol and deionized water in sequence.

[0044] (3) The mixture was then dried overnight in a vacuum oven at 65°C using the LPE method. This further transformed the bulk Ti3C2 into two-dimensional Ti3C2-based MXene nanosheets.

[0045] (4) The dry, blocky Ti3C2 powder was then simply mixed.

[0046] (5) The bulk Ti3C2 / NMP mixture was then sonicated at 10°C with 10 mg / mL of n-methylpyrrolidone (NMP). The ultrasonic power was 400 W and the sonication time was 48 h.

[0047] (6) Centrifuge at a lower speed of 8000 RPM for 30 min to obtain a 2D Ti3C2-based MXene / NMP mixture, and then centrifuge at a higher speed of 18000 RPM for 30 min to obtain 2D Ti3C2-based MXene nanosheets in NMP solvent.

[0048] (8) Two-dimensional Ti3C2-based MXene nanosheets were obtained and freeze-dried at -60℃ for 48 hours.

[0049] (9) Add 4g of Ca(NO3)2·4H2O and 1.3g of (NH4)2HPO4 aqueous solution dropwise to a solution containing 0.1g of MXene (adjust the pH to 10 by adding 25% NH3·H2O). The mixture is heated to 90°C and reacted for 2 hours.

[0050] (10) After the reaction, the mixture was cooled to room temperature, precipitated, and aged overnight. Then, the dark brown precipitate was centrifuged and washed several times with deionized water to prepare HA-MXene.

[0051] (11) Add polyvinyl alcohol (0.8g), polyacrylic acid (0.2g) and polydopamine (0.05g) into a 50ml three-necked flask and react at 90℃ for 3 hours.

[0052] (12) After cooling, a sol is obtained.

[0053] (13) After spin coating the sol onto the surface of the titanium alloy, freeze it at -10℃ for 24 hours and thaw it at room temperature for 12 hours. Repeat the freezing and thawing cycle 3 times.

[0054] (14) The prepared titanium alloy surface hydrogel coating was tested under a high frequency reciprocating friction and wear tester. The experimental conditions were: 1N, 1Hz, 20min, and the friction coefficient was obtained.

[0055] from Figure 1 From this, we can clearly draw the following conclusion: 3460cm -1 There is a very strong -OH stretching vibration peak at 605 cm⁻¹. -1 and 567cm -1 The characteristic peak at that location is PO4. 3- Characteristic peaks of CO3 2- The characteristic peak appears at 1400 cm⁻¹ -1 and 1640cm -1 Location. 1400cm -1 The presence of the splitting peak indicates the presence of CO3 in hydroxyapatite. 2- This is an important indicator, proving that hydroxyapatite modification was performed on the MXene surface.

[0056] Example 2

[0057] This embodiment provides a study on the preparation of a hydrogel coating on a titanium alloy surface. The specific steps are basically the same as in Example 1, except that in step (11), in this embodiment, polyvinyl alcohol (0.8g), polyacrylic acid (0.2g), and polydopamine (0.05g) are added to a suspension containing 0.0005g HA-MXene, and then added to a 50ml three-necked flask and reacted at 90°C for 3 hours.

[0058] Example 3:

[0059] This embodiment provides a study on the preparation of a hydrogel coating on a titanium alloy surface. The specific steps are basically the same as in Example 1, except that in step (11), in this embodiment, polyvinyl alcohol (0.8g), polyacrylic acid (0.2g), and polydopamine (0.05g) are added to a suspension containing 0.0025g HA-MXene, and then added to a 50ml three-necked flask and reacted at 90°C for 3 hours.

[0060] Example 4:

[0061] Compared with Example 1, most of them are the same, except that in step (11), in this example, polyvinyl alcohol (0.8g), polyacrylic acid (0.2g) and polydopamine (0.05g) are added to a suspension containing 0.005g HA-MXene, and then added to a 50ml three-necked flask and reacted at 90°C for 3 hours.

[0062] The method for detecting the friction coefficient of the hydrogel coating on the titanium alloy surface is as follows: the sample plate is placed in the sample cell of UMT, and bovine serum albumin (SBF) is used as the liquid environment. The experimental conditions are: load 1N, frequency 1Hz, stroke 2mm, and time 30min.

[0063] The friction coefficient diagrams of the hydrogel coatings prepared on the titanium alloy surfaces in Examples 1, 2, 3, and 4 are shown below. Figure 2 As shown, Figure 2 The sample with 0 g of HA-MXene was named PPPHM-0, the sample with 0.0005 g of HA-MXene was named PPPHM-1, the sample with 0.0025 g of HA-MXene was named PPPHM-2, and the sample with 0.005 g of HA-MXene was named PPPHM-3. From... Figure 2The results showed that under SBF lubrication conditions, the COF of the hydrogel-coated samples on the titanium alloy surface underwent a break-in period before gradually stabilizing. The average friction coefficient of the hydrogel-coated surface was significantly lower than that of the Ti group, indicating that the hydrogel coating greatly reduced the friction coefficient of the titanium alloy surface. Furthermore, the comparison of friction coefficients among the hydrogel-coated samples showed that with the addition of HA-MXene, the COF of the samples decreased with increasing dosage. PPPHM-3 had the lowest ACOF (0.102), which was 86.9% lower than that of the Ti group (0.783), exhibiting better anti-wear properties.

[0064] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for constructing a hydrogel coating on a titanium alloy surface, characterized in that, Includes the following steps: (1) Preparation of hydroxyapatite-coated MXene; (2) Polyvinyl alcohol, polyacrylic acid and polydopamine were added to a suspension of MXene coated with hydroxyapatite, reacted and cooled to obtain a sol. (3) Spin-coat the sol obtained in step (2) onto the surface of the titanium alloy and perform a cyclic freeze-thaw operation to construct a hydrogel coating on the surface of the titanium alloy. In step (1), the preparation method of hydroxyapatite-coated MXene is as follows: (1.1) MXene solution was prepared by exfoliation of the ternary precursor Ti3AlC2; (1.2) Ca(NO3)2⋅4H2O and (NH4)2HPO4 aqueous solution were added dropwise to MXene solution. The mixture was heated to react. After the reaction, the mixture was cooled to room temperature, precipitated and aged overnight. Then, the black brown precipitate was centrifuged and washed several times with deionized water to prepare hydroxyapatite-coated MXene, i.e., HA-MXene.

2. The method for constructing a hydrogel coating on a titanium alloy surface according to claim 1, characterized in that, In step (1.1), the method for obtaining MXene solution by peeling off the ternary precursor Ti3AlC2 is as follows: hydrogen fluoride solution is slowly introduced into the ternary precursor Ti3AlC2 to obtain MXene solution.

3. The method for constructing a hydrogel coating on a titanium alloy surface according to claim 1, characterized in that, In step (1.2), the amounts of Ca(NO3)2⋅4H2O, (NH4)2HPO4 aqueous solution, and MXene solution are related as follows: 2g-10g Ca(NO3)2⋅4H2O and 1g-6g (NH4)2HPO4 aqueous solution are added dropwise to 0.1g-1g MXene solution.

4. The method for constructing a hydrogel coating on a titanium alloy surface according to claim 1, characterized in that, In step (1.2), after adding Ca(NO3)2⋅4H2O and (NH4)2HPO4 aqueous solution to the MXene solution, NH3⋅H2O is added to adjust the pH of the mixed solution to 10. In step (1.2), the heating reaction conditions are: the mixture is heated to 90°C and reacted for 2 hours.

5. The method for constructing a hydrogel coating on a titanium alloy surface according to claim 1, characterized in that, In step (2), the dosage relationship of polyvinyl alcohol, polyacrylic acid, polydopamine and HA-MXene is: 1g-2g PVA and 0.2g-1g PAA, 0.05g-0.1g PDA and 0-0.01g HA-MXene; In step (2), the reaction conditions are: react at 90°C for 3 hours.

6. The method for constructing a hydrogel coating on a titanium alloy surface according to claim 1, characterized in that, In step (3), the method for performing the cyclic freezing and thawing operation is as follows: freeze at -10℃ for 24 hours, thaw at room temperature for 12 hours, and repeat the cyclic freezing and thawing operation 3 times.

7. A hydrogel coating constructed on a titanium alloy surface based on the method of any one of claims 1-6.

8. A titanium alloy having a surface containing the hydrogel coating of claim 7.

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