Preparation method and application of chitosan / MXene aerogel for ink direct writing 3D printing

Abstract

The invention belongs to the technical field of aerogel heat insulation, shielding and energy collection, and discloses a method for preparing chitosan / MXene aerogel through direct ink writing (DIW) 3D printing, and the distance between MXene nanosheets is increased due to the interaction between chitosan and MXene molecules. The electrical conductivity, the dielectric property and the electromagnetic interference (EMI) shielding effect are improved due to the high MXene content, and the EMI shielding effect of 27 dB is achieved through 10 wt% of MXene aerogel. The thermal conductivity initially decreases, but later increases as the concentration of MXene increases. The more the MXene is, the higher the Young modulus and the tensile strength are, but the elongation at break is reduced. The printed aerogel is used for a friction nano generator (TENG), the output voltage is increased from 22V of pure chitosan aerogel to 110V of 2wt% MXene, and the current is slightly increased. The invention innovatively provides the application of the DIW 3D printing chitosan / MXene aerogel in the fields of energy collection, EMI shielding and heat insulation.

Description

Technical Field

[0001] The present invention belongs to the field of chitosan / MXene aerogel thermal insulation, shielding, and energy collection, and in particular relates to a preparation method and application of ink direct writing 3D printing chitosan / MXene aerogel. Background Art

[0002] In modern times, with the widespread adoption of electronic devices, advancements in communication technologies such as 5G, and the increasing use of sensitive electronic systems in healthcare, aerospace, and automotive industries, effective EMI shielding is essential to prevent performance degradation, ensure reliable operation of critical systems, comply with regulatory standards, and protect human health from potential electromagnetic hazards. Therefore, there is an urgent need to develop efficient, lightweight, and durable EMI shielding materials to reduce the risks associated with electromagnetic interference.

[0003] Triboelectric nanogenerators (TENGs) integrated into aerogels represent a cutting-edge approach for mechanical energy harvesting. Aerogels' high porosity, flexibility, and large surface area significantly enhance contact charging, a key mechanism in TENGs. Their tunable properties, combined with the incorporation of conductive materials such as MXenes, amplify the triboelectric effect, thereby improving energy conversion efficiency. This makes aerogel-based TENGs ideal for developing lightweight, flexible, and wearable devices capable of converting mechanical energy generated by motion or vibration into electrical energy for practical applications. 3D printing of aerogels for TENGs utilizes techniques such as direct ink writing (DIW) or stereolithography to create highly porous, customized structures. The printing ink is formulated from a precursor gel infused with functional nanomaterials or graphene, enhancing triboelectric properties. After printing, the aerogel undergoes a drying process such as freeze-drying or supercritical drying to maintain its porous network. This approach allows for precise control over the aerogel's structural design, maximizing mechanical flexibility and triboelectric efficiency for advanced energy harvesting applications.

[0004] The application of 3D printed chitosan / MXene aerogel in TENG system and EMI shielding. Through the above analysis, the problems and defects of the existing technology are: it cannot achieve the complexity of electrolyte structure and the flexibility of size.

[0005] 3D-printed chitosan / MXene aerogels possess ultralight porous structures and remarkable multifunctional properties. Their exceptional performance in EMI shielding, thermal insulation, and energy harvesting is intrinsically linked to their highly porous microstructure and significant specific surface area. This unique combination of low density and exceptional functionality makes these aerogels highly advantageous in applications where material efficiency and multifunctionality are crucial. These unique properties make aerogels promising candidates for advanced applications in diverse fields, including architecture, biomedical engineering, and energy systems, where combining lightweight structures with high-performance functionality is crucial. This invention proposes an innovative concept and method for the rapid and accurate fabrication of lightweight, sustainable, and environmentally friendly aerogels with outstanding EMI shielding and energy harvesting properties, making them suitable for use in bioelectronic components. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a preparation method and application of chitosan / MXene aerogel by ink direct writing 3D printing.

[0007] The present invention is achieved by providing a method for preparing chitosan / MXene aerogel ink direct writing 3D printing, wherein the method comprises the following steps:

[0008] Step 1, Ti3C2T x Synthesis of

[0009] 1 g of LiF was introduced into a Teflon container containing 20 mL of HCl and stirred until completely dissolved. Subsequently, 1 g of MAX (Ti3AlC2) powder was gradually added to the solution and the mixture was continuously stirred at 35 °C for 48 h. After this reaction period, the mixture was repeatedly washed and centrifuged with deionized water until the pH value of the supernatant reached 6. The supernatant was decanted, leaving a precipitate consisting of multilayer MXene. These sediments were collected and centrifuged at a high speed of 10,000 rpm for 60 minutes to ensure homogeneity and remove any bubbles or undissolved particles / aggregates that may have formed during the re-dissolution process. The resulting concentrated multilayer MXene, with a concentration of 21.56 wt%, was named Ti3C2T x .

[0010] Step 2: Chitosan / Ti3C2T x Preparation of ink.

[0011] They were prepared by dissolving a precursor solution containing 0.1% chitosan and the required amount of MXene in 1 vol% acetic acid at 60°C with continuous stirring overnight. The mixture was then freeze-dried. The dried nanocomposites were reconstituted in deionized water to achieve a solid content of 3 wt%. The resulting sols, designated CM1, CM2, CM5, and CM10, correspond to MXene to chitosan weight ratios of 1:99, 2:98, 5:95, and 10:90, respectively. The chitosan sample without any MXene was designated CS. After reconstitution, the sols were centrifuged at 1000 rpm for 10 minutes and stored at 4°C for subsequent use.

[0012] Further, 3D printing of chitosan / Ti3C2Tx ink;

[0013] The chitosan / MXene ink was 3D printed using an Axo A3 bioprinting platform from Axolotl Biosystems Ltd., equipped with a G22 conical nozzle. Samples were printed at 25°C at a print speed of 3 mm / s. Immediately after printing, the specimens were frozen at -20°C. The chitosan was deprotonated by immersing it in a cold bath of 1 M NaOH, followed by rinsing with deionized water to remove excess base, thereby inducing gelation of the 3D-printed constructs. Subsequently, the chitosan / MXene sample was re-frozen at -20°C and then freeze-dried for approximately 48 hours to obtain the desired porous 3D aerogel.

[0014] The present invention aims to provide a preparation method and application of chitosan / MXene aerogel for ink direct writing 3D printing.

[0015] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0016] First, chitosan and MXene molecules can interact with each other, which promotes the intercalation of chitosan within MXene nanosheets and leads to the expansion of the interlayer spacing.

[0017] Second, MXene significantly improves the shear-thinning properties of the ink, thereby enhancing its printability.

[0018] Third, increasing the MXene content leads to a proportional increase in the electrical conductivity of the aerogel.

[0019] The technical solution of this invention fills a technological gap in the industry both domestically and internationally: it provides a method for preparing chitosan / MXene aerogels for direct ink 3D printing. This method fills a gap in domestic chitosan / MXene aerogel manufacturing technology.

[0020] The technical solution of the present invention solves a technical problem that people have long been eager to solve but have never been able to successfully solve: the present invention solves the problem of high processing cost of chitosan / MXene aerogels that people have long been eager to solve, and creatively introduces ink direct writing 3D printing technology to successfully overcome the problem of expensive aerogel manufacturing by preparing chitosan / MXene ink.

[0021] Fourth, the dielectric constant and dielectric loss of 3D printed aerogels both increase with increasing MXene concentration.

[0022] 1) EMI shielding effect:

[0023] 28 dB was achieved when 10 wt% MXene was used.

[0024] 2) Heat resistance:

[0025] The formation of the porous structure of the aerogel promotes multiple reflections inside the material, and the thermal conductivity increases slightly with the increase of the amount of conductive nanofillers.

[0026] 3) Energy harvesting:

[0027] The printed aerogel was also integrated into the TENG system to improve its energy harvesting performance. The output voltage of the chitosan aerogel increased from 22 V to 46 V and 110 V with 1 wt% and 2 wt% MXene, respectively, while the short-circuit current increased from 0.55 μA to 1.9 μA.

[0028] The preparation method and application of ink direct writing 3D printing chitosan / MXene aerogel provided by the present invention provide new opportunities for ultra-light porous materials with excellent EMI shielding, thermal insulation and energy harvesting capabilities, making them highly applicable in both the construction and biomedical fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 This is a flow chart of preparing 3D printed chitosan / MXene aerogels according to an embodiment of the present invention;

[0031] Figure 2 This is a physical diagram provided by an embodiment of the present invention;

[0032] Figure 3 is the SEM image of aerogel;

[0033] Figure 4 is the aerogel shielding effectiveness;

[0034] Figure 5 is the thermal conductivity of the aerogel;

[0035] Figure 6 is the current curve of aerogel. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] In response to the problems existing in the prior art, the present invention provides a preparation method and application of chitosan / MXene aerogel by ink direct writing 3D printing.

[0038] like Figure 1 As shown, an embodiment of the present invention provides a method for preparing chitosan / MXene aerogel by direct-writing ink 3D printing, and the method comprises the following steps:

[0039] Step 1, synthesis of Ti3C2Tx;

[0040] 1 g of LiF was introduced into a Teflon container containing 20 mL of HCl and stirred until completely dissolved. Subsequently, 1 g of MAX (Ti3AlC2) powder was gradually added to the solution, and the mixture was continuously stirred at 35°C for 48 h. After this reaction period, the mixture was repeatedly washed and centrifuged with deionized water until the pH of the supernatant reached 6. The supernatant was decanted, leaving a precipitate consisting of multilayer MXene. These precipitates were collected and centrifuged at 10,000 rpm for 60 minutes to ensure homogeneity and remove any bubbles or undissolved particles / aggregates that may have formed during the re-dissolution process. The resulting concentrated multilayer MXene, with a concentration of 21.56 wt%, was named Ti3C2Tx.

[0041] Step 2: Preparation of chitosan / Ti3C2Tx ink.

[0042] They were prepared by dissolving a precursor solution containing 0.1% chitosan and the required amount of MXene in 1 vol% acetic acid at 60°C with continuous stirring overnight. The mixture was then freeze-dried. The dried nanocomposites were reconstituted in deionized water to achieve a solid content of 3 wt%. The resulting sols, designated CM1, CM2, CM5, and CM10, correspond to MXene to chitosan weight ratios of 1:99, 2:98, 5:95, and 10:90, respectively. The chitosan sample without any MXene was designated CS. After reconstitution, the sols were centrifuged at 1000 rpm for 10 minutes and stored at 4°C for subsequent use.

[0043] Further, 3D printing of chitosan / Ti3C2Tx ink;

[0044] The chitosan / MXene ink was 3D printed using an Axo A3 bioprinting platform from Axolotl Biosystems Ltd., equipped with a G22 conical nozzle. Samples were printed at 25°C at a print speed of 3 mm / s. Immediately after printing, the specimens were frozen at -20°C. The chitosan was deprotonated by immersing it in a cold bath of 1 M NaOH, followed by rinsing with deionized water to remove excess base, thereby inducing gelation of the 3D-printed constructs. Subsequently, the chitosan / MXene sample was re-frozen at -20°C and then freeze-dried for approximately 48 hours to obtain the desired porous 3D aerogel.

[0045] Example 1

[0046] This embodiment provides a method for preparing chitosan / MXene aerogel by direct-writing ink 3D printing. The method comprises the following steps:

[0047] Step 1, synthesis of Ti3C2Tx;

[0048] 1 g of LiF was introduced into a Teflon container containing 20 mL of HCl and stirred until completely dissolved. Subsequently, 1 g of MAX (Ti3AlC2) powder was gradually added to the solution, and the mixture was continuously stirred at 35°C for 48 h. After this reaction period, the mixture was repeatedly washed and centrifuged with deionized water until the pH of the supernatant reached 6. The supernatant was decanted, leaving a precipitate consisting of multilayer MXene. These precipitates were collected and centrifuged at 10,000 rpm for 60 minutes to ensure homogeneity and remove any bubbles or undissolved particles / aggregates that may have formed during the re-dissolution process. The resulting concentrated multilayer MXene, with a concentration of 21.56 wt%, was named Ti3C2Tx.

[0049] Step 2: Preparation of chitosan / Ti3C2Tx ink.

[0050] They were prepared by dissolving a precursor solution containing 0.1% chitosan and the required amount of MXene in 1 vol% acetic acid at 60°C with continuous stirring overnight. The mixture was then freeze-dried. The dried nanocomposites were reconstituted in deionized water to achieve a solid content of 3 wt%. The resulting sols, designated CM1, CM2, CM5, and CM10, correspond to MXene to chitosan weight ratios of 1:99, 2:98, 5:95, and 10:90, respectively. The chitosan sample without any MXene was designated CS. After reconstitution, the sols were centrifuged at 1000 rpm for 10 minutes and stored at 4°C for subsequent use.

[0051] Further, 3D printing of chitosan / Ti3C2Tx ink;

[0052] The chitosan / MXene ink was 3D printed using an Axo A3 bioprinting platform from Axolotl Biosystems Ltd., equipped with a G22 conical nozzle. Samples were printed at 25°C at a print speed of 3 mm / s. Immediately after printing, the specimens were frozen at -20°C. The chitosan was deprotonated by immersing it in a cold bath of 1 M NaOH, followed by rinsing with deionized water to remove excess base, thereby inducing gelation of the 3D-printed constructs. Subsequently, the chitosan / MXene sample was re-frozen at -20°C and then freeze-dried for approximately 48 hours to obtain the desired porous 3D aerogel.

[0053]

Claims

1. A method for preparing chitosan / MXene aerogel using direct ink writing DIW 3D printing, characterized in that: The method for preparing chitosan / MXene aerogel using direct ink writing DIW 3D printing comprises the following steps: Step 1, synthesis of Ti3C2Tx; Step 2, preparation of chitosan / Ti3C2Tx ink; Step 3: 3D printing of chitosan / Ti3C2Tx ink.

2. A chitosan / MXene aerogel prepared by direct ink writing (DIW) 3D printing as claimed in claim 1, characterized in that: An EMI shielding effect of 28 dB was achieved when using 10 wt% MXene.

3. The method for preparing chitosan / MXene aerogel using direct ink writing (DIW) 3D printing according to claim 2, wherein: It contains a porous structure, which promotes multiple reflections inside the material. Its heat resistance performance increases slightly with the increase of the amount of conductive nanofiller, and the thermal conductivity increases slightly.

4. The method for preparing chitosan / MXene aerogel using direct ink writing (DIW) 3D printing according to claim 2, wherein: It was also integrated into the TENG system to improve its energy harvesting performance. The output voltage of chitosan aerogel increased from 22 V to 46 V and 110 V with 1 wt% and 2 wt% MXene, respectively, while the short-circuit current increased from 0.55 μA to 1.9 μA.

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