Preparation method and application of green and environment-friendly layer-by-layer assembled multifunctional fabric

Abstract

This invention proposes a general strategy based on layer-by-layer (LBL) assembly to prepare flexible, multifunctional fabrics that combine motion / health monitoring and fire alarm functions. The coating formulation is environmentally friendly, fluorine-free, and halogen-free: first, reduced graphene oxide (RGO) is deposited on the fiber surface to construct a conductive network; then, a hydrogel layer is introduced; and finally, a hydrophobic surface is grafted via chemical vapor deposition (CVD) to obtain the RHP fabric. This fabric achieves a limiting oxygen index (LOI) of 42.3%, a 213% improvement over the original sample (19.9%), and exhibits excellent flame retardant properties. It also possesses a linear operating range of 100% strain, a high specification factor (GF=90.3), and a fast response / recovery time. Furthermore, the RHP fabric enables precise temperature sensing and exhibits a stable resistivity-temperature relationship. When integrated into fire-fighting suits, it can rapidly trigger a fire alarm upon flame exposure and achieve self-extinguishing flames. This layered design provides a scalable blueprint for the fabrication of high-performance multifunctional fire alarm systems and intelligent protective clothing.

Description

Technical Field

[0001] This invention belongs to the field of multifunctional fabric preparation, specifically relating to a multifunctional fabric and its preparation method. Background Technology

[0002] Driven by rapid technological advancements and increasingly diverse human needs, fabrics have long transcended their traditional role of providing warmth and basic protection, evolving into intelligent, functional, and high-performance systems. Multifunctional fabrics are now a leading research frontier and industrial frontier in modern textile science and materials engineering. Products derived from these fabrics are widely used in smart wearable devices, smart home systems, medical, fire protection, and other fields. In this evolution, several noteworthy manufacturing methods have been explored—impregnation, sol-gel, and in-situ polymerization, among others—to create precisely functionalized fabrics. However, insufficient synergistic performance remains a key bottleneck. Traditional functionalization strategies, while imparting specific properties, struggle to achieve multifunctional integration: physical or chemical incompatibilities often arise between different materials. Therefore, innovative fabrication strategies that achieve precise and orderly integration of multifunctional units while maintaining the inherent comfort of the fabric have become a core driving force for advancing multifunctional fiber textiles. Among advanced technologies, layer-by-layer assembly (LbL) stands out due to its unparalleled flexibility and controllability, providing an ideal platform for the synergistic construction of multifunctional fabrics. Achieving fabrics that inherently combine flame retardancy, conductivity, and hydrophobicity remains challenging; traditional approaches rely on complex processes involving fluorine, halogens, and organic solvents, which can endanger human health, pollute the environment, and hinder the efficient use of resources.

[0003] In recent years, although multifunctional fabric systems have shown great potential in modern materials engineering, there has been limited research on applications that combine excellent flame retardancy with multifunctionality. Furthermore, challenges remain in constructing surface coatings: layer-by-layer assembly makes it difficult to control the coating thickness, and introducing one function often compromises another. Therefore, achieving synergy between components and excellent multifunctionality in multifunctional fabric systems is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a green and environmentally friendly method for preparing a multifunctional fabric using a layer-by-layer assembly process and its applications. The multifunctional fabric provided by this invention possesses flame-retardant, conductive, and hydrophobic properties, as well as excellent temperature-sensitive properties, thus having significant application value in areas such as fire-fighting clothing materials. This invention utilizes a layer-by-layer assembly method to assemble RGO, a hydrogel coating, and polysiloxane grafted molecules in a green and environmentally friendly manner. The resulting multifunctional fabric exhibits excellent flame-retardant properties and a self-extinguishing flame function. This invention features a green and environmentally friendly process, is simple to implement, and has broad application prospects in the field of multifunctional fabrics. To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0005] (1) GO fabric is prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying, the GO fabric is immersed in ascorbic acid solution to reduce it to RGO fabric.

[0006] (2) Mix deionized water, sodium chloride (NaCl) and phytic acid (PA) solution and stir until dissolved. After cooling, add acrylamide, N,N'-methylenebisacrylamide (crosslinking agent) and ammonium persulfate (initiator) and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) in the prepared solution and heat to dry to obtain RH fabric.

[0007] (3) Tetraethoxysilane (TEOS) was mixed with ethanol at room temperature. After heating, water and acetic acid were added, and the mixture was cooled to room temperature after stirring. The RH fabric obtained in step (2) was immersed in the mixture and then removed and dried by heating. The pretreated fabric was placed in a sealed glass container to avoid contact with dichlorodimethylsilane and subjected to room temperature chemical vapor deposition.

[0008] The multifunctional fabric provided by this invention exhibits excellent flame retardant properties, with a limiting oxygen index (LOI) of 42.3%, a 213% improvement over the original sample (19.9%). It also features a wide linear operating range (100% strain), good GF (gauge factor: 90.3), and fast response / recovery time. It provides accurate temperature sensing with a stable resistivity-temperature correlation. Furthermore, it possesses good hydrophobic properties, with a hydrophobic angle exceeding 107°. The preparation method of this invention is simple, environmentally friendly, and suitable for industrial production and market application.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] (1) The present invention successfully constructed a green multilayer structure by attaching RGO, hydrogel coating and polysiloxane graft copolymer to the surface of RHP fabric through a layer-by-layer assembly process.

[0011] (2) The present invention has multiple functions, excellent flame retardancy and self-extinguishing properties, good hydrophobicity and conductivity.

[0012] (3) As a temperature sensor, the present invention has good thermal response and stable temperature resistance correlation, can achieve stable signal output, and provide protection and signal transmission in high temperature environment. Attached Figure Description

[0013] Figure 1 Design concept of multifunctional RHP fabric in Example 1

[0014] Figure 2 This is the SEM image of the unprocessed fabric in Example 1;

[0015] Figure 3 The image shows the SEM image of the fabric after layer-by-layer assembly in Example 1.

[0016] Figure 4 EDS image of the fabric after layer-by-layer assembly in Example 1;

[0017] Figure 5 The HRR graphs for the ordinary fabric and the RHP fabric after the cone burning test in Example 2 are shown.

[0018] Figure 6 The THR diagrams for the ordinary fabric and the RHP fabric after the cone burning test in Example 2 are shown.

[0019] Figure 7 Mass graphs of ordinary fabric and RHP fabric after the cone burning test in Example 2;

[0020] Figure 8 The GF diagram of the RHP fabric in Example 3;

[0021] Figure 9 The ΔR / R0 of the RHP fabric in Example 3 at 25℃-100℃;

[0022] Figure 10 This is a comparison of the hydrophobicity of ordinary fabric and RHP fabric in Example 4;

[0023] Figure 11 The diagram shows the alarm response of RHP fabric as a fire alarm simulator in Example 5. Detailed Implementation

[0024] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0025] Example 1: A method for preparing a green and environmentally friendly multi-functional fabric assembled layer by layer, the specific steps of which are as follows:

[0026] (1) GO fabric was prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying at 60°C for 12 h, the GO fabric was immersed in ascorbic acid solution at 60°C for 12 h to reduce it to RGO fabric.

[0027] (2) Mix 3 mL of deionized water, 0.32 g of sodium chloride (NaCl), and 10 mL of phytic acid (PA) solution, and stir until dissolved. After cooling, add 2 g of acrylamide, 0.01 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.01 g of ammonium persulfate (initiator), and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) into the prepared solution and heat at 60°C to obtain RH fabric.

[0028] (3) Mix 10.42 g of tetraethoxysilane (TEOS) with 8.74 g of ethanol for 1 min at room temperature. Heat to 60 °C, add water and acetic acid, stir at 60 °C for 3 h, and cool to room temperature. Immerse the RH fabric obtained in step (2) in water for 5 min, remove it, and heat at 90 °C for 10 min. Place the pretreated fabric in a sealed glass container to avoid contact with dichlorodimethylsilane, and perform room temperature chemical vapor deposition to obtain RHP fabric. The specific design idea is as follows: Figure 1 As shown.

[0029] The SEM image of the ordinary fabric in Example 1 (e.g.) Figure 2 (as shown) and SEM images of multifunctional RHP fabrics (e.g.) Figure 3 Comparing the two fabrics (as shown), it can be observed that the untreated fabric surface lacks fiber-to-fiber bonding and exhibits no obvious micro- or nano-scale roughness; while the fabric surface after layer-by-layer assembly shows fiber bonding, functional materials distributed on individual fibers, and a significant micro- or nano-scale roughness. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed the coexistence of characteristic components on the RHP fabric, such as... Figure 4 As shown, carbon is derived from the RGO, phosphorus and sodium from the hydrogel, and silicon from the polysiloxane-branched molecular layer. Notably, carbon and sodium are crucial for conductivity, phosphorus provides flame retardancy, and the polysiloxane-branched molecular layer structure imparts strong hydrophobicity. Their uniform distribution in the elemental mapping confirms successful functionalization through layer-by-layer assembly.

[0030] Example 2: A method for preparing a green and environmentally friendly multi-functional fabric assembled layer by layer, the specific steps of which are as follows:

[0031] (1) GO fabric was prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying at 60°C for 12 h, the GO fabric was immersed in ascorbic acid solution at 60°C for 12 h to reduce it to RGO fabric.

[0032] (2) Mix 3 mL of deionized water, 0.32 g of sodium chloride (NaCl), and 10 mL of phytic acid (PA) solution, and stir until dissolved. After cooling, add 2 g of acrylamide, 0.01 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.01 g of ammonium persulfate (initiator), and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) into the prepared solution and heat at 60°C to obtain RH fabric.

[0033] (3) Mix 10.42 g of tetraethoxysilane (TEOS) with 8.74 g of ethanol for 1 min at room temperature. Heat to 60 °C, add water and acetic acid, stir at 60 °C for 3 h, and cool to room temperature. Immerse the RH fabric obtained in step (2) in water for 5 min, remove it, and heat at 90 °C for 10 min. Place the pretreated fabric in a sealed glass to avoid contact with dichlorodimethylsilane, and perform room temperature chemical vapor deposition to obtain the RHP fabric.

[0034] In accordance with ISO 5600-1 standard, a cone calorimeter was used to conduct more rigorous tests on the original and modified fabrics. Figure 5 The heat release rate curve shows that the original fabric burned rapidly, with a high and steep peak heat release rate (PHRR) appearing after only 76 s of heat exposure. This peak corresponds to 387.79 kW·m. -2 The RHP fabric exhibits a high instantaneous heat release rate. Compared to untreated fabrics, the heat release rate curve of the RHP fabric is flatter, and the release process is more stable. After 199 s of heat treatment, its instantaneous heat release rate remains at a low level (78.97 kW·m). -2 ). Figure 6 The cumulative heat data shown confirms that the total heat release rate (THR) of RHP fabric is significantly reduced (25.85 MJ·m). -2 ), compared to the original fabric (44.20 MJ·m -2 The fire rate reduction is nearly halved. The Fire Growth Rate Index (FIGRA) is another key indicator for assessing fire risk, calculated as PHRR / TPHRR. Calculations show that the FIGRA value of the original fabric is 5.10 kW·m. -2 ·s -1 After modification and fabrication into RHP fabric, the efficiency was reduced to 0.39 kW·m. -2 ·s -1 Furthermore, the study found that the weight loss rates of the original fabric and the RHP fabric were comparable within the initial 54 seconds, such as... Figure 7 As shown. In this subsequent stage, the weight loss rate of the RHP fabric was significantly inhibited, which may be attributed to the protective carbon layer. Therefore, the RHP fabric exhibited excellent protective performance throughout the combustion process, with a carbonization residue rate of 45.3%, while the residue rate of the original fabric was below the measurable range (<3%).

[0035] Example 3: A method for preparing a green and environmentally friendly multi-functional fabric assembled layer by layer, the specific steps of which are as follows:

[0036] (1) GO fabric was prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying at 60°C for 12 h, the GO fabric was immersed in ascorbic acid solution at 60°C for 12 h to reduce it to RGO fabric.

[0037] (2) Mix 3 mL of deionized water, 0.32 g of sodium chloride (NaCl), and 10 mL of phytic acid (PA) solution, and stir until dissolved. After cooling, add 2 g of acrylamide, 0.01 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.01 g of ammonium persulfate (initiator), and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) into the prepared solution and heat at 60°C to obtain RH fabric.

[0038] (3) Mix 10.42 g of tetraethoxysilane (TEOS) with 8.74 g of ethanol for 1 min at room temperature. Heat to 60°C, add water and acetic acid, stir at 60°C for 3 h, and cool to room temperature. Immerse the RH fabric obtained in step (2) in water for 5 min, remove it, and heat at 90°C for 10 min. Place the pretreated fabric in a sealed glass container to avoid contact with dichlorodimethylsilane, and perform room temperature chemical vapor deposition to obtain the RHP fabric.

[0039] GF is calculated using ΔR / R0 (GF = (ΔR / R0)), where ΔR = R − R0, R and R0 represent the real-time resistance and initial resistance, respectively, and ε represents the applied tensile strain. Figure 8 As shown, the tensile strain of the RHP fabric continuously increases. The GF value of the RHP fabric can be calculated from ΔR / R0 and the tensile strain. The GF value of the RHP fabric varies in different strain ranges. The results show that the GF value reaches 14.6 in the strain range of 0%-20%. When the strain range increases from 20% to 60%, the GF value rises to 73.9. Further expanding the strain range from 50% to 100%, the GF value of the RHP fabric reaches 90.3.

[0040] The temperature-sensing properties of RHP fabric were measured by placing it on a hot plate, such as... Figure 9 As shown, due to the significant differences in resistance response, the fabric effectively distinguishes samples within the 25-100°C range; at 100°C, the relative resistance change rate reaches a peak of 57.836%. Measuring the absolute temperature coefficient of resistance (|TCR|) of the RHP fabric directly reflects the rate of change of resistance with temperature, reaching 1.45%°C within a narrow window of 25-30°C.-1 The |TCR| gradually decreases with every 10°C increase, stabilizing at 60°C; |TCR| reaches 0.73%°C. -1 The material maintains a stable resistance-temperature relationship and fully recovers its initial resistance.

[0041] Example 4: A method for preparing a green and environmentally friendly multi-functional fabric assembled layer by layer, the specific steps of which are as follows:

[0042] (1) GO fabric was prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying at 60°C for 12 h, the GO fabric was immersed in ascorbic acid solution at 60°C for 12 h to reduce it to RGO fabric.

[0043] (2) Mix 3 mL of deionized water, 0.32 g of sodium chloride (NaCl), and 10 mL of phytic acid (PA) solution, and stir until dissolved. After cooling, add 2 g of acrylamide, 0.01 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.01 g of ammonium persulfate (initiator), and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) into the prepared solution and heat at 60°C to obtain RH fabric.

[0044] (3) Mix 10.42 g of tetraethoxysilane (TEOS) with 8.74 g of ethanol for 1 min at room temperature. Heat to 60°C, add water and acetic acid, stir at 60°C for 3 h, and cool to room temperature. Immerse the RH fabric obtained in step (2) in water for 5 min, remove it, and heat at 90°C for 10 min. Place the pretreated fabric in a sealed glass container to avoid contact with dichlorodimethylsilane, and perform room temperature chemical vapor deposition to obtain the RHP fabric.

[0045] like Figure 10 As shown, RHP fabrics exhibit excellent resistance to staining by tea, milk, coffee, and other liquids, with a contact angle exceeding 107°. In contrast, untreated fabrics were easily absorbed by the same liquids, leaving noticeable stains. Furthermore, RHP fabrics prepared via chemical vapor deposition retained dye droplets on their surface, attributed to their superior hydrophobicity compared to untreated fabrics.

[0046] Example 5: A method for preparing a green and environmentally friendly multi-functional fabric assembled layer by layer, the specific steps of which are as follows:

[0047] (1) GO fabric was prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying at 60°C for 12 h, the GO fabric was immersed in ascorbic acid solution at 60°C for 12 h to reduce it to RGO fabric.

[0048] (2) Mix 3 mL of deionized water, 0.32 g of sodium chloride (NaCl), and 10 mL of phytic acid (PA) solution, and stir until dissolved. After cooling, add 2 g of acrylamide, 0.01 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.01 g of ammonium persulfate (initiator), and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) into the prepared solution and heat at 60°C to obtain RH fabric.

[0049] (3) Mix 10.42 g of tetraethoxysilane (TEOS) with 8.74 g of ethanol for 1 min at room temperature. Heat to 60°C, add water and acetic acid, stir at 60°C for 3 h, and cool to room temperature. Immerse the RH fabric obtained in step (2) in water for 5 min, remove it, and heat at 90°C for 10 min. Place the pretreated fabric in a sealed glass container to avoid contact with dichlorodimethylsilane, and perform room temperature chemical vapor deposition to obtain the RHP fabric.

[0050] like Figure 11 As shown, an alarm response system was simulated: relying on the conductive network composed of RGO nanosheets, RHP fabric exhibits excellent thermoelectric properties. When one end of the fabric is exposed to a flame, the graphene oxide (GO) undergoes a transformation under thermal activation. As the temperature rises, the disordered graphene oxide structure gradually transforms into a graphite-like ordered honeycomb lattice, forming a more continuous sp² hybrid carbon network. This process reduces the fabric's resistance and significantly improves its conductivity. The excellent flame-retardant properties and the thermoelectric effect induced by the resistance difference make RHP fabric a promising candidate for fire alarm systems. We constructed a resistance measurement fire alarm device with a built-in buzzer, which can monitor resistance changes in real time. When the resistance value is lower than a preset threshold, the signal detection switch closes to form a loop, triggering a flashing light and an audible alarm. Under ambient conditions, the device recorded a stable resistance value of 460 Ω, and the AL1 warning light remained off. When heated by an alcohol lamp, the resistance value of the RHP fabric decreased. Once the resistance fell below the preset lower limit of 300 Ω, the AL1 indicator light immediately activated and triggered the buzzer alarm. After the flame is extinguished, when the temperature returns to ambient levels, oxygen molecules or moisture in the environment may be re-adsorbed onto the RGO surface, partially repairing the damaged functional group structure. This dynamic equilibrium causes the resistance to tend towards its initial state.

[0051] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A green and environmentally friendly multi-functional fabric assembled layer by layer: characterized in that: The fabric surface has multiple properties such as flame retardancy, conductivity, and hydrophobicity.

2. The green and environmentally friendly multi-functional fabric assembled layer by layer according to claim 1, characterized in that, The original fabric had a LOI of 19.9%. After layer-by-layer assembly, the LOI of the multifunctional RHP (RGO-Hydrogel-Polysiloxane) fabric increased to 42.3%. This improvement corresponds to a 212.2% LOI enhancement. According to ISO 5600-1 standard, the total heat release rate (THR) of the RHP fabric was significantly reduced (25.85 MJ·m). -2 ), compared to the original fabric (44.20 MJ·m -2 The resistivity is nearly halved. It features a good GF (gain factor: 90.3) and fast response / recovery time. It provides accurate temperature sensing with a stable resistivity-temperature correlation. It has water-repellent protection properties and a contact angle exceeding 107°.

3. A method for preparing a green and environmentally friendly multifunctional fabric based on layer-by-layer assembly as described in any one of claims 1-2, characterized in that... Multifunctional fabrics are fabricated through vacuum filtration, in-situ gelation, and layer-by-layer assembly using chemical vapor deposition.

4. The method according to claim 3, characterized in that, The specific steps are as follows: (1) GO fabric is prepared by vacuum filtering graphene oxide onto ordinary fabric. After drying, the GO fabric is immersed in ascorbic acid solution to reduce it to RGO fabric. (2) Mix deionized water, sodium chloride (NaCl) and phytic acid (PA) solution and stir until dissolved. After cooling, add acrylamide, N,N'-methylenebisacrylamide (crosslinking agent) and ammonium persulfate (initiator) and stir until dissolved. Finally, immerse the RGO fabric obtained in step (1) into the prepared solution and heat to dry to obtain RH (RGO-Hydrogel) fabric. (3) Tetraethoxysilane (TEOS) was mixed with ethanol at room temperature. After heating, water and acetic acid were added, and the mixture was cooled to room temperature after stirring. The RH fabric obtained in step (2) was immersed in the mixture and then removed and dried by heating. The pretreated fabric was placed in a sealed glass container to avoid contact with dichlorodimethylsilane and subjected to room temperature chemical vapor deposition. The RHP fabric was finally obtained.

5. The green layered multifunctional fabric prepared by the preparation method of claim 4 is used for fire protection clothing.

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