Layered structure based on nanoscale particulate electrostatic filtration

Abstract

This invention provides a layered structure based on electrostatic filtration of nanoscale particles, relating to the field of electrostatic filtration technology. The layered structure connects an electrostatic adsorption layer and a flexible electrode layer to the two poles of a power supply component, with an insulating layer between the electrostatic adsorption layer and the flexible electrode layer. Combined with the gap-micropore dual-level porous structure and high-density electrostatic micronodes of the electrostatic adsorption layer, voltage focusing technology achieves uniform polarization across the entire electrostatic adsorption layer, eliminating adsorption blind zones and enabling efficient and long-lasting filtration of 0.075-100nm nanoparticles. The mask fabricated using this layered structure balances high-efficiency filtration with long-term wearing comfort, significantly improving the technical contradiction of high efficiency but high resistance in existing masks, making it suitable for prolonged industrial work.

Description

Technical Field

[0001] This invention relates to the field of electrostatic filtration technology, and more specifically to a layered structure based on electrostatic filtration of nanoscale particles. Background Technology

[0002] In multiple fields such as air purification, water treatment, industrial precision manufacturing, and medical protection, the efficient filtration and removal of nanoscale particles (including nanoscale particles, heavy metal ions, and harmful molecules) has always been a core requirement for ensuring product quality, environmental safety, and human health.

[0003] With the advancement of industrialization and increasingly stringent environmental standards, the harm of nanoscale pollutants such as silica dust (0.075-100nm) and coal dust to the ecological environment and human health is becoming increasingly prominent. Statistics show that millions of people worldwide suffer from cardiovascular and respiratory diseases each year due to inhaling air polluted with nanoscale particles. Furthermore, nanoscale particle pollution in industrial production is a key factor contributing to decreased yield rates in precision manufacturing industries such as display panels and semiconductors, causing significant economic losses to companies.

[0004] Existing layered filter structures are ineffective at filtering nanoscale particles and have a short lifespan. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a layered structure based on electrostatic filtration of nano-sized particles, which solves the problems of poor filtration effect and short service life of layered filtration structures for nano-sized particles.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A layered structure based on electrostatic filtration of nano-sized particles, the layered structure comprising, from the outside to the inside: an antistatic protective layer, an electrostatic adsorption layer, an insulating layer, a flexible electrode layer, a skin-friendly and waterproof layer, and a power supply component;

[0008] The two poles of the power supply component are respectively connected to an electrostatic adsorption layer and a flexible electrode layer;

[0009] The antistatic protective layer, electrostatic adsorption layer, insulating layer, flexible electrode layer, and skin-friendly waterproof layer are prepared by an integrated molding process of in-situ polymerization and vacuum filtration, without any layer gaps.

[0010] Preferably, the electrostatic adsorption layer is a composite porous membrane of reduced graphene oxide / nitrogen-doped graphene quantum dots; wherein, the reduced graphene oxide forms a three-dimensional interconnected framework with an interlaced network sheet structure, the degree of reduction is 70%-80%, and some hydroxyl and epoxy oxygen-containing functional groups are retained; the nitrogen-doped graphene quantum dots are uniformly embedded in the surface, gaps and micropore edges of the reduced graphene oxide sheets in a monodisperse state, and are in-situ blended with the reduced graphene oxide through π-π stacking.

[0011] Preferably, the antistatic protective layer is a customized waterproof and insulating PVDF composite coating, which is modified by adding 0.5% nano silica and 1% fluorocarbon waterproofing agent, and micro-bumps are set on the surface of the antistatic protective layer.

[0012] Preferably, the insulating layer is a waterproof PI film or an electrospun PLA film with a thickness of 1-2 μm and a microporosity of ≥70%, which is closely bonded to the electrostatic adsorption layer and the flexible electrode layer.

[0013] Preferably, the middle region of the flexible electrode layer adopts a dotted or grid-like discontinuous distribution design, and the material is a graphene-coated PI film or a carbon nanotube-coated PI film with a thickness of 1-1.2 μm, with a 5-8 mm wide continuous conductive area reserved at the edge.

[0014] Preferably, the skin-friendly waterproof layer is a waterproof pure cotton blend composite film, modified by adding 0.8% organosilicon waterproofing agent, with a thickness of 2-3 μm and a volume resistivity ≥10. 10 Ω·cm, air permeability ≥300mm / s under 200Pa pressure.

[0015] Preferably, the power supply component includes: a flexible thin-film battery, an overcurrent protection resistor, a Zener diode, and a switch;

[0016] The flexible thin-film battery, overcurrent protection resistor, Zener diode and switch are connected in series by wires;

[0017] The connection between the power supply component and the electrostatic adsorption layer is located in the edge region of the electrostatic adsorption layer away from the insulating layer, and the connection between the power supply component and the flexible electrode layer is located in the continuous conductive region at the edge of the flexible electrode layer.

[0018] Preferably, the layered structure is applied to a disposable industrial electrostatic dust removal mask, which comprises, from the outside to the inside: an outer protective fabric, a layered structure, a middle support mesh, and an inner skin-friendly fabric.

[0019] The outer protective fabric is made of polyester fiber with a thickness of 5-8μm; the middle support mesh is made of polyamide with a mesh size of 100-200μm; the inner skin-friendly fabric is made of pure cotton blend with a thickness of 3-5μm and is only distributed in the face-fitting area of ​​the mask base. The non-face-fitting filter cavity area of ​​the mask is only provided with the outer protective fabric, layered structure and middle support mesh.

[0020] Preferably, the method for preparing the layered structure includes:

[0021] Through an integrated molding process of in-situ polymerization and vacuum filtration, an antistatic protective layer, an electrostatic adsorption layer, an insulating layer, a flexible electrode layer, and a skin-friendly waterproof layer are sequentially deposited on the filter membrane under conditions of vacuum degree -0.09~-0.08MPa, polymerization temperature 58-62℃, and heat preservation time 1.5-2.5h.

[0022] The method for preparing the raw materials for the electrostatic adsorption layer includes:

[0023] Mix graphene oxide dispersion with nitrogen-doped graphene quantum dots at a mass ratio of 95:5, ultrasonically disperse for 25-35 min, adjust pH to 6.3-6.7, add reducing agent vitamin C, and reduce at 60℃ for 1.5-2.5 h, with the degree of reduction controlled at 70-80%.

[0024] Preferably, the electrostatic adsorption layer is a nanofiber / electrospun PVDF composite membrane, which is prepared by electrospinning nanofiber and PVDF electret in a mass ratio of 1:9, with parameters of spinning voltage of 18~22kV, solution flow rate of 0.8~1.2mL / h, receiving distance of 15~20cm, to form a membrane with a thickness of 12-15μm.

[0025] This invention provides a layered structure based on electrostatic filtration using nanoscale particles. Compared with existing technologies, it has the following advantages:

[0026] In this invention, the layered structure connects an electrostatic adsorption layer and a flexible electrode layer to the two poles of the power supply component, respectively, with an insulating layer between the electrostatic adsorption layer and the flexible electrode layer. Combined with the gap-micropore dual-level porous structure and high-density electrostatic micronodes of the electrostatic adsorption layer, voltage focusing technology achieves uniform polarization across the entire electrostatic adsorption layer, eliminating adsorption blind zones and enabling efficient and long-lasting filtration of 0.075-100nm nanoparticles. The mask prepared using this layered structure balances efficient filtration with long-term wearing comfort, significantly improving the technical contradiction of high efficiency but high resistance in existing masks, making it suitable for long-term industrial operations. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an exploded view of the layered structure in Embodiment 1 of the present invention.

[0029] Figure 2 This is a schematic diagram of the electrostatic adsorption layer in Embodiment 1 of the present invention.

[0030] Figure 3 This is a schematic diagram of the structure of a disposable industrial electrostatic dust removal mask in an embodiment of the present invention.

[0031] Figure 4 This is a schematic diagram of the internal structure of a disposable industrial electrostatic dust removal mask in an embodiment of the present invention.

[0032] Figure 5 This is a comparison table of Embodiment 1, Comparative Example 1, Embodiment 10, and Comparative Example 2 of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] This application provides a layered structure based on electrostatic filtration of nano-sized particles, which solves the problems of poor filtration effect and short service life of layered filtration structures for nano-sized particles.

[0035] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0036] Example 1:

[0037] like Figure 1 , Figure 2 As shown, the present invention provides a layered structure based on electrostatic filtration of nano-sized particles. The layered structure comprises, from the outside to the inside: an antistatic protective layer, an electrostatic adsorption layer, an insulating layer, a flexible electrode layer, a skin-friendly and waterproof layer, and a power supply component.

[0038] The layered structure has a total thickness of 22 μm, with the thickness of each layer adjustable by ±0.5 μm. The microporosity is 65%. It is prepared by an integrated molding process of in-situ polymerization and vacuum filtration, with a vacuum degree of -0.085 MPa, a polymerization temperature of 60℃, and a holding time of 2 hours. There are no gaps between the layers, forming a triple protective structure with a waterproof and wear-resistant outer layer, an insulating and antistatic middle layer, and a waterproof and skin-friendly inner layer. It also ensures electric field penetration and smooth airflow. Unlike existing layered spliced ​​filter layers, it has stronger structural stability and functional synergy.

[0039] The in-situ polymerization process follows the relevant methods in the OECD Guidelines for Sample Preparation and Dosimetry of Artificial Nanomaterials (2025 Edition). Using a JH-1000 composite film performance tester, the bubble ratio was measured to be <1% by microscopic observation. The micropore uniformity was measured to be 98.2%±0.3%, the reaction completion rate was 99%, the interlayer bonding force was 5.8N / 10mm, the degree of curing was 99%, the rGO sheet distribution uniformity was ≥95% (actual measurement 95%±0.5%), and the flexural strength was 510 ±12 cycles. This meets the health and safety protection requirements for nanomaterial operation sites in GB / T 33715-2025 Guidelines for Occupational Health and Safety in Nanotechnology, and can fully meet the long-term industrial operation protection and stability requirements.

[0040] The two poles of the power supply component are respectively connected to an electrostatic adsorption layer and a flexible electrode layer;

[0041] The antistatic protective layer is a customized waterproof and insulating PVDF (polyvinylidene fluoride) composite coating. It is synergistically modified by adding 0.5% nano-silica and 1% fluorocarbon waterproofing agent. Waterproof modification of PVDF coating materials is a conventional technique in this field and will not be elaborated upon further. The thickness is 1.5 μm. Abrasion resistance testing was conducted according to the current valid standard GB / T 21196.2-2007, adapting to the textile substrate material of the antistatic protective layer. A YG(B)401E Martindale abrasion tester was used, and the test was conducted under a friction load of 9N, a friction medium of pure cotton cloth, and a standard environment of 20±2℃ / 65±5%RH. The abrasion resistance was ≥500 cycles, and the volume resistivity was ≥10. 12 With a strength of Ω·cm, it provides triple protection: anti-static breakdown, prevention of external water penetration, and blocking of large dust particles to avoid clogging the electrostatic adsorption layer; the surface is equipped with micro-bumps (bump height 0.9μm) to facilitate the shaking off of attached dust and extend the service life of the filter layer; in extreme industrial environments, under 85%RH and -5℃ continuous 72h simulation using an SH-261 constant temperature and humidity chamber, the volume resistivity decreases by no more than 20%, and there is no short circuit leakage, breaking through the bottleneck of unstable performance of existing protective layers in complex environments.

[0042] like Figure 2As shown, the electrostatic adsorption layer is a composite porous membrane of reduced graphene oxide / nitrogen-doped graphene quantum dots (rGO / N-GQDs) with a thickness of 13.5 μm. The reduced graphene oxide (rGO) forms a three-dimensional interconnected framework with an interlaced network structure, a sheet thickness of 1.5 nm, and a reduction degree of 70%-80%. It retains some hydroxyl and epoxy-containing oxygen functional groups, precisely balancing framework stability, micropore connectivity, and moderate conductivity to prevent rapid electrostatic dissipation. The nitrogen-doped graphene quantum dots (N-GQDs) are uniformly embedded in the surface, gaps, and micropore edges of the reduced graphene oxide sheets in a monodisperse state. Through π-π stacking, they are in-situ blended with the reduced graphene oxide to form high-density electrostatic micronodes with a node spacing of 20-50 nm, providing stable structural support for a uniform electrostatic field.

[0043] The insulating layer is made of waterproof PI (polyimide) film with a thickness of 1.5μm and a microporosity of ≥70%. It is closely bonded to the electrostatic adsorption layer and the flexible electrode layer, which not only completely avoids short circuit between the two electrodes, but also effectively blocks water vapor penetration. It ensures the electric field penetration without increasing airflow resistance, making it suitable for humid industrial environments and solving the problems of large thickness and poor air permeability of existing insulating layers.

[0044] The flexible electrode layer adopts a dotted or grid-like discontinuous distribution design, and is made of graphene-coated PI film with a thickness of 1.1μm. Only the edges are reserved with a 5-8mm wide continuous conductive area for connecting to the power supply component wires. The discontinuous area in the middle avoids blocking the adsorption channel, ensuring smooth airflow, and at the same time allows the positive electrode electric field to diffuse evenly in all directions, realizing the full polarization of the electrostatic adsorption layer without adsorption blind spots. This is different from the defects of existing continuous electrode layers that are prone to clogging and have uneven electric field distribution.

[0045] The skin-friendly waterproof layer is made of a waterproof pure cotton blend composite membrane, modified by adding 0.8% organosilicon waterproofing agent. This waterproof modification is a conventional technique in the field and will not be elaborated upon further. It combines softness and skin-friendliness with insulation and waterproofing, has a thickness of 2.5 μm, and a volume resistivity ≥10. 10The air permeability test (Ω·cm) was conducted according to the current valid standard GB / T5453-1997 (suitable for skin-friendly waterproof fabrics). The target air permeability was set at ≥300mm / s. An LFY-216 fabric air permeability meter was used, and tests were conducted at 200Pa test pressure and 20±2℃ / 65±5%RH. The average air permeability of the three sample groups was measured to be 320mm / s. This result directly supports the rationality of the 2.5μm thickness of the skin-friendly waterproof layer, ensuring that the air permeability meets the standard while avoiding insufficient waterproofing due to insufficient thickness or insufficient air permeability due to excessive thickness. The skin irritation test was conducted according to the current valid standard GB / T 16175-2008 (Suitable for skin contact protective materials) was tested on 10 healthy subjects (5 males and 5 females, aged 20-45 years) for 24 hours. The target irritation level was set at 0. All subjects showed no irritation, redness, swelling, itching, or other symptoms at level 0. This result directly supports the rationality of the selection of the skin-friendly waterproof layer material, ensuring no discomfort during long-term contact with the face and meeting the needs of industrial long-term wear. The contact electrostatic voltage test target was set at ≤50V. Using an EST101 electrostatic voltage tester under standard conditions, the average measured voltage was 42V. This result directly supports the rationality of the insulation performance of the skin-friendly waterproof layer, avoiding discomfort or interference caused by static electricity accumulation. The skin-friendly waterproof layer's contact electrostatic voltage ≤50V effectively prevents water vapor from penetrating to the flexible electrode layer, avoiding short circuits or leakage caused by water vapor, while also preventing direct contact of static electricity with the skin.

[0046] The electrostatic adsorption layer adopts a dual-level porous structure design of "slit-micropore," which completely solves the contradiction between airflow resistance and adsorption efficiency in traditional filter layers: the reduced graphene oxide sheets interweave to form micron-level interconnected slits with a pore size of 0.5-1μm, accounting for 20%-30% of the membrane area, serving as the main airflow channels and ensuring airflow resistance ≤25Pa; nano- to submicron-level micropores with a pore size of 50-200nm are distributed inside the reduced graphene oxide sheets and at their connections, accounting for 40%-50% of the membrane area, and interconnect with the slits to form a three-dimensional adsorption network, significantly increasing the adsorption area. This ensures a filtration efficiency of ≥99.95% for 0.075μm particles. A high-field region of 10-20kV / m is formed at the slit edges due to the aggregation of reduced graphene oxide sheets. This field strength is achieved through the grid design of the flexible electrode layer and the high dielectric properties of the electrostatic adsorption layer, resulting in voltage focusing. The voltage is generated by a 3V battery, stepped down by a Zener diode, and distributed across the electrode layer, effectively regulating the voltage applied to the electrostatic adsorption layer. This precisely polarizes nanoscale particles for efficient electrostatic adsorption, while a physical barrier mechanism further enhances the filtration efficiency. The filtration efficiency test is conducted according to the current effective standard GB 2626-2019, setting a target filtration efficiency of ≥99.95%. A TSI-8130 particulate matter filtration efficiency tester is used at an airflow rate of 30L / min and a standard dust concentration of 10mg / m³ (ISO 12103-1). Tested under A1 ultrafine dust conditions, the filtration efficiency of this layer for nanoparticles of different sizes was as follows: ≥99.95% for 0.075μm particles, ≥99.94% for 0.1μm particles, ≥95% for 0.3μm particles, ≥99.98% for 1μm particles, and ≥99.99% for 10μm particles, forming a complete particle size-efficiency protection system. The saturated adsorption capacity was 1.35mg / cm² (based on a 13.5μm thickness). The electric field strength decay over time was strictly controlled within a reasonable range. According to the actual measurement with an electric field strength meter, the field strength was 12-12.5kV / m after 8 hours and 10-10.3kV / m after 10 hours, corresponding to filtration efficiencies maintained at 99.5% and 99.4%, respectively, which is significantly better than the electrostatic durability of existing electret materials.

[0047] The power supply components include: a flexible thin-film battery, an overcurrent protection resistor, a Zener diode, and a switch;

[0048] The flexible thin-film battery, overcurrent protection resistor, Zener diode, and switch are connected in series via wires.

[0049] The connection between the power supply component and the electrostatic adsorption layer is located in the edge region of the electrostatic adsorption layer away from the insulating layer, and the connection between the power supply component and the flexible electrode layer is located in the continuous conductive region at the edge of the flexible electrode layer.

[0050] The flexible thin-film battery is a 3V, 100mAh lithium-ion micro flexible thin-film battery. The battery is encapsulated with an epoxy resin coating with a coating thickness of ≤100μm, which is suitable for industrial high humidity and high dust environments. The circuit working current is ≤5mA and can provide power for more than 10 hours continuously.

[0051] The overcurrent protection resistor has a resistance of 180Ω and a rated current of 50mA. When the circuit fault current exceeds 50mA, the overcurrent protection resistor will limit the current to a safe range to prevent damage to the power supply components and ensure safe use.

[0052] The Zener diode is matched with a 2.7V Zener diode and a 3V flexible thin-film battery. After the voltage is stepped down, it is focused and conducted to the two electrodes through the grid structure of the flexible electrode layer. Under the triple protection of the antistatic protective layer, the insulating layer and the skin-friendly waterproof layer, it effectively blocks water vapor or liquid on the outside and inside, avoiding short circuits or leakage of the electrodes. At the same time, it forms a stable directional electrostatic field. The electric field penetrates the insulating layer and polarizes the rGO / N-GQDs composite membrane in the electrostatic adsorption layer, ensuring that the electrostatic field strength is stable at 10-20kV / m for 8-10 hours and the filtration efficiency is maintained at over 99.4%.

[0053] The power supply components passed electrical safety testing according to the current valid standards GB 4943.1-2022 and GB 31241-2022 (applicable to portable electrical components and lithium-ion batteries respectively). The test targets were set to meet the standards for overcharge, over-discharge, short circuit, and temperature rise. All measured items met the standard requirements. This result directly supports the rationality of the power supply components' 3V / 100mAh battery and 180Ω / 50mA protection resistor, ensuring circuit safety and stability and preventing electrical faults. The short circuit protection test set a fusing current target of 50mA, artificially simulating a short circuit fault, and monitored using a CH260 power consumption tester. The measured average fusing current was 50mA. The battery automatically melts when the current exceeds 50mA, which directly supports the rationality of the 180Ω protection resistor setting, ensuring that the power supply can be cut off in time when the circuit is short-circuited, protecting the circuit and filter structure. The power supply duration test target is ≥10h. Under the normal operating current of 4.8mA (actual value), the CH260 circuit power consumption tester was used to test the average power supply duration of 20.8h. This result directly supports the rationality of the 100mAh battery capacity, meeting the industrial single operation requirement of ≥10h and avoiding frequent replacements due to insufficient capacity.

[0054] like Figure 3 , Figure 4 As shown, the layered structure can be applied to disposable industrial electrostatic dust removal masks, which, from the outside to the inside, include: an outer protective fabric, a layered structure, a middle support mesh, and an inner skin-friendly fabric.

[0055] The outer protective fabric is made of polyester fiber with a thickness of 6.5μm, used for initial blocking of large dust particles ≥1μm to prevent premature clogging of the layered structure; the middle support mesh is made of polyamide with a mesh size of 100-200μm, possessing excellent mechanical strength and deformation adaptability, and can stably support the layered structure to prevent deformation and failure; the inner skin-friendly fabric is made of pure cotton blend with a thickness of 4μm, distributed only in the area of ​​the mask base that fits against the face, breathable and non-irritating, and the raised non-face-fitting filter area of ​​the mask only has the outer protective fabric. The outer protective fabric, layered structure, and middle support mesh, without an inner skin-friendly fabric, ensure that airflow directly enters the filtration system, avoiding the reduction in filtration efficiency caused by airflow detours. The edges of the outer protective fabric, middle support mesh, and inner skin-friendly fabric are heat-sealed with the filter cavity area (heat-sealing temperature 120℃, pressure 0.3MPa, time 10s), forming a complete disposable mask outline. The facial contact pressure is ≤1.5kPa, accurately fitting the curve of the human face, ensuring a good fit for long-term wear, and solving the problems of looseness and airflow leakage in existing masks.

[0056] The method for preparing the layered structure includes:

[0057] Through an integrated molding process of in-situ polymerization and vacuum filtration, an antistatic protective layer, an electrostatic adsorption layer, an insulating layer, a flexible electrode layer, and a skin-friendly waterproof layer are sequentially deposited on the filter membrane under conditions of vacuum degree -0.085MPa, polymerization temperature 60℃, and heat preservation time 2h.

[0058] The method for preparing the raw materials for the electrostatic adsorption layer includes:

[0059] The graphene oxide dispersion was mixed with nitrogen-doped graphene quantum dots at a mass ratio of 95:5, ultrasonically dispersed for 30 min, the pH was adjusted to 6.5, vitamin C was added as a reducing agent, and the mixture was reduced at 60℃ for 2 h, with the degree of reduction controlled at 70-80%.

[0060] In this embodiment, based on the electric field strength, the initial electric field strength of the electrostatic adsorption layer is 18 kV / m, 12.5 kV / m after 8 hours, and 10.3 kV / m after 10 hours. The initial filtration efficiency for 0.075 μm particles is 99.98%, for 0.1 μm particles is 99.96%, for 0.3 μm particles is 99.9%, for 1 μm particles is 99.99%, and for 10 μm particles is 99.99%. After 8 hours, the filtration efficiency for 0.075 μm particles is 99.5%, and after 10 hours, the filtration efficiency for 0.075 μm particles is 99.4%.

[0061] In this embodiment, the disposable industrial electrostatic dust removal mask has a breathing resistance of 22 Pa and an airflow of 32 L / min at an airflow rate of 30 L / min, providing comfortable wear without any stuffiness. The skin-friendly layer has a contact electrostatic voltage of 42 V, eliminating the risk of electrostatic irritation at the source. Even in extreme environments of 85% RH and -5℃, the volume resistivity of each insulating layer decreases by 15%, with no short circuit or leakage. At a dust concentration of 10 mg / m³... 3 It exhibits good adaptability in standard dust environments, with an adsorption capacity of less than 80% of its saturation capacity after 10 hours, eliminating the risk of clogging. It can meet the needs of long-term industrial operations, and its filtration durability is significantly better than existing electret N95 masks.

[0062] Example 2:

[0063] The difference from Example 1 is that the vacuum degree in the in-situ polymerization process is -0.08MPa, and the same detection method as in Example 1 is used to measure the bubble ratio as 5%.

[0064] Example 3:

[0065] The difference from Example 1 is that the vacuum degree in the in-situ polymerization process is -0.09MPa, and the same detection method as in Example 1 is used to measure the micropore blockage rate as 12%.

[0066] Example 4:

[0067] The difference from Example 1 is that the polymerization temperature in the in-situ polymerization process is 55°C, and the same detection method as in Example 1 is used to measure the reaction completion rate as 82% and the interlayer bonding force as 3.2 N / 10 mm.

[0068] Example 5:

[0069] The difference from Example 1 is that the polymerization temperature in the in-situ polymerization process is 65°C, and the same detection method as in Example 1 is used to measure the rGO agglomeration rate as 15% and the electrostatic node failure rate as 8%.

[0070] Example 6:

[0071] The difference from Example 1 is that the heat preservation time in the in-situ polymerization process is 1.5h, and the degree of curing is measured to be 85% using the same testing method as in Example 1.

[0072] Example 7:

[0073] The difference from Example 1 is that the heat preservation time in the in-situ polymerization process is 2.5h, and the same detection method as in Example 1 is used to measure the film embrittlement rate as 10%.

[0074] Example 8:

[0075] The difference from Example 1 is that the insulating layer is made of electrospun PLA (polylactic acid) film.

[0076] Example 9:

[0077] The difference from Example 1 is that the flexible electrode layer is made of carbon nanotube coated PI film.

[0078] Example 10:

[0079] The difference from Example 1 is that the electrostatic adsorption layer uses a nanofiber / electrospun PVDF composite membrane, specifically adapted for high-dust environments. The nanofiber forms a three-dimensional conductive network, uniformly dispersing the electric field and increasing adsorption sites, preventing electret failure caused by excessively strong local electric fields, while simultaneously strengthening the membrane's mechanical strength. The PVDF electret achieves long-term electrostatic storage through dipole orientation; both work synergistically to improve adsorption capacity and stability. It is prepared by electrospinning a 1:9 mass ratio blend of nanofiber and PVDF electret, with parameters including a spinning voltage of 20kV, a solution flow rate of 1mL / h, and a receiving distance of 17.5cm, resulting in a membrane with a thickness of 13.5μm. At 25mg / m³... 3 In high-dust environments, the filtration efficiency decay rate is 15% slower than that of the main substrate, resulting in lower mass production costs and providing diverse options for technology industrialization, thus expanding the product's applicable scenarios. The electrostatic adsorption layer, based on a thickness of 13.5 μm, has a saturated adsorption capacity of 1.35 mg / cm³. 2 Adsorption capacity per unit thickness is 0.1 mg / cm². 2 The initial electric field strength is 16 kV / m, measured in μm, and decreases to 10.5 kV / m after 8 hours. The initial filtration efficiency is 99.96% for 0.075 μm particles, 99.94% for 0.1 μm particles, 99.8% for 0.3 μm particles, 99.98% for 1 μm particles, and 99.99% for 10 μm particles. After 8 hours, the filtration efficiency for 0.075 μm particles is 99.4%, meeting the protection requirements for high-dust environments.

[0080] In this embodiment, the disposable industrial electrostatic dust removal mask exhibits a breathing resistance of 24 Pa and an airflow of 31 L / min at an airflow rate of 30 L / min, providing good wearing comfort. The skin-friendly layer has a contact electrostatic voltage of 45 V, eliminating the risk of electrostatic irritation at its source. Even in extreme environments of 85% RH and -5℃, the volume resistivity of each insulating layer decreases by 18%, with no short circuit or leakage. At a dust concentration of 25 mg / m³... 3 It exhibits excellent stability in high-dust environments, achieving 75% of its saturation capacity in 8 hours without clogging, short circuits, or electrostatic leakage. The replacement cycle precisely matches the design standards, demonstrating significant cost-effectiveness.

[0081] Example 11:

[0082] The difference from Example 1 is that the electrostatic adsorption layer thickness is 15μm (the upper limit of the main substrate thickness), the power supply component is a 3V, 100mAh lithium-ion micro flexible thin film battery, the power supply voltage is adjusted to 2.8V (the lower limit of the battery voltage), the working current is 4.5mA, the total thickness of the mask is 22μm, and the facial contact pressure is 1.5kPa.

[0083] Based on the electric field strength, the initial field strength of the electrostatic adsorption layer is 10.2 kV / m, which decreases to 9.8 kV / m after 8 hours and 9.5 kV / m after 10 hours; the initial filtration efficiency of 0.075 μm particles is 99.97%, which decreases to 99.4% after 8 hours and 99.3% after 10 hours, reaching the critical value for replacement.

[0084] In this embodiment, the disposable industrial electrostatic dust removal mask has a breathing resistance of 25Pa (critical value) and a leakage rate of 8% at an airflow rate of 30L / min; the skin-friendly layer has a contact electrostatic voltage of 48V; and the dust concentration is 10mg / m³. 3 Under standard dust conditions, the adsorption capacity reaches 80% of the saturation capacity after 10 hours, triggering the replacement mechanism.

[0085] Comparative Example 1:

[0086] Traditional industrial dust masks have a three-layer physical barrier filter structure, no electrostatic adsorption layer, external power supply components, and no clear replacement cycle. Test conditions: dust concentration 10mg / m³, airflow rate 30L / min. Test results: initial filtration efficiency of 0.075μm particles 98.5%, which drops to 89.2% after 4 hours; filtration efficiency of 0.3μm particles 94.8%; breathing resistance 35Pa; facial contact pressure 2.0kPa; skin-friendly layer contact electrostatic voltage 65V; no clear replacement cycle.

[0087] Comparative Example 2:

[0088] Traditional electrostatic filter masks have a replaceable physical adsorption filter layer and an externally mounted power supply unit with a snap-on connection, lacking a defined replacement cycle; Test conditions: dust concentration 25mg / m³ 3 The airflow rate was 30 L / min. Test results: the initial filtration efficiency for 0.075 μm particles was 98.2%, which dropped to 92.3% after 8 hours; the filtration efficiency for 0.3 μm particles was 94.5%; the breathing resistance was 38 Pa; the facial contact pressure was 2.2 kPa; the skin-friendly layer contact electrostatic voltage was 70 V; and the adsorption capacity reached 90% of the saturation capacity after 8 hours, requiring frequent replacement.

[0089] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0090] 1. In this embodiment of the invention, the layered structure connects an electrostatic adsorption layer and a flexible electrode layer to the two poles of the power supply component, respectively, with an insulating layer between the electrostatic adsorption layer and the flexible electrode layer; combined with the gap-micropore dual-level porous structure and high-density electrostatic micronodes of the electrostatic adsorption layer, voltage focusing technology is used to achieve uniform polarization of the electrostatic adsorption layer across the entire domain, with no adsorption blind spots, achieving efficient and long-lasting filtration of 0.075-100nm nanoparticles; the mask prepared using the layered structure balances efficient filtration with long-term wearing comfort, significantly improving the technical contradiction of high efficiency but high resistance in existing masks, and is suitable for long-term industrial operations.

[0091] 2. In this embodiment of the invention, the layered structure forms an all-round protection from the outside, middle and inside through a triple protection structure of antistatic protective layer, insulating layer and skin-friendly waterproof layer, completely blocking water on the outside and water vapor on the inside, avoiding electrode short circuit or leakage, and eliminating the risk of electrostatic leakage; the volume resistivity of each insulating layer does not decrease by more than 20% in extreme industrial environments, making it suitable for complex industrial scenarios such as high humidity and low temperature.

[0092] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A layered structure based on electrostatic filtration of nanoscale particles, characterized in that, The layered structure, from the outside to the inside, includes: an antistatic protective layer, an electrostatic adsorption layer, an insulating layer, a flexible electrode layer, a skin-friendly and waterproof layer, and a power supply component. The two poles of the power supply component are respectively connected to an electrostatic adsorption layer and a flexible electrode layer; The antistatic protective layer, electrostatic adsorption layer, insulating layer, flexible electrode layer, and skin-friendly waterproof layer are prepared by an integrated molding process of in-situ polymerization and vacuum filtration, without any layer gaps. The electrostatic adsorption layer is a composite porous membrane of reduced graphene oxide / nitrogen-doped graphene quantum dots. The reduced graphene oxide forms a three-dimensional interconnected framework with an interlaced network sheet structure, and the degree of reduction is 70%-80%, retaining some hydroxyl and epoxy oxygen-containing functional groups. The nitrogen-doped graphene quantum dots are uniformly embedded in the surface, gaps and micropore edges of the reduced graphene oxide sheets in a monodisperse state, and are in situ blended with the reduced graphene oxide through π-π stacking. The antistatic protective layer is a customized waterproof and insulating PVDF composite coating, which is modified by adding 0.5% nano silica and 1% fluorocarbon waterproofing agent, and micro bumps are set on the surface of the antistatic protective layer. The insulating layer is made of waterproof PI film or electrospun PLA film, with a thickness of 1-2μm and a microporosity of ≥70%, and is closely bonded to the electrostatic adsorption layer and the flexible electrode layer. The flexible electrode layer adopts a dotted or grid-like discontinuous distribution design in the middle region, and the material is a graphene-coated PI film or a carbon nanotube-coated PI film with a thickness of 1-1.2μm, with a 5-8mm wide continuous conductive area reserved at the edge. The skin-friendly waterproof layer is made of a waterproof pure cotton blend composite membrane, modified with the addition of 0.8% organosilicon waterproofing agent, with a thickness of 2-3 μm and a volume resistivity ≥10. 10 Ω·cm, air permeability ≥300mm / s under 200Pa pressure.

2. The layered structure based on electrostatic filtration of nanoscale particles as described in claim 1, characterized in that, The power supply components include: a flexible thin-film battery, an overcurrent protection resistor, a Zener diode, and a switch; The flexible thin-film battery, overcurrent protection resistor, Zener diode and switch are connected in series by wires; The connection between the power supply component and the electrostatic adsorption layer is located in the edge region of the electrostatic adsorption layer away from the insulating layer, and the connection between the power supply component and the flexible electrode layer is located in the continuous conductive region at the edge of the flexible electrode layer.

3. The layered structure based on electrostatic filtration of nanoscale particles as described in any one of claims 1-2, characterized in that, The layered structure is applied to a disposable industrial electrostatic dust removal mask, which, from the outside to the inside, includes: an outer protective fabric, a layered structure, a middle support mesh, and an inner skin-friendly fabric. The outer protective fabric is made of polyester fiber with a thickness of 5-8μm; the middle support mesh is made of polyamide with a mesh size of 100-200μm; the inner skin-friendly fabric is made of pure cotton blend with a thickness of 3-5μm and is only distributed in the face-fitting area of ​​the mask base. The non-face-fitting filter cavity area of ​​the mask is only provided with the outer protective fabric, layered structure and middle support mesh.

4. The layered structure based on electrostatic filtration of nanoscale particles as described in any one of claims 1-2, characterized in that, The method for preparing the layered structure includes: Through an integrated molding process of in-situ polymerization and vacuum filtration, an antistatic protective layer, an electrostatic adsorption layer, an insulating layer, a flexible electrode layer, and a skin-friendly waterproof layer are sequentially deposited on the filter membrane under conditions of vacuum degree -0.09~-0.08MPa, polymerization temperature 58-62℃, and heat preservation time 1.5-2.5h. The method for preparing the raw materials for the electrostatic adsorption layer includes: Mix graphene oxide dispersion with nitrogen-doped graphene quantum dots at a mass ratio of 95:5, ultrasonically disperse for 25-35 min, adjust pH to 6.3-6.7, add reducing agent vitamin C, and reduce at 60℃ for 1.5-2.5 h, with the degree of reduction controlled at 70-80%.

5. The layered structure based on electrostatic filtration of nanoscale particles as described in claim 1, characterized in that, The electrostatic adsorption layer is a nanofiber / electrospun PVDF composite membrane, which is prepared by electrospinning nanofiber and PVDF electret at a mass ratio of 1:

9. The parameters are: spinning voltage 18~22kV, solution flow rate 0.8~1.2mL / h, receiving distance 15~20cm, and a membrane thickness of 12-15μm.

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