Preparation method and application of a sweat pore-imitated nanofiber membrane

Abstract

This invention belongs to the field of high-performance fiber and fiber fabric preparation technology, specifically relating to a method for preparing a sweat-mimicking nanofiber membrane and its application in unidirectional liquid-guiding fabrics. The method involves dispersing or dissolving soluble hydrophobic polymers and micro / nano materials in a solvent to obtain an electrospinning solution; using a spinning collection device with an arrayed pore structure, electrospinning is performed to obtain the sweat-mimicking nanofiber membrane. After assembly with the fabric, the sweat-mimicking nanofiber membrane guides sweat to the detection area through both unidirectional liquid guidance and lateral drainage, enabling simultaneous detection of multiple biomarkers. This functional fabric, integrating unidirectional liquid guidance and simultaneous sweat detection, is expected to find applications in textiles, medicine, skin care, aesthetic medicine, sports medicine, aerospace, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of high-performance fiber and fiber fabric preparation technology, specifically relating to a method for preparing a sweat-mimicking nanofiber membrane and its application in unidirectional liquid-guiding fabrics. Background Technology

[0002] Sweating is a physiological function of the human body to regulate body temperature. During exercise, the skin's sweat pores secrete sweat, which evaporates to remove heat and lower skin temperature. The average person can sweat up to 1000 mL / h during moderate exercise. -1 m -2 However, if clothing fabrics cannot effectively wick away sweat from the skin's surface, excess sweat remains as adhering sweat, wetting the fabric surface to some extent and negatively impacting thermal comfort. Studies have found that varying degrees of perspiration can lead to a 2%-8% decrease in fabric thermal resistance. In low-temperature environments, this can cause a feeling of damp coldness, and even lead to hypothermia and other risks. Furthermore, damp fabrics adhere to the skin, reducing the wearer's comfort. In recent years, the urgent need for fast-dampening and moisture-wicking materials has drawn attention to functional moisture-wicking fabrics.

[0003] Traditional and highly absorbent fabrics focus on improving the moisture absorption properties of materials; however, sweat is transported bidirectionally within these fabrics. As perspiration increases, sweat adheres to the skin surface under gravity. One-way moisture-wicking fabrics utilize thickness-direction wettability gradients or pore gradients to achieve unidirectional sweat wicking. However, the pores within the hydrophobic layer must simultaneously serve as sweat wicking channels and prevent backflow, making it difficult to simultaneously achieve excellent sweat wicking and backflow prevention properties. Therefore, developing novel fiber materials that can solve these problems is of great significance.

[0004] Sweat, as an important biofluid closely related to human health, contains various biomarkers such as electrolytes, metabolites, and proteins, providing a wealth of health information about physiological and metabolic states. For example, the concentration of chloride ions in sweat can serve as an indicator for assessing cystic fibrosis, pH levels can be used to determine metabolic alkalosis, and excessive calcium ion loss indicates a risk of hypocalcemia. Therefore, testing human sweat can monitor health status and provide early warnings for diseases. In light of this, there is an urgent need to develop novel functional fabrics that combine unidirectional sweat ionization with simultaneous detection of sweat biomarkers. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a sweat-mimicking nanofiber membrane and its application in unidirectional liquid-guiding fabrics.

[0006] The implementation process of this invention is as follows:

[0007] A method for preparing a sweat-mimicking nanofiber membrane includes the following steps: dispersing or dissolving a soluble hydrophobic polymer material and a micro / nano material in a solvent to obtain an electrospinning solution; using a spinning collection device with an array pore structure, electrospinning is performed using an electrospinning device to obtain a sweat-mimicking nanofiber membrane.

[0008] Furthermore, the soluble hydrophobic polymer material is selected from any one or a combination of several of poly(ε-caprolactone), polyurethane, polylactic acid, poly(ethylene lactide), polysulfone, polymethyl methacrylate, polyvinyl butyral, and polyvinylidene fluoride.

[0009] Furthermore, the micro / nano materials are selected from any one or a combination of several of the following: SiO2, zinc oxide, titanium oxide, attapulgite, halloysite, graphene oxide, hydroxyapatite, polystyrene, and polymethyl methacrylate.

[0010] Furthermore, the solvent is selected from any one or a combination of several of tetrahydrofuran, N,N-dimethylformamide, dichloromethane, chloroform, hexafluoroisopropanol, and ethanol.

[0011] Furthermore, the mass concentration of the soluble polymer material in the electrospinning solution is 0.1-5.0 g / ml; the electrospinning parameters are a voltage of 5 kV-20 kV, a flow rate of 0.1-2.0 ml / h, and a spinning distance of 5-20 cm.

[0012] Furthermore, the spinning collection device with an array of holes can be any one or a combination of several of the following: a spinning collection device with a circular hole array structure, a spinning collection device with a triangular hole array structure, a spinning collection device with a polygonal hole array structure, a spinning collection device with an irregular hole array structure, or a screen.

[0013] The sweat-inspired nanofiber membrane obtained by the above preparation method has sweat-guiding pores arranged in an array.

[0014] The above-mentioned application of the sweat-mimicking nanofiber membrane in fabrics, and the application of the sweat-mimicking nanofiber membrane in unidirectional liquid-guiding fabrics.

[0015] Furthermore, the sweat-mimicking nanofiber membrane is assembled with fabric to form a sweat-mimicking fabric; biomarkers in the sweat emanating from the nanofiber membrane are detected by adding an indicator to the sweat-mimicking fabric.

[0016] Furthermore, the indicator is a detection indicator that corresponds one-to-one with biomarkers in sweat.

[0017] The design concept of this invention:

[0018] Inspired by the sweat pore array of human skin, and drawing on the unidirectional sweat-guiding pattern of human sweat pores from the inside out, a sweat-mimicking nanofiber membrane is constructed. The sweat-mimicking pore array inside the nanofiber membrane is used to unidirectionally guide away large amounts of sweat, and the area around the sweat-mimicking pores is used to prevent the guided sweat from back seeping back. Furthermore, sweat component detection micro-areas are integrated into the sweat-mimicking pore nanofiber membrane, and based on colorimetry, multiple biomarkers in sweat can be intelligently detected by a smartphone.

[0019] The positive effects of this invention:

[0020] (1) Using electrospinning technology and a spinning collection device with an array pore structure, a controllable fabrication of a sweat-inspired nanofiber membrane was achieved. The sweat-inspired nanofiber membrane was assembled with a fabric to form a fabric with a wettability gradient. The effect of the sweat-inspired pore size on the transport performance of a single droplet was studied, and it was found that the droplet transport rate increases with the increase of pore size.

[0021] (2) This invention investigated the effect of pore spacing in the sweat-mimicking nanofiber membrane on the transport performance of large volumes of liquid. The results showed that as the pore spacing increased, the liquid transport rate decreased, and the residual area of ​​liquid on the hydrophobic side decreased. The liquid conduction rate of the sweat-mimicking fabric reached as high as 240 g·s. -1 ·m -2 The liquid residue area is only 16%, while that of nonwoven fabrics without an array of pores is only 25 g / s. -1 ·m -2 The liquid residue area of ​​the nonwoven fabric without an array of pores reached 100%. Furthermore, it was found that the anti-backflow performance of the liquid can be improved by increasing the hydrostatic pressure around the pores, and the hydrostatic pressure increases with the increase of the area around the pores. COMSOL was used to simulate the liquid dispersal process at and around the sweat-like pores, and the forces acting on the liquid in these two micro-regions were analyzed in detail, elucidating the mechanism by which the sweat-like pore fabric efficiently disperses liquid and prevents backflow.

[0022] (3) In the method of the present invention, micro and nano particles can improve the roughness and hydrophobicity of the biomimetic nanofiber membrane, thereby improving the one-way sweat-guiding speed and anti-backflow ability of the biomimetic nanofiber membrane.

[0023] (4) Application of the sweat-mimicking nanofiber membrane described in this invention in unidirectional liquid-guiding fabrics. This invention provides a new application direction for the sweat-mimicking nanofiber membrane for the simultaneous detection of biomarkers in sweat.

[0024] (5) Based on a sweat-mimicking nanofiber membrane, multiple sweat detection zones are constructed for the simultaneous detection of various biomarkers. This fabric can guide sweat to the detection zones through both unidirectional and lateral drainage, and the amount of sweat collected in each detection zone is controllable. Furthermore, different detection zones can be used to detect different biomarkers without interference between them. This fabric, integrating sweat drainage and detection functions, is expected to find applications in textiles, medicine, aesthetic medicine, sports medicine, aerospace, and other fields. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the array hole structure template used as a collection device in Example 5;

[0026] Figure 2 The structural control of the sweat-mimicking nanofiber membrane; (a) Schematic diagram of the preparation of the sweat-mimicking nanofiber membrane; (b) Macroscopic digital photograph of the sweat-mimicking nanofiber membrane; (c) SEM image of the sweat-mimicking nanofiber membrane; (c1, c2) Enlarged SEM images of the interior and surrounding areas of the sweat pores, respectively; (d) Statistical distribution of fiber diameter; (e) High-magnification SEM image of the sweat-mimicking nanofiber membrane; (f) Mapping image of the sweat-mimicking nanofiber membrane; (g) FTIR spectrum of the sweat-mimicking nanofiber membrane; (hj) Laser confocal microscopy (CLSM) images of sweat-mimicking nanofiber membranes with different structures; (i) Statistical analysis of fiber pore size and (j) water contact angle; (k) Image of water contact angle of the sweat-mimicking nanofiber membrane; (l) Image of air permeability.

[0027] Figure 3 To evaluate the wetting properties of nanofiber membranes with different SiO2 contents that mimic sweat pores; (a) photos of spinning solutions with different SiO2 contents; (b) low-magnification SEM images of three nanofiber membranes with different SiO2 contents; (c) high-magnification SEM images; (d) statistics of water contact angle; (e) wetting process of nanofiber membranes with different SiO2 loadings; and (f) statistics of wetting area changes over time.

[0028] Figure 4 The diagram shows the transport performance of large amounts of liquid for fabrics with different sweat-like pore structures and a control group of non-woven fabrics; (a) the liquid guiding process of fabrics with different pore spacings and non-woven fabrics in the control group; (b) statistics of the hydrophobic side contact area of ​​droplets before liquid guiding and the hydrophobic side dyeing area after liquid guiding; (c) the liquid guiding rate of fabrics with different structures and (d) the percentage of residual liquid area on the hydrophobic side to the liquid contact area.

[0029] Figure 5 The diagram shows the anti-backflow performance of the sweat-permeable fabric; (a) a photograph of liquid diffusion on the hydrophilic side of the sweat-permeable fabric; (b) a diagram of the hydrostatic pressure testing device; (c) a diagram showing the relationship between the area around the circular holes of the sweat-permeable fabric and the hydrostatic pressure; and (d) a linear fitting diagram showing the relationship between the area around the circular holes of the sweat-permeable fabric and the hydrostatic pressure.

[0030] Figure 6 Simulation diagrams to simulate the fluid transport process in the sweat-like pore fabric; (a1-a4) from the hydrophobic side to the hydrophilic side; (b1-b4) from the hydrophilic side to the hydrophobic side; velocity and pressure distribution curves of the fluid passing through the double-layer contact interface (c) from the hydrophobic side to the hydrophilic side (d) from the hydrophilic side to the hydrophobic side;

[0031] Figure 7 Schematic diagram of nanofiber fabric for sweat biomarker detection; (a) Schematic diagram of fabric preparation for sweat pore mimicry; (b) Digital photograph of the actual product; (c) Photograph of contact angles in different areas of the sweat pore mimicry fabric; (d) Photographs simulating the diffusion of sweat in cotton fabric and sweat detection micro-areas.

[0032] Figure 8 For colorimetric testing of biomarkers; (a) sweat markers (Cl - pH and Ca 2+ (a) Schematic diagram of colorimetric detection; (b) Cl - (c) pH, (d) Ca 2+ Colorimetric analysis of optical photographs and RGB analysis curves; (e.g.) R value, G value, B value and Cl - pH, Ca 2+ Linear fitting. Detailed Implementation

[0033] The present invention will be further described below with reference to the embodiments.

[0034] The novel functional fabric material, formed by combining the sweat-mimicking nanofiber membrane described in this invention with fabric, combines the unidirectional sweat evaporation function with the synchronous sweat detection function. This allows the wearer to keep their skin dry and comfortable during exercise, prevents sweat backflow, and simultaneously detects the components in the sweat. This invention will have important guiding significance for the development of the next generation of novel functional fabrics.

[0035] It should be noted that the ratio of soluble hydrophobic polymeric material to micro / nano materials in the method of this invention is not limited. In practical applications, those skilled in the art can choose any ratio as needed, as long as the obtained electrospinning solution can achieve electrospinning.

[0036] The ratio of soluble hydrophobic polymer to solvent in the method of this invention is not limited, as long as the mass concentration of soluble hydrophobic polymer in the electrospinning solution is 0.1-5.0 g / ml.

[0037] The type of solvent used in the method of this invention is not limited, as long as it can dissolve soluble hydrophobic polymer materials without dissolving micro- or nano-particles. Preferably, the method of this invention uses one or a combination of several of the following: tetrahydrofuran, N,N-dimethylformamide, dichloromethane, chloroform, hexafluoroisopropanol, and ethanol.

[0038] In the method of the present invention, the deposition time for electrospinning is not limited, and those skilled in the art can select the deposition time according to experimental needs.

[0039] The fabric used in the application of the method of the present invention is not limited. Those skilled in the art can choose different fabrics according to actual needs. Cotton fabrics are preferred in the method of the present invention.

[0040] The assembly described in this invention involves stacking biomimetic nanofiber membranes and fabrics. This invention does not impose many limitations on the assembly method; in practical applications, those skilled in the art can choose a suitable assembly method based on the situation and other factors. In this invention, a stitching method is preferred for assembly.

[0041] This invention relates to the application of the sweat-inspired nanofiber membrane in unidirectional liquid separation fabrics. The sweat-inspired nanofiber membrane is assembled with a fabric to form a sweat-inspired fabric; biomarkers in the sweat evaporated by the nanofiber membrane are detected by adding an indicator to the sweat-inspired fabric. The indicator used in this process can be diverse, and there is a one-to-one correspondence between the indicator and the target biomarker in the sweat, such as sodium ions, potassium ions, uric acid, chloride ions, pH, calcium ions, etc.

[0042] Example 1: Preparation method of sweat-pore-inspired nanofiber membrane

[0043] 0.13 g of hydrophobic SiO2 powder was added to a mixed solution of 1 mL tetrahydrofuran (THF) and 3 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 0.65 g of poly(ε-caprolactone) particles (PCL) were added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 7.4 kV, flow rate 0.5 mL / h, spinning distance 10 cm, and deposition time 12 min.

[0044] Comparative Example 1

[0045] The steps and methods are the same as in Example 1, except that hydrophobic SiO2 powder is not added.

[0046] Comparative Example 2

[0047] The steps and methods are the same as in Example 1, except that 0.26g of hydrophobic SiO2 powder is added.

[0048] Comparative Example 3

[0049] The steps and methods are the same as in Example 1, except that a spinning collection device without an array hole structure is used.

[0050] Example 2: Preparation method of sweat-pore-inspired nanofiber membrane

[0051] 0.13 g of hydrophobic SiO2 powder was weighed and added to a mixed solution of 1 mL tetrahydrofuran (THF) and 3 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 0.52 g of poly(ε-caprolactone) particles (PCL) were added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe and electrospun using an electrospinning device to obtain a sweat-inspired nanofiber membrane. The electrospinning parameters were as follows: voltage 7.4 kV, flow rate 0.5 mL / h, and spinning distance 10 cm. A spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.3-1.0 mm, 0.7-0.8 mm, and 0.7-1.2 mm, respectively, and the deposition time was 12 min, resulting in sweat-inspired nanofiber membranes with different pore sizes and pore spacings.

[0052] Example 3: Preparation method of sweat-pore-like nanofiber membrane

[0053] 0.13 g of hydrophobic SiO2 powder was weighed and added to a mixed solution of 1 mL tetrahydrofuran (THF) and 3 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 0.78 g of poly(ε-caprolactone) particles (PCL) were added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe and electrospun to obtain a sweat-inspired nanofiber membrane. The electrospinning parameters were as follows: voltage 7.4 kV, flow rate 0.5 mL / h, and spinning distance 10 cm. A spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.3-1.0 mm, 0.5-1.0 mm, 0.7-0.8 mm, 0.7-1.0 mm, and 0.7-1.2 mm, respectively, and the deposition time was 12 min, thus obtaining a series of sweat-inspired nanofiber membranes with different pore sizes and pore spacings.

[0054] Example 4: Imitation Sweat Pore Fabric

[0055] The sweat-inspired nanofiber membrane is assembled with cotton fabric, with the side in contact with the skin serving as the base, which is the sweat-inspired nanofiber membrane, and the side exposed to the air serving as the cotton fabric. The fabric is assembled by overlapping and sewing.

[0056] Example 5: Application of sweat-mimicking nanofiber membranes in liquid-unidirectional ionizing fabrics for detecting biomarkers.

[0057] Using the method and parameters described in Example 1, the collection device employs a metal plate with an aperture-pore spacing of 0.7-1.0 mm, constructing three sweat detection zones with a radius of 5 mm. Figure 1 As shown, a sweat-mimicking nanofiber membrane with a structure similar to that of the metal plate was obtained by depositing on the metal plate for 12 min. Cotton fabric was cut into three circular pieces with a radius of 5 mm using a punch. 15 μL of chloride ion indicator, 15 μL of pH universal indicator, and 10 μL of calcium ion indicator solution were dropped onto the surface of the three circular cotton fabrics respectively. After drying at room temperature for 10 min, the three circular cotton fabrics were placed in the sweat detection area on the sweat-mimicking nanofiber membrane to assemble the sweat biomarker detection nanofiber fabric.

[0058] The performance characterization and testing of Examples 1-5 are as follows:

[0059] 1. Characterization of sweat-mimicking nanofiber membranes

[0060] (1) Morphological characterization: The structure of the sweat-pore-like nanofiber membrane was observed using a laser confocal microscope (CLSM): 1% curcumin was added to the spinning solution as a fluorescent marker. The nanofiber membranes with different pore sizes and pore spacings were cut into 1cm×2cm pieces, laid flat on a glass slide, and sealed with a coverslip. The membranes were observed and images were captured at an excitation wavelength of 488nm.

[0061] The morphology of the fiber membrane was observed using scanning electron microscopy (SEM): The sweat-pore-like nanofiber membrane was cut into 1cm×1cm pieces, and the membrane was laid flat and fixed on the surface of a hollow plastic ring with a radius of 7mm and a height of 3mm using double-sided tape. The ring was then attached to conductive tape, sprayed with gold for 60 seconds, and observed using SEM. The diameter of 100 fibers was measured and the distribution pattern was statistically analyzed using Photoshop software. The pore size of 100 fibers was also measured and the distribution pattern was statistically analyzed.

[0062] (2) Composition characterization: The distribution of different elements on the sweat-mimicking nanofiber membrane was observed by mapping, and the chemical composition of the sweat-mimicking nanofiber membrane was analyzed by Fourier transform infrared spectroscopy (FTIR).

[0063] (3) Hydrophilicity and hydrophobicity test: The hydrophilicity and hydrophobicity of the sample were measured by a static contact angle meter (WCA). The change process of the contact angle of 2μL water on the sample surface was recorded. Five different positions on the sample were randomly selected for repeated testing. The average value was measured and recorded as the contact angle of the sample.

[0064] Experimental Results and Discussion:

[0065] By employing electrospinning technology combined with a customized template collection device, a sweat-mimicking nanofiber membrane with a sweat-mimicking pore array arrangement was obtained. Figure 2 a). Its macro digital photographs, such as Figure 2 As shown in b, the results indicate that the sweat-mimicking nanofiber membrane can be fabricated over a large area (25cm × 15cm). The morphology of the sweat-mimicking nanofiber membrane was observed using SEM, as shown below. Figure 2 As shown in Figure c, the prepared nanofiber membrane clearly exhibits a circular pore array structure similar to that of the collecting plate. Interestingly, the interior of the pores is not a through-hole structure, but rather contains a small amount of fiber deposition. The overall fiber distribution shows a characteristic of sparse fibers inside the pores and dense fibers around them. Figure 2 (c1-c2) This is because, during the electrospinning process, the difference in electric potential between the inside and around the holes of the circular hole array metal template leads to a difference in the electric field distribution. Nanofibers, positively charged by a high voltage, selectively deposit on the surface of the metal template around the holes, thus forming a nanofiber membrane with a morphology similar to the collecting template. Furthermore, statistical analysis shows that the fiber diameter in the fabricated sweat-pore-like nanofiber membrane is approximately 600 nm. Figure 2 d).

[0066] from Figure 2 As can be clearly seen, numerous nanoparticles are distributed on the surface of the sweat-mimicking nanofiber membrane. Mapping observation reveals that in addition to the C and O elements contained in PCL, Si elements are also clearly visible in the sweat-mimicking nanofiber membrane, and the Si elements are distributed along the fiber direction, proving that the nanoparticle composition is SiO2 (…). Figure 2 f). The composition of the fiber was analyzed using FTIR. Figure 2 As can be seen, nanofibers at 1729 cm⁻¹ -1 It exhibits a strong absorption band, attributed to the stretching vibration of C=O in PCL, while at 800 cm⁻¹... -1 and 470cm -1 The absorption bands correspond to the stretching vibration peaks of Si-O in SiO2, proving that SiO2 nanoparticles and PCL nanofibers were successfully combined.

[0067] Furthermore, by controlling the parameters of the circular pore array template, sweat-mimicking nanofiber membranes with pore diameter-pore spacing of 0.3-1.0, 0.5-1.0, 0.7-0.8, 0.7-1.0, and 0.7-1.2 mm were successively obtained. Curcumin was added to the spinning solution to stain the fiber membranes, and five different circular pore array structures could be clearly seen through CLSM images. Figure 2 h), enabling controllable fabrication of structures with different hole diameters and hole spacings. To investigate the influence of hole diameter and hole spacing on the fiber pore size inside the hole, statistical analysis of the fiber pore size inside the hole was conducted. Figure 2i) It was found that for the three groups of sweat-mimicking nanofiber membranes (0.3-1.0, 0.5-1.0, 0.7-1.0 μm), the internal fiber pore diameter of the circular pores increased from 1.8 μm to 2.7 μm with increasing pore size; for the three groups of sweat-mimicking nanofiber membranes (0.7-0.8, 0.7-1.0, 0.7-1.2 μm), the fiber pore diameter increased from 2.4 μm to 2.9 μm with increasing pore spacing. Furthermore, statistical analysis of the fiber pore diameter around the circular pores revealed that the fiber pore diameter remained relatively constant at around 0.7 μm, with minimal impact from changes in pore size. This indicates that the internal fiber pore diameter of the sweat-mimicking nanofiber membranes can be controlled by adjusting the pore size and pore spacing, providing a possibility for subsequent control and optimization of liquid transport performance.

[0068] The water contact angle of the sweat-mimicking nanofiber membrane was tested, and the water contact angles of different regions of the five types of sweat-mimicking nanofiber membranes were statistically analyzed. All five samples showed a contact angle at the pores that was slightly smaller than the contact angle around the pores. Figure 2 (jk). This is due to the structural difference between the low fiber deposition density at the pores and the high fiber deposition density around the pores. Simultaneously, as a sweat-wicking layer, the sweat-mimicking nanofiber membrane is required to have good breathability, such as... Figure 2 As shown in Figure 1, a sweat-mimicking nanofiber membrane is fixed in the middle of a pipe, and water is injected above the membrane to a certain height. It can be seen that the hydrophobicity of the sweat-mimicking nanofiber membrane prevents water from penetrating downwards. When airflow is introduced to the bottom of the pipe, a large number of bubbles appear in the water column above the fiber membrane, indicating that the sweat-mimicking nanofiber membrane has both hydrophobicity and air permeability.

[0069] In summary, a sweat-pore-inspired nanofiber membrane with a controllable array arrangement was successfully prepared by combining electrospinning technology with a template collection device. This fiber distribution structure with varying density inside and around the pores provides a possibility for balancing the liquid breakthrough pressure and anti-backflow performance during subsequent liquid transportation.

[0070] 2. Study on the wettability of sweat-mimicking nanofiber membranes

[0071] As a sweat-wicking layer that comes into close contact with the skin, it is crucial to prevent the material from becoming excessively wetted during the sweat-wicking process in order to maintain a dry and comfortable skin surface. This application investigates the effect of SiO2 composite content on the wettability of the sweat-mimicking nanofiber membrane by introducing hydrophobic vapor-phase SiO2 nanoparticles into PCL nanofibers.

[0072] Electrospun fibers were collected using templates ranging from 0.3 to 1.0 mm. By controlling the SiO2 composite ratio in the spinning solution, three groups of sweat-inspired nanofiber membranes were obtained: PCL, PCL / 20% SiO2 (mass percentage), and PCL / 40% SiO2 (mass percentage). Nonwoven fabric saturated with methylene blue aqueous solution was placed in a petri dish, and the three samples were spread evenly on the surface of the nonwoven fabric. After standing for 20 minutes, the wetting process of the methylene blue aqueous solution in the three membranes was recorded by video. ImageJ software was used to measure the wetted area and total sample area of ​​the three groups of samples at different time points. The percentage of wetted area to sample area was used to evaluate the effect of different SiO2 composite amounts on the wetting performance of the sweat-inspired nanofiber membranes.

[0073] Experimental Results and Discussion:

[0074] like Figure 3 As shown in Figure a, by controlling the SiO2 composite amount in the spinning solution, PCL, PCL / 20%SiO2, and PCL / 40%SiO2 spinning solutions were obtained sequentially. It can be seen that the PCL spinning solution is clear and transparent, gradually turning milky white with increasing SiO2 composite amount. SEM observation of the pseudo-pore nanofiber membranes with different SiO2 composite amounts shows that with increasing SiO2 composite amount, the fiber deposition density inside the pores increases, the patterning effect of the pseudo-pore nanofiber membranes prepared by electrospinning weakens, and it becomes almost impossible to observe the pore shape in the PCL / 40%SiO2 nanofiber membrane. Figure 3 (b) This may be because SiO2 itself is non-conductive. The addition of SiO2 reduces the conductivity of the spinning solution, decreasing the electric field force on the electrospun fibers. This weakens the dominant deposition effect of the fibers on the template, leading to a fiber distribution that tends towards a non-arrayed pore structure. High-magnification SEM observation of the fiber morphology of the three nanofiber membranes revealed that the PCL fibers without SiO2 had a smooth and flat surface; with increasing SiO2 composite content, more and more SiO2 nanoparticles were loaded on the fiber surface, making the fiber surface rougher. Figure 3 c).

[0075] The water contact angles of the three groups of nanofiber membranes were measured using a static contact angle meter. When the SiO2 composite content was 20% and 40%, the corresponding contact angles increased from 132° to 136°, both higher than the contact angle of the pure PCL fiber membrane (122°). Figure 3d). Further, the effect of SiO2 composite content on the wettability of the sweat-mimicking nanofiber membrane was investigated. The three membranes were laid flat on a nonwoven fabric saturated with methylene blue aqueous solution. It was observed that upon contact with the nonwoven fabric, the blue solution rapidly penetrated from the lower surface to the upper surface of the PCL membrane, with nearly 50% of the PCL membrane area being wetted, and the entire membrane was completely wetted within 6 seconds. However, the PCL / 20% SiO2 and PCL / 40% SiO2 membranes showed no blue dye penetration to the surface after 20 minutes. Figure 3 According to Wenzel's theory, surface microstructure can affect the wettability of materials; for hydrophobic surfaces, the rougher the structure, the more hydrophobic. In this invention, SiO2 nanoparticles are introduced into PCL to increase the surface roughness of the fibers, thereby successfully reducing the wettability of the nanofiber membrane.

[0076] In summary, when the SiO2 composite ratio is 20% by mass, the prepared nanofiber membrane has both a clear sweat-mimicking pore array structure and low wettability.

[0077] 3. Study on the one-way liquid guidance and anti-backflow performance of sweat-pore fabrics

[0078] A sweat-inspired nanofiber membrane with pore size-pore spacing of 0.3-1.0 mm, 0.5-1.0 mm, 0.7-0.8 mm, 0.7-1.0 mm, and 0.7-1.2 mm was assembled with cotton fabric to form a sweat-inspired fabric. A nonwoven fabric composed of a nanofiber membrane without array pore structure and cotton fabric was used as a control to study the liquid transport performance of sweat-inspired fabrics with different structures.

[0079] 3.1 Study on the effect of the spacing between the circular holes in the sweat-inducing fabric on the transport performance of large quantities of liquid

[0080] (1) Liquid transport rate test: Three groups of samples with pore size-pore spacing of 0.7-0.8, 0.7-1.0, and 0.7mm-1.2mm were taken, and a nanofiber fabric without array pore structure was used as the control group. The samples were cut to a fixed size according to the above method. 100μL (0.1g) of methylene blue aqueous solution was pipetted onto the hydrophobic side of the four tissues to simulate sweat, so that the liquid could cover the sweat pore structure of multiple sweat pore fabrics. The entire process of spontaneous transport of liquid to the hydrophilic layer was recorded by taking pictures with a mobile phone, and the entire liquid transport time T was recorded. At the same time, the area of ​​the hydrophobic layer covered by the liquid was measured by ImageJ software, and the average transport rate of transporting 100μL (0.1g) of liquid was calculated by formula (1).

[0081] V: V = 0.1 / S × T (1)

[0082] In the formula: S1 is the area of ​​the hydrophobic layer covered by the liquid (m²) 2T is the time (s) for transporting 100 μL (0.1 g) of liquid, and V is the average rate (g·s) for transporting 100 μL (0.1 g) of liquid. -1 ·m -2 Each group of samples was measured three times and the average value was taken.

[0083] (2) Residual Moisture Area Test: Based on the above experiments, the residual area S of blue dye in the four groups of samples after liquid transportation was measured using ImageJ software. 2， Calculate the percentage of blue area S using formula (2). w :

[0084] S w =S2 / S1×100% (2)

[0085] In the formula: S1 is the area of ​​the hydrophobic layer covered by the liquid (m²) 2 S2 is the area of ​​the blue dye (m²) 2 ), S w The percentage of blue area is %. Each group of samples was measured three times and the average value was taken.

[0086] The impact of different fabric structures on the performance of transporting large volumes of liquids is evaluated by combining the liquid transport rate and the residual moisture area after transport.

[0087] Experimental Results and Discussion:

[0088] To investigate the transport performance of sweat-inspired fabrics for large volumes of liquid, based on the above experimental results, three groups of sweat-inspired fabrics with a pore diameter of 0.7 mm and a pore spacing of 0.8, 1.0, and 1.2 mm were used to study the effect of the pore spacing on the transport performance of large volumes of liquid, with nonwoven fabrics as a control. Figure 4 This study demonstrates the transport process of 100 μL of liquid in fabrics with different structures. First, observing the liquid transport in the sweat-inspired fabric reveals that the liquid initially covers an array of circular holes. Over time, the liquid tends to converge from around the holes towards the holes themselves, eventually penetrating vertically into the hydrophilic layer. Recording the liquid transport time for the three sweat-inspired fabrics shows that as the hole spacing increases from 0.8 mm to 1.2 mm, the liquid transport time increases from 3 s to 10 s, attributed to a decrease in the number of circular holes. In contrast, observing the liquid transport in the control group nonwoven fabric, liquid transport only begins at 23 s, and the entire liquid transport process takes 25 s. Measuring the average liquid transport rate (…) Figure 4 c) It can be observed that as the spacing between the circular holes in the sweat-like fabric increases from 0.8 and 1.0 mm to 1.2 mm, the liquid transport rate decreases sequentially from 240 and 150 g·s⁻¹ to 91 g·s⁻¹. -1 ·m -2However, the liquid transport rate of all three groups of sweat-mimicking fabrics was greater than that of nonwoven fabrics (25 g·s⁻¹). -1 ·m -2 This is because the hydrophobic layer of nonwoven fabric is made up of densely packed fibers. Compared to sweat-like fabrics, it does not have dedicated liquid transport channels. The tightly packed fibers form small fiber pores, which means that the resistance to liquid transport is increased, resulting in a longer time for liquid to penetrate.

[0089] To characterize the residual moisture in the hydrophobic layer during liquid transport, the transported liquid was dyed with methylene blue. It was clearly observed that the residual blue dye area on the hydrophobic side varied significantly among fabrics with different structures after the liquid transport process. Figure 4 (ab). As the spacing between the circular holes in the three sets of sweat-inducing fabrics increases, the proportion of blue area decreases. When the hole spacing is 0.8 mm, the blue area accounts for nearly 40% of the liquid coverage area, while when the hole spacing is 1.0 mm and 1.2 mm, the blue area is 16% and 12% respectively. Figure 4 d) Furthermore, the blue markings are distributed in a circular hole array: the color is darker at the holes, and almost no color residue remains around the holes, proving that the circular hole array structure acts as a channel for liquid transport. While the liquid did not diffuse on the surface of the control group nonwoven fabric, the blue dye residue area was close to 100% after liquid transport. The results indicate that the sweat-mimicking pore structure design effectively reduces moisture residue on the hydrophobic side during liquid transport compared to the non-arrayed pore structure, and the residue area decreases with increasing hole spacing, demonstrating high liquid transport efficiency. This is because during liquid transport, all fiber pores in the nonwoven fabric that come into contact with the liquid act as liquid-guiding channels. After liquid guidance, liquid residue inevitably remains between the fiber pores, and the residue area increases with the increase of liquid-guiding channels. In contrast, the sweat-mimicking pore fabric has dedicated liquid-guiding channels on the hydrophobic side, and the number of channels decreases with increasing hole spacing. Therefore, compared to nonwoven fabric, it reduces moisture residue in the hydrophobic layer and improves liquid transport efficiency.

[0090] In summary, when the hole spacing increases from 0.8 mm to 1.0 mm, although the liquid transport rate decreases by 37.5%, the area of ​​residual moisture decreases by nearly 60%. Therefore, considering both the liquid transport rate and the residual moisture after transport, the hole array structure with a hole diameter of 0.7 mm and a hole spacing of 1.0 mm is selected as having the best liquid transport performance, demonstrating the potential of sweat-mimicking fabrics in sweat transport.

[0091] 3.2 Study on the anti-backflow performance of sweat-pore fabrics

[0092] (1) A self-made hydrostatic pressure testing device was used to study the anti-backflow performance of the sweat-like pore fabric: The bottom of two plastic injection needles was removed, and the tops were joined together. Three groups of sweat-like pore fabrics with different pore spacings of 0.7-0.8, 0.7-1.0, and 0.7mm-1.2mm were placed with the hydrophilic side facing up at the joining point and fixed with a clamp. Methylene blue aqueous solution was slowly added to the hydrophilic side of the syringe. The height h at which the liquid just broke through the critical liquid level of the sweat-like pore fabric was recorded. The hydrostatic pressure p corresponding to each group of samples was calculated according to formula (3):

[0093] p=ρ·g·h (3)

[0094] In the formula: ρ is the solution density (1 kg / m³). 3 ), g is the acceleration due to gravity (9.8 N / kg), h is the height of the liquid surface (m), each group of experiments was conducted three times, and the average value was calculated.

[0095] (2) Calculation of the area ratio of the region surrounding the circular hole:

[0096] S A =(D 2 -πr 2 ) / D 2 ×100% (4)

[0097] In the formula, D is the hole spacing (mm) and r is the hole radius (mm).

[0098] Experimental Results and Discussion:

[0099] To demonstrate the contribution of the area surrounding the circular holes to the anti-backflow performance of the liquid, three groups of sweat-inspired pore fabrics with structures of 0.7-0.8, 0.7-1.0, and 0.7-1.2 were used to study the effect of different pore spacings on the anti-backflow performance. First, 100 μL of methylene blue aqueous solution was dropped onto the hydrophilic side of the sweat-inspired pore fabric; the blue liquid rapidly diffused on the hydrophilic surface. Figure 5 a) and the diffusion area increases over time; simultaneously, using Figure 5 The homemade hydrostatic pressure testing device shown in b, with the sweat-like pore fabric fixed in the middle, allows for the continuous and slow dripping of liquid onto the hydrophilic side. A tall water column is clearly visible on the hydrophilic side of the fabric, and at a certain liquid level, the liquid does not penetrate the hydrophobic layer, demonstrating the anti-backflow performance of the sweat-like pore fabric. The magnitude of the hydrostatic pressure is used to evaluate the effect of different pore spacings on the anti-backflow performance of the sweat-like pore fabric. Figure 5c) The results showed that as the spacing between the circular holes increased from 0.8, 1.0, to 1.2 mm, the corresponding area ratios around the holes were 40%, 61.5%, and 73.3%, respectively, and the hydrostatic pressure that the sweat-permeable fabric could withstand increased from 310 and 370 Pa to 410 Pa. By fitting the area ratio around the holes of the three groups of sweat-permeable fabrics with the magnitude of the hydrostatic pressure, a good linear relationship was found between the two, R0. 2 =0.9879 ( Figure 5 d).

[0100] This is because: if the sweat-inspired fabric is simplified into a series of vertically and parallelly arranged cylindrical nanopores, this phenomenon can be explained by the Laplace equation. When the liquid passes through the hydrophilic layer and reaches the hydrophobic biomimetic fiber membrane interface, it will be subjected to hydrophobic capillary force p provided by the nanopores of the hydrophobic layer. i This will prevent the liquid from penetrating further through the hydrophobic layer. The hydrostatic pressure p can be understood as the sum of the Laplace pressures generated by a single hydrophobic nanopore, according to the Laplace equation:

[0101]

[0102] In the formula: γ is the surface tension of the fluid, θ i It is the water contact angle at the hydrophobic nanofiber interface, R i This is the radius of the i-th nanopore. As the nanopore size decreases, the hydrophobic capillary force generated by a single pore increases. Since the pore size of the fibers around the circular pores of the sweat-mimicking nanofiber membrane is much smaller than that inside the circular pores, the hydrostatic pressure of the sweat-mimicking fabric is mainly provided by the area around the circular pores, and increases with the increase of the spacing between the circular pores. This explains the linear relationship between the area around the circular pores and the hydrostatic pressure. However, the intercept of the fitted line is not zero because the fibers inside the circular pores also provide a small portion of the hydrostatic pressure. It should be noted that under actual conditions, sweat transported to the hydrophilic layer will immediately diffuse within the hydrophilic layer without forming a high liquid level. Therefore, the above results indicate that all three groups of sweat-mimicking fabrics can effectively prevent sweat backflow.

[0103] In summary, when liquid is transported from the hydrophilic side to the hydrophobic side in the sweat-inspired fabric, the hydrophobic side with the biomimetic structure mainly uses the area around the pores to hinder further liquid transport. Furthermore, it has been demonstrated that the anti-backflow performance increases with the increase of the pore spacing, which is consistent with the design strategy presented in this paper.

[0104] 3.3 Mechanism of one-way liquid guidance and anti-sweat backflow of sweat-mimicking fabric

[0105] The volume distribution of fluid in the sweat-permeable fabric was simulated using COMSOL software, and the fluid conduction mechanism of the fabric was explained by combining force analysis. Figure 6As shown in diagram ab, each small circle represents an assembly of hydrophobic fibers with a thickness of 50 μm, and the large circle represents an assembly of hydrophilic fibers with a thickness of 80 μm. When a liquid is transported within the fiber membrane, it is subjected to capillary forces, the magnitude of which can be calculated using the Laplace equation:

[0106] P=4γcosθ / d (6)

[0107] In the formula: γ is the surface tension of the liquid, θ is the contact angle of the liquid on the fiber membrane, and d represents the pore size between the fibers of the fiber membrane. When the liquid is transported in the hydrophobic membrane, since the contact angle θ > 0 and cosθ < 0, the capillary force on the liquid is negative, denoted as the hydrophobic capillary force P. S θ is used to describe the repulsive force on a liquid; when a liquid is transported in a hydrophilic membrane, θ < 0. Similarly, substituting into the above equation, the capillary force is positive, indicating that the liquid is subjected to a hydrophilic capillary force P in the same direction as the transport. C .

[0108] When the liquid comes into contact with the hydrophobic layer ( Figure 6 a1), the liquid is subjected to gravity P G and hydrophobic capillary force P S Because the pore size of the fibers at the circular holes in the hydrophobic layer is much smaller than that in the surrounding area, the liquid experiences lower intrusion pressure at the circular holes, making it more likely to penetrate the hydrophobic layer through them. When the liquid passes through the hydrophobic layer and comes into contact with the hydrophilic layer ( Figure 6 a2), hydrophilic capillary force direction P C In the same direction as liquid transport, at P C Under the influence of the double membrane, the transport speed of the liquid in the double membrane increases. When the liquid continues to transport in the double membrane ( Figure 6 a3), the liquid in P C With P S Under the combined effect of these factors, the transport speed is further accelerated; this phenomenon is also known as the "push-pull effect." When the liquid is completely transported to the hydrophilic layer ( Figure 6 a4), subjected to P from all directions of the hydrophilic layer C And downward P S The liquid diffuses and remains in a steady state within the hydrophilic layer. When the liquid transports from the hydrophilic side to the hydrophobic side, it does so within the P layer. C Under this action, the liquid only diffuses in the hydrophilic layer. Figure 6 b1-b3), when the liquid comes into contact with the hydrophobic layer ( Figure 6 b4), subject to upward P S and P C The combined force moves upwards, ultimately overcoming gravity P. G The fabric remains stable in the hydrophilic layer and cannot penetrate further downwards. The above analysis clarifies the one-way liquid guiding principle of the sweat-mimicking fabric, and the simulation results are consistent with the experimental results.

[0109] To perform qualitative and quantitative analysis of fluid distribution, the liquid velocity and pressure at the hydrophobic-hydrophilic interface were calculated, such as... Figure 6 As shown in Figure c, when the liquid passes through the hydrophobic layer to reach the hydrophilic layer, the liquid flow rate significantly increases under a negative pressure close to -600 Pa, and the negative pressure region is located at the circular hole (region 1), further verifying that the circular hole acts as a channel for liquid transport during the conduction process. Simultaneously, when the liquid moves from the hydrophilic layer to the hydrophobic layer, it experiences positive pressure at the interface, hindering the downward transport of the liquid. Furthermore, due to… Figure 6 As can be observed, the pressure around the orifice (regions 2 and 3) is close to 300 Pa, which is much higher than the pressure in the middle region, indicating that the region around the orifice plays a major role in preventing the reverse transport of liquid.

[0110] 4. Preparation and assembly of biomarker detection micro-regions in sweat-mimicking nanofiber fabrics

[0111] PCL / SiO2 nanofiber membranes were obtained by collecting electrospun fibers using electrospinning technology combined with a customized template. These membranes retained a sweat-mimicking pore array structure, and three sweat detection areas were pre-defined on this structure. Figure 7 b. For example Figure 7 As shown in Figure a, a sweat biomarker detection nanofiber fabric is formed by assembling it with cotton fabric loaded with three indicators, thus enabling the detection of sweat biomarkers. Figure 7 As shown in Figure c, cotton fabric exhibits superhydrophilicity in terms of wettability, with a contact angle of approximately 0°. In contrast, the PCL / SiO2 nanofiber membrane bonded to it exhibits hydrophobicity with a contact angle of approximately 130°, which is attributed to the combined effect of hydrophobic PCL and hydrophobic SiO2 nanoparticles.

[0112] To enable the simultaneous detection of three sweat components, the sweat biomarker detection nanofiber fabric must be able to effectively manage the collected sweat in separate zones to prevent interference between sweat and indicators, thus ensuring that the indicator color does not cross-color during the detection process. Figure 7 d demonstrates the sweat management performance of the sweat biomarker detection nanofiber fabric, with cotton fabric discs placed on top as a control. Methylene blue aqueous solution was used to simulate sweat, and continuously dripped onto the sweat detection area of ​​the sweat biomarker detection nanofiber fabric. It was observed that sweat spread rapidly on the latter's surface, and the diffusion area gradually increased with increasing drip volume. The former, however, exhibited excellent sweat management performance; when the sweat volume increased from 10 μL to 70 μL, the liquid remained firmly concentrated in the sweat detection area, forming an increasingly higher liquid surface without spreading outwards.

[0113] 5. Detection of sweat biomarkers: Colorimetric detection of different chloride ions, pH, and calcium ions in nanofiber fabrics.

[0114] Chloride ion colorimetric detection: NaCl solutions with chloride ion concentrations of 0, 20, 40, 60, 80, and 100 mM were prepared sequentially. 20 μL of each NaCl solution was pipetted onto a cotton fabric disc loaded with a chloride ion indicator. After reacting for 2 minutes, a color image was captured using a mobile phone (Huawei nova 7). The color change was then quantitatively analyzed using the "Color Recognition" application (available for download in the Android app store) to provide the RGB values ​​of the target area. To minimize the impact of ambient light on the color results, the entire shooting process was conducted under 40W LED lighting, with a uniform blue cardstock as the background. The shooting distance was fixed at 20 cm, and three measurements were taken for each group, with the average value recorded.

[0115] pH colorimetric detection: Similar to the colorimetric detection of calcium ions and chloride ions, the pH detection range is 4, 5, 6, 7, 8;

[0116] Calcium ion colorimetric detection: Prepare CaCl2 solutions with concentration ranges of 0, 2, 4, 6, 10, and 15 mM, respectively. The remaining detection steps are the same as described above. Each group is measured three times, and the average value is taken. All experiments are conducted at room temperature (25℃).

[0117] Experimental Results and Discussion:

[0118] Smartphones can analyze and record captured images using mobile software, converting color changes in nanofiber fabrics containing sweat biomarkers into semi-quantitative data. Therefore, by establishing correlations between the data and the concentrations of relevant biomarkers, the concentration information of each component in the sweat can be obtained. In this study, three biomarkers in sweat, Cl... - pH and Ca 2+ Conduct testing. Figure 8 a is a schematic diagram of the detection of different components. For Cl - Detection shows that Cl - As the concentration increases from 0, 20, 40, 60, 80 to 100 mM, the indicator color changes from colorless to yellow, and the color (yellow) gradually deepens. Figure 8 b) Its RGB percentage curve shows that as Cl - With increasing concentration, the proportion of R values ​​increased from 32.7% to 43%, the proportion of G values ​​remained relatively stable at around 34%, and the proportion of B values ​​decreased from 33% to 22%. The R, G, and B values ​​were then compared with Cl... - Linear fitting of concentration revealed that the R-value correlated with Cl. - There was a good linear correlation in the concentration range of 5 mM-100 mM, R 2 =0.9650 ( Figure 8e). For pH detection, within the physiologically relevant range (pH 4-8), the indicator color tends to gradually change from dark red to green. Figure 8 c) The RGB percentage curves show that the R value decreased from 44.1% to 39.1%, the G value increased from 29.2% to 33.7%, and the B value remained relatively stable around 27%. Linear fitting of the R, G, and B values ​​with pH showed a good linear correlation between the G value change and pH. 2 =0.9986 ( Figure 8 f). With Ca 2+ When the concentration increased from 0, 2, 4, 6, 10 to 15 mM, the indicator color changed from light purple to dark purple. Figure 8 d) According to the RGB value conversion, the R value ratio remained around 31%, the G value decreased from 30.5% to 26.3%, and the B value increased from 38.7% to 42.2%. The R, G, and B values ​​were then compared with Ca... 2+ Linear fitting of concentration revealed that the B value was related to Ca. 2+ The concentration showed a good linear correlation, R 2 =0.9829( Figure 8 g).

[0119] Example 6: Preparation method of sweat-pore-like nanofiber membrane

[0120] 0.4 g of zinc oxide powder was weighed and added to a mixed solution of 2 mL tetrahydrofuran (THF) and 2 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 7.2 g of polyurethane (PU) was added to the dispersion and stirred at room temperature for 15 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 5 kV, flow rate 0.1 mL / h, spinning distance 5 cm, and deposition time 20 min.

[0121] Example 7: Preparation method of sweat-pore-like nanofiber membrane

[0122] 0.13 g of hydrophobic SiO2 powder was weighed and added to a mixed solution of 3 mL tetrahydrofuran (THF) and 1 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 2 h, 1.2 g of polyurethane (PU) was added to the dispersion and stirred at room temperature for 15 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 20 kV, flow rate 2.0 mL / h, spinning distance 15 cm, and deposition time 20 min.

[0123] Example 8: Preparation method of sweat-pore-inspired nanofiber membrane

[0124] 0.3 g of titanium dioxide powder was weighed and added to a mixed solution of 2 mL of tetrahydrofuran (THF) and 2 mL of N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 4 g of polylactic acid (PLA) was added to the dispersion and stirred at room temperature for 15 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 20 cm, and deposition time 15 min.

[0125] Example 9: Preparation method of sweat-pore-like nanofiber membrane

[0126] 0.23 g of attapulgite powder was weighed and added to a mixed solution of 3 mL tetrahydrofuran (THF) and 1 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 0.4 g of polylactic acid (PLA) was added to the dispersion and stirred at room temperature for 15 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0127] Example 10: Preparation method of sweat-pore-like nanofiber membrane

[0128] 0.3 g of attapulgite powder was added to 4 mL of tetrahydrofuran (THF) and ultrasonically dispersed for 3 h. Then, 5.6 g of poly(lactic-co-glycolic acid) (PLGA) was added to the dispersion and stirred at room temperature for 15 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0129] Example 11: Preparation method of sweat-pore-inspired nanofiber membrane

[0130] 0.5 g of halloysite powder was weighed and added to a mixed solution of 3 mL of tetrahydrofuran (THF) and 1 mL of N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1 h, 0.8 g of poly(lactic-co-glycolic acid) (PLGA) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0131] Example 12: Preparation method of sweat-pore-like nanofiber membrane

[0132] 2g of graphene oxide powder was weighed and added to 4mL of N,N-dimethylformamide (DMF). After ultrasonic dispersion for 1h, 6g of polysulfone (PSF) was added to the dispersion and stirred at room temperature for 12h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of circular pores was used. The pore size-pore spacing parameters of the metal plate were 0.7-1.0mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15kV, flow rate 0.8mL / h, spinning distance 15cm, and deposition time 15min.

[0133] Example 13: Preparation method of sweat-pore-inspired nanofiber membrane

[0134] 1 g of hydroxyapatite powder was weighed and added to a mixed solution of 1 mL hexafluoroisopropanol and 3 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 2 h, 0.8 g of polysulfone (PSF) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of triangular pores was used. The pore spacing of the metal plate was 1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0135] Example 14: Preparation method of sweat-pore-inspired nanofiber membrane

[0136] 1 g of titanium dioxide powder was weighed and added to a mixed solution of 1 mL tetrahydrofuran (THF) and 3 mL chloroform. After ultrasonic dispersion for 2 h, 0.4 g of polymethyl methacrylate (PMMA) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of hexagonal pores was used. The pore spacing of the metal plate was 1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0137] Example 15: Preparation method of sweat-pore-like nanofiber membrane

[0138] 4g of halloysite powder was weighed and added to a mixed solution of 1mL dichloromethane and 3mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 2 hours, 7.2g of polymethyl methacrylate (PMMA) was added to the dispersion and stirred at room temperature for 12 hours until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of rectangular pores was used. The pore spacing of the metal plate was 1.0mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15kV, flow rate 0.8mL / h, spinning distance 15cm, and deposition time 15min.

[0139] Example 16: Preparation method of sweat-pore-inspired nanofiber membrane

[0140] 1 g of polystyrene powder was weighed and added to 4 mL of ethanol. After ultrasonic dispersion for 2 h, 2.4 g of polyvinyl butyral (PVB) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe, and a sweat-mimicking nanofiber membrane was obtained by electrospinning using a spinning collection device with an array of triangular pores and a pore spacing parameter of 1.0 mm on the metal plate. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0141] Example 17: Preparation method of sweat-pore-like nanofiber membrane

[0142] 1 g of polymethyl methacrylate was weighed and added to 4 mL of ethanol. After ultrasonic dispersion for 2 h, 0.4 g of polyvinyl butyral (PVB) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe, and a spinning collection device with an array of square pores was used. The pore spacing of the metal plate was 1.0 mm. A sweat-mimicking nanofiber membrane was obtained by electrospinning using an electrospinning device. The electrospinning parameters were as follows: voltage 15 kV, flow rate 0.8 mL / h, spinning distance 15 cm, and deposition time 15 min.

[0143] Example 18: Preparation method of sweat-mimicking nanofiber membrane

[0144] 0.8 g of hydrophobic SiO2 powder was weighed and added to a mixed solution of 1 mL tetrahydrofuran (THF) and 3 mL N,N-dimethylformamide (DMF). After ultrasonic dispersion for 4 h, 3.6 g of polyvinylidene fluoride (PVDF) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe and electrospun to obtain a sweat-mimicking nanofiber membrane. The electrospinning parameters were as follows: voltage 10 kV, flow rate 1.5 mL / h, and spinning distance 15 cm. A spinning collection device with an array of irregular pores was used, the pore spacing of the metal plate was 1.0 mm, and the deposition time was 12 min.

[0145] Example 19: Preparation method of sweat-pore-inspired nanofiber membrane

[0146] 0.8 g of hydrophobic SiO2 powder was added to 4 mL of N,N-dimethylformamide (DMF) and ultrasonically dispersed for 4 h. Then, 0.8 g of polyvinylidene fluoride (PVDF) was added to the dispersion and stirred at room temperature for 12 h until completely dissolved. The solution was transferred to a glass syringe and electrospun to obtain a sweat-mimicking nanofiber membrane. The electrospinning parameters were as follows: voltage 7.4 kV, flow rate 0.5 mL / h, and spinning distance 10 cm. A sieve with an array of pores was used as the spinning collection device, with a pore spacing of 1.0 mm and a deposition time of 12 min.

[0147] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a sweat-pore-inspired nanofiber membrane, characterized in that, The process includes the following steps: dispersing or dissolving soluble hydrophobic polymer materials and micro / nano materials in a solvent to obtain an electrospinning solution; using a metal spinning collection device with an array of pores, electrospinning is performed using an electrospinning device. During the electrospinning process, the difference in conductivity between the inside and around the pores of the spinning collection device causes fibers to deposit densely around the pores to form small pores and sparsely inside the pores to form large pores, thereby obtaining a sweat-inspired nanofiber membrane with a gradient pore size structure of sparse fibers inside the pores and dense fibers around the pores. The sweat-inspired nanofiber membrane is a hydrophobic fiber membrane. The liquid conductivity of the sweat-mimicking nanofiber membrane can reach 240 g·s. -1 ·m -2 The liquid residue area was only 16%; The soluble hydrophobic polymer material is selected from any one or a combination of poly(ε-caprolactone), polyurethane, polylactic acid, poly(ethylene lactide), polysulfone, polymethyl methacrylate, polyvinyl butyral, and polyvinylidene fluoride; the metal spinning collection device with an array pore structure has a pore size of 0.3~0.7 mm and a pore spacing of 1.0~1.2 mm; the large pores serve as liquid flow channels, and the dense fiber region around the small pores prevents liquid backflow; the pore size of the large pores is 1.8~2.7 μm, and the pore size of the small pores is 0.7 μm; The mass concentration of soluble polymer material in the electrospinning solution is 0.1-5.0 g / ml; the electrospinning parameters are a voltage of 5 kV-20 kV, a flow rate of 0.1-2.0 ml / h, and a spinning distance of 5-20 cm.

2. The preparation method according to claim 1, characterized in that: The micro- and nanomaterials are selected from any one or a combination of several of the following: SiO2, zinc oxide, titanium oxide, attapulgite, halloysite, graphene oxide, hydroxyapatite, polystyrene, and polymethyl methacrylate.

3. The preparation method according to claim 1, characterized in that: The solvent is selected from any one or a combination of several of tetrahydrofuran, N,N-dimethylformamide, dichloromethane, chloroform, hexafluoroisopropanol, and ethanol.

4. The preparation method according to claim 1, characterized in that: The spinning collection device with an array of holes can be any one or a combination of several of the following: a spinning collection device with a circular hole array structure, a spinning collection device with a polygonal hole array structure, a spinning collection device with an irregular hole array structure, or a screen.

5. The sweat-pore-like nanofiber membrane obtained by the preparation method according to claim 1, characterized in that: The sweat-mimicking nanofiber membrane has both macropore and micropore structures. The macropores serve as liquid flow channels, while the micropores prevent liquid backflow. The macropore diameter is 1.8~2.7 μm, and the micropore diameter is 0.7 μm.

6. The application of the sweat-mimicking nanofiber membrane according to claim 5 in fabrics, characterized in that: Application of the sweat-mimicking nanofiber membrane in unidirectional liquid-guiding fabrics.

7. The application according to claim 6, characterized in that: A sweat-inspired nanofiber membrane is assembled with a fabric to form a sweat-inspired fabric, wherein the hydrophilic fabric side of the sweat-inspired fabric serves as a sweat detection area; biomarkers in the sweat emanating from the nanofiber membrane are detected by adding an indicator to the sweat-inspired fabric.

8. The application according to claim 7, characterized in that: The indicator is a detection indicator that corresponds one-to-one with biomarkers in sweat.

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