Multifunctional conductive composite fiber membrane with Janus structure and preparation method of multifunctional conductive composite fiber membrane
By preparing a multifunctional conductive composite fiber membrane with a Janus structure and combining it with electrospinning and in-situ polymerization of conductive fillers, the problem of improving the strain sensing and photothermal performance of the conductive composite fiber membrane was solved, achieving wide-range strain sensing, high sensitivity and excellent photothermal performance, which is suitable for wearable electronics and smart medical care.
Patent Information
- Application Number
- CN202511125873.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-10-10
AI Technical Summary
There is room for improvement in the strain sensing and photothermal performance of existing conductive composite fiber membranes, especially the difficulties in multifunctional integration, and the creep and hysteresis properties of polymer materials limit their performance improvements.
A multifunctional conductive composite fiber membrane with a Janus structure is used to prepare an asymmetric structure of nanofiber and micron fiber layers by electrospinning, combined with plasma treatment and in-situ polymerization of ultrasonic conductive fillers to form a conductive network, thereby enhancing the strain sensing performance and photothermal performance.
It achieves a wide strain sensing response range, high sensitivity and good cycle stability, and has excellent photothermal conversion capabilities, making it suitable for wearable electronics and smart medical fields.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of conductive polymer composite materials, and particularly relates to a multifunctional conductive composite fiber membrane with a Janus structure and a preparation method thereof. Background Art
[0002] With the rapid development of fields like automation, artificial intelligence, and healthcare, flexible electronic materials are garnering increasing attention. In particular, stretchable conductive composite fiber membranes offer strain sensing capabilities, combining wearability, lightweight construction, and high sensitivity, making them suitable for applications in robotics, human-computer interaction, and health monitoring. Furthermore, the preparation of conductive composite fiber membranes using polymer processing techniques such as electrospinning offers simplicity, low cost, and excellent reproducibility, making them suitable for mass production.
[0003] As a strain sensor, the conductive composite fiber membrane should have a wide sensing range, high sensitivity and stable signal response. However, the creep, hysteresis and other characteristics of polymer materials limit the improvement of the performance of the conductive composite fiber membrane. The continuous improvement of science and technology and living standards has put forward higher requirements on the performance of the conductive composite fiber membrane, and the application scenarios have become more complex and diversified, which has also prompted the conductive composite fiber membrane to develop towards multifunctionality. For example, in the medical field, if it has both strain sensing and photothermal functions, photothermal therapy can be implemented simultaneously after detection to relieve symptoms. At present, the preparation of multifunctional integrated conductive composite fiber membranes through simple processes still requires further exploration and research. Summary of the Invention
[0004] The purpose of the present invention is to provide a multifunctional conductive composite fiber membrane with a Janus structure, wherein the composite fiber membrane has high strain sensing performance and excellent light-to-heat conversion capability.
[0005] The technical solution adopted in the present invention is as follows:
[0006] A multifunctional conductive composite fiber membrane with a Janus structure is obtained by the following preparation method, comprising the following steps:
[0007] 1) Preparation of Janus structure electrospun fiber membrane consisting of nanofiber layer and microfiber layer;
[0008] 2) Plasma treatment of Janus structure electrospun fiber membrane;
[0009] 3) The treated Janus structure electrospun fiber membrane is ultrasonically treated and subjected to in-situ polymerization of conductive fillers to form a conductive network to obtain the multifunctional conductive composite fiber membrane.
[0010] Preferably, in step 1), the electrospun fiber membrane is received by a roller wrapped with aluminum foil, and the micron fiber layer is spun first and then the nanofiber layer is spun to obtain an asymmetric fiber membrane structure, namely a Janus structure.
[0011] The nanofiber layer and micron fiber layer are obtained by electrospinning low-concentration and high-concentration spinning solutions respectively. The mass concentration of the low-concentration spinning solution is 10-12%, preferably 12%; the mass concentration of the high-concentration spinning solution is 20-24%, preferably 24%.
[0012] The spinning solution is a polymer solution obtained by dissolving polymer pellets in an organic solvent. Different concentrations can be achieved by adjusting the amount of polymer pellets used. Preferably, the polymer pellets are thermoplastic polyurethane (TPU), and the organic solvent is a mixture of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) in a 1:1 volume ratio. In other words, the spinning solution is obtained by dissolving TPU in a mixture of equal volumes of DMF and THF.
[0013] Furthermore, the plasma treatment in step 2) is O2 plasma treatment, and the treatment time is 1-3 minutes, preferably 2 minutes.
[0014] In step 3), the fiber membrane is immersed in a dispersion of the first conductive filler and treated with ultrasound.
[0015] The first conductive filler is one of carbon black (CB), graphene, reduced graphene oxide, carbon nanotubes, and MXene. The dispersion medium is anhydrous ethanol. The concentration of the first conductive filler is 5-15 mg / mL.
[0016] The ultrasonic power is 70W and the ultrasonic time is 3-15min.
[0017] More preferably, the concentration of the first conductive filler dispersion is 10 mg / mL, and the ultrasonic treatment time is 9 minutes.
[0018] Furthermore, the electrospun fiber membrane after ultrasonic treatment is immersed in a second conductive filler solution to carry out an in-situ polymerization reaction, wherein the second conductive filler is pyrrole and a catalyst is added to the solution.
[0019] Preferably, the concentration of the pyrrole aqueous solution is 1-3 mg / mL, and ferric chloride hexahydrate is added to the solution as a catalyst and oxidant, and its concentration is 10 times that of the pyrrole; the polymerization reaction time is 30-120 min.
[0020] The concentration of the pyrrole aqueous solution is more preferably 2.4 mg / mL, and the polymerization time is 60 min.
[0021] Specifically, the electrospun fiber membrane after ultrasonic treatment is immersed in a pyrrole solution, and then ferric chloride hexahydrate is added to the solution to cause pyrrole to polymerize on the fiber membrane to obtain polypyrrole (PPy).
[0022] Furthermore, a small amount of methyl orange can be added to the pyrrole solution to promote its dispersion.
[0023] The multifunctional conductive composite fiber membrane prepared by the present invention consists of a micron fiber layer and a nanofiber layer. The network structure of the fiber membrane facilitates the loading of conductive fillers. During stretching, the high strength of the micron fiber layer and the rich conductive filler content in the fiber network ensure a stable strain response signal, giving the fiber membrane a wide response range. In contrast, the nanofiber layer has many defects and low strength, and its fiber network structure is easily altered during stretching, increasing resistance change and thus improving sensitivity. Furthermore, the extensive distribution of fillers on the fiber membrane contributes to its outstanding photothermal performance.
[0024] In summary, the multifunctional conductive composite fiber membrane prepared by the present invention has a wide strain sensing response range (0-400%), high sensitivity (gauge factor GF up to 15684.11) and good cyclic stability under different strains. In addition, the fiber membrane's absorbance can be maintained above 92% in the ultraviolet-visible-near-infrared (UV-Vis-NIR) spectral range, and 100mW / cm 2 Under the irradiation intensity of 100 nm, the fiber membrane temperature can rise to 85°C after 95 seconds. This flexible conductive material has considerable application potential in wearable flexible electronics, smart medical care, human-computer interaction and other fields.
[0025] Compared with the prior art, the present invention has the following advantages:
[0026] The present invention prepares a multifunctional conductive composite fiber membrane with an asymmetric, or Janus, structure. The resulting conductive composite fiber membrane, when used as a strain sensor, exhibits a wide detection range, high sensitivity, and good cyclic stability under varying strains. Furthermore, the conductive composite fiber membrane exhibits outstanding photothermal performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is a scanning electron microscope image of the TPU micro-nano fiber membrane with Janus structure prepared in step 2) of Example 1. Figure 1 a and Figure 1 b Surface morphologies of the nanofiber side and the microfiber side, respectively;
[0028] Figure 2This is a scanning electron microscope image of the TPU / CB / PPy micro-nano fiber membrane with Janus structure prepared in Example 1. Figure 2 a and Figure 2 b are the nanofiber side and microfiber side of the TPU / CB / PPy micro-nanofiber membrane;
[0029] Figure 3 Fourier transform infrared (FTIR) spectra of the TPU micro-nano fiber membrane with Janus structure (step 2), TPU / CB micro-nano fiber membrane (step 4), and TPU / CB / PPy micro-nano fiber membrane (step 5) prepared in Example 1;
[0030] Figure 4 Comparison of the resistance values of the TPU conductive composite fiber membranes with a Janus structure prepared in Examples 1-4 and Comparative Example 1;
[0031] Figure 5 a is a comparison of the strain sensing performance of the TPU conductive composite fiber membranes prepared in Example 1 and Comparative Examples 1-3; Figure 5 b is the GF curve of the TPU / CB / PPy micro-nano fiber membrane of Example 1;
[0032] Figure 6 The resistance response curves of the TPU / CB / PPy micro-nano fiber membrane with Janus structure prepared in Example 1 subjected to stretching and releasing cycles at different strains (50%, 100%, 150%, 200%).
[0033] Figure 7 a is the UV-visible-near-infrared spectrum of the absorbance and reflectance of the TPU / CB / PPy micro-nano fiber membrane of Example 1; Figure 7 b is the TPU / CB / PPy micro-nano fiber membrane of Example 1 under different irradiation intensities (50 mW / cm 2 , 75mW / cm 2 , 100mW / cm 2 、125mW / cm 2 、150mW / cm 2 ) temperature curve. DETAILED DESCRIPTION
[0034] The technical solution of the present invention is described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto:
[0035] In the following examples, TPU pellets (density of about 1.12 g·cm -3 , code 1185A) was purchased from BASF; carbon black (CB, average particle size of about 30 nm, density 1.7-1.9 g / cm 3) were purchased from Cabot Corporation of the United States, but the above selection does not affect the technical effect of the present invention.
[0036] Example 1
[0037] A method for preparing a multifunctional conductive composite fiber membrane with a Janus structure, comprising the following steps:
[0038] 1) Weigh 5.8 g of TPU pellets into a 50 ml beaker, add 10 ml of DMF and 10 ml of THF, and stir magnetically for approximately 4 hours until the TPU pellets completely dissolve, resulting in a colorless, transparent solution. The resulting spinning solution has a TPU content of approximately 24 wt%. Separately, weigh 2.5 g of TPU pellets into a 50 ml beaker, add 10 ml of DMF and 10 ml of THF, and stir magnetically for approximately 2 hours to obtain a spinning solution with a TPU content of approximately 12 wt%.
[0039] 2) Electrospinning was performed using a 10mL medical syringe with 24wt% TPU spinning solution. The propulsion speed was set to 6mL / h, the applied voltage was 20kV, and a metal roller wrapped with aluminum foil as a receiving device was applied with a -300V voltage at a receiving distance of 20cm. The spinning time was 30 minutes. Electrospinning was then performed using a medical syringe with 12wt% TPU spinning solution. The propulsion speed was changed to 2.4mL / h, while other parameters remained unchanged. The spinning time was 30 minutes. After electrospinning, the fiber membrane was dried in a fume hood for at least 4 hours to obtain a TPU micro-nanofiber membrane with a Janus structure.
[0040] 3) Cut the fiber membrane into 1×4cm 2 The sample strips were treated with O2 plasma for 2 min.
[0041] 4) CB particles were added to ethanol to prepare a 10 mg / mL CB dispersion. The sample strip was placed in the dispersion and sonicated for 9 minutes at 70 W. The strip was then washed with deionized water and dried in a 65°C oven for 15 minutes to obtain a TPU / CB micro-nanofiber membrane.
[0042] 5) Weigh 0.12g of pyrrole and 0.024g of methyl orange and add them to 50mL of deionized water. Separately, weigh 1.2g of ferric chloride hexahydrate and add it to 50mL of deionized water. Precool the two solutions to 4°C, mix them in a 1:1 ratio, and then place them on the TPU / CB micro-nanofiber membrane. Polymerize the pyrrole at room temperature for 60 minutes. Then, remove the membrane, wash it with 0.1M hydrochloric acid and ethanol, and dry it in a 65°C oven for 15 minutes to obtain a TPU / CB / PPy micro-nanofiber membrane, i.e., a TPU conductive composite fiber membrane with a Janus structure.
[0043] Examples 2-4
[0044] The other steps are the same as those in Example 1, except that in step 5), the time for in-situ polymerization of pyrrole on the TPU / CB micro-nanofiber membrane is different. The polymerization time in Examples 2-4 is 30 min, 90 min, and 120 min, respectively.
[0045] Comparative Example 1
[0046] The specific preparation steps 1), 2), 3) and 4) are the same as those in Example 1, except that the pyrrole in-situ polymerization treatment operation in step 5) is not performed.
[0047] Comparative Example 2
[0048] The specific preparation steps 1), 2), 3) and 5) are the same as those in Example 1, except that the CB ultrasonic treatment operation in step 4) is not performed.
[0049] Comparative Example 3
[0050] 1) Weigh 5.8 g of TPU pellets into a 50 ml beaker, then add 10 mL of DMF and 10 mL of THF. Stir magnetically for approximately 4 hours until the TPU pellets are completely dissolved, resulting in a colorless, transparent solution. The resulting spinning solution contains approximately 24 wt% TPU.
[0051] 2) Electrospinning was performed using a 10 mL medical syringe to draw up the TPU spinning solution. The propulsion speed was set to 6 mL / h, the applied voltage was 20 kV, and a metal roller wrapped with aluminum foil as a receiving device was applied with a voltage of -300 V at a receiving distance of 20 cm. The spinning time was 30 min. After electrospinning, the fiber membrane was dried in a fume hood for at least 4 h to obtain a single-layer TPU fiber membrane.
[0052] 3) Cut the fiber membrane into 1×4cm 2 The sample strips were treated with O2 plasma for 2 min.
[0053] 4) CB particles were added to ethanol to prepare a 10 mg / mL CB dispersion. The sample strip was placed in the dispersion and sonicated for 9 minutes at 70 W. The strip was then washed with deionized water and dried in a 65°C oven for 15 minutes to obtain a TPU / CB fiber membrane.
[0054] 5) 0.12 g of pyrrole and 0.024 g of methyl orange were weighed into 50 mL of deionized water to prepare a solution, and 1.2 g of iron chloride hexahydrate was weighed into 50 mL of deionized water. Both solutions were pre-cooled to 4°C, mixed 1:1, and then placed into the TPU / CB fiber membrane, and pyrrole was allowed to polymerize for 60 min at room temperature. Then the membrane was taken out, washed with 0.1 M hydrochloric acid and ethanol, and placed in a 65°C oven for drying for 15 min. A TPU / CB / PPy fiber membrane, i.e., a TPU conductive composite fiber membrane without Janus structure, was obtained.
[0055] Performance test:
[0056] 1) Micro-morphology observation
[0057] The surfaces of the TPU micro-nano fiber membrane with Janus structure prepared in Example 1 of the present application and the TPU / CB / PPy micro-nano fiber membrane were subjected to gold spraying treatment, and then the micro-morphology of the surfaces of the samples was observed by using a scanning electron microscope (Carl Zeiss AG, Germany, model EV018).
[0058] Figure 1 a and Figure 1 b are the nanofiber side and the microfiber side of the Janus-structured electrospun TPU fiber membrane, respectively, and they have completely different surface morphologies. Figure 1 a shows that the nanofiber layer is composed of nanofibers (the diameters are mainly distributed between 300-600 nm) and microbeads. When the fiber membrane is stretched, the stress concentration effect caused by the microbead structure can intensify local damage, thereby enhancing the strain sensitivity. Figure 1 b is the microfiber layer, and the fiber size is mainly concentrated in 2-3 μm, and the strength is high, which can provide a wide strain response range for the sensor.
[0059] Figure 2 a and Figure 2 b are the nanofiber side and the microfiber side of the TPU / CB / PPy micro-nano fiber membrane with Janus structure, respectively, and it can be seen that the fillers are uniformly distributed on the surface of the fiber membrane.
[0060] 2) Infrared spectroscopy characterization
[0061] The FTIR spectrum was obtained by testing the infrared transmittance of the TPU micro-nano fiber membrane with Janus structure, the TPU / CB micro-nano fiber membrane and the TPU / CB / PPy micro-nano fiber membrane prepared in Example 1 of the present application on a Nicolet Nexus 870 spectrometer.
[0062] Figure 3The FTIR spectra of TPU micro-nano fiber membrane, TPU / CB micro-nano fiber membrane and TPU / CB / PPy micro-nano fiber membrane are shown in Figure 2. The infrared spectrum of TPU / CB / PPy micro-nano fiber membrane has a 1455cm-1 peak related to the pyrrole ring structure. -1 and 965cm -1 The appearance of these characteristic peaks proves that PPy is successfully polymerized on the fiber membrane.
[0063] 3) Sensing performance test
[0064] The electrical conductivity of Examples 1 to 4 of the present invention and Comparative Example 1 was studied using a digital precision multimeter (Tektronix, DMM 4050).
[0065] As a conductive material, the TPU conductive composite fiber membrane should have a lower resistance value as possible. Figure 4 The resistance values of the samples from Examples 1-4 and Comparative Example 1 are compared. As can be seen from the figure, the resistance values of Comparative Example 1 (no pyrrole polymerization), Example 2 (pyrrole polymerization time 30 minutes), and Example 1 (pyrrole polymerization time 60 minutes) show a clear downward trend. There is no significant difference in resistance between Example 1 (pyrrole polymerization time 60 minutes), Example 3 (pyrrole polymerization time 90 minutes), and Example 4 (pyrrole polymerization time 120 minutes) (all around 350Ω), indicating that in-situ pyrrole polymerization is essentially complete within 60 minutes.
[0066] A universal tensile testing machine (UTM2203) and a digital precision multimeter (Tektronix, DMM 4050) were used to study the strain sensing performance of Example 1 and Comparative Examples 1-3. To reduce contact resistance with the electrodes during the sensing performance test, conductive silver paste was applied to both ends of the fiber membrane.
[0067] Figure 5 a is a comparison of the strain sensing performance of the TPU conductive composite fiber membranes prepared in Example 1 and Comparative Examples 1-3. It can be seen that the sensing range of several TPU conductive composite fiber membranes can reach 400% strain, and the resistance response ΔR / R0 of the sensor with the Janus asymmetric structure design is significantly higher than that of the sensor without the Janus structure (comparison between the TPU / CB / PPy micro-nano fiber membrane of Example 1 and the TPU / CB / PPy fiber membrane of Comparative Example 3). In addition, the combined use of the two fillers will also improve the resistance response ΔR / R0 of the sensor (comparison between the TPU / CB / PPy micro-nano fiber membrane of Example 1 and the TPU / CB micro-nano fiber membrane of Comparative Example 1 and the TPU / PPy micro-nano fiber membrane of Comparative Example 2). That is, while ensuring a wide strain sensing range, the resistance response ΔR / R0 of the TPU / CB / PPy micro-nano fiber membrane of Example 1 is significantly higher than that of other designs. Figure 5b is the GF curve of the TPU / CB / PPy micro-nano fiber membrane of Example 1, and it can be seen that the GF can reach a maximum of 15684.11.
[0068] Figure 6 This is the resistance response curve of the TPU / CB / PPy micro-nano fiber membrane with Janus structure prepared in Example 1 subjected to stretching and releasing cycles with different strains (50%, 100%, 150%, 200%). It can be seen that the fiber membrane has good resolution for strains of different sizes, and the response signal is stable.
[0069] 4) Photothermal performance test
[0070] The reflectivity and transmittance of the TPU / CB / PPy micro-nanofiber membrane prepared in Example 1 of the present invention were measured using a Topology UV-Vis-NIR spectrophotometer TP760. The absorbance of the fiber membrane was calculated by subtracting the reflectivity and transmittance from 100%. Simulated sunlight of varying intensities was obtained using a CEL-HXF300 photocatalytic xenon lamp in conjunction with a CEL-FZ-A radiometer. Additionally, the surface temperature of the fiber membrane was recorded using an infrared thermal imager (FILR E75).
[0071] Figure 7 a is the UV-visible-near-infrared spectrum of the absorbance and reflectance of the TPU / CB / PPy micro-nano fiber membrane of Example 1. The absorbance of the fiber membrane can be maintained above 92% within the wavelength range of 250-2500nm, and can reach a maximum of 96.97%.
[0072] Figure 7 b is the temperature curve of the TPU / CB / PPy micro-nano fiber membrane of Example 1 under different irradiation intensities. Under the irradiation of the xenon lamp, the surface temperature of the fiber membrane rises rapidly and reaches equilibrium, and the equilibrium temperature increases with the increase of irradiation intensity. 2 Under the irradiation intensity of 100 nm, the fiber membrane can heat up to 85°C after 95 seconds. This shows that the TPU / CB / PPy micro-nano fiber membrane has excellent photothermal conversion performance and can be used in photothermal-assisted therapy.
Claims
1. A method for preparing a multifunctional conductive composite fiber membrane with a Janus structure, characterized in that: Here are the steps: 1) Preparation of Janus-structured electrospun fiber membranes consisting of nanofiber layers and microfiber layers; 2) Plasma treatment of Janus structure electrospun fiber membrane; 3) The treated Janus structure electrospun fiber membrane is ultrasonically treated and subjected to in-situ polymerization of conductive fillers to form a conductive network to obtain the multifunctional conductive composite fiber membrane.
2. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 1, wherein: In step 1), the order of spinning the micron fiber layer first and then the nanofiber layer is adopted.
3. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 1, wherein: In step 1), the nanofiber layer and the micron fiber layer are obtained by electrospinning from spinning solutions with a low concentration of 10-12 wt% and a high concentration of 20-24 wt%, respectively.
4. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 3, wherein: The spinning solution is obtained by dissolving TPU in a solvent of equal volumes of DMF and THF.
5. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 1, wherein: In step 2), the plasma treatment is O2 plasma treatment, and the treatment time is 1-3 minutes.
6. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 1, wherein: In step 3), the fiber membrane is immersed in a dispersion of a first conductive filler and treated with ultrasound; the first conductive filler is one of carbon black, graphene, reduced graphene oxide, carbon nanotubes, and MXene, the dispersion medium is anhydrous ethanol, and the concentration of the first conductive filler is 5-15 mg / mL.
7. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 6, wherein: The ultrasonic power was 70 W and the ultrasonic time was 3-15 min.
8. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 6, wherein: The electrospun fiber membrane after ultrasonic treatment is immersed in a second conductive filler solution to carry out in-situ polymerization reaction, wherein the second conductive filler is pyrrole and a catalyst is added to the solution.
9. The method for preparing a multifunctional conductive composite fiber membrane having a Janus structure according to claim 8, wherein: The concentration of the pyrrole aqueous solution is 1-3 mg / mL, and ferric chloride hexahydrate is added to the solution, and its concentration is 10 times that of the pyrrole; the polymerization reaction time is 30-120 min.
10. A multifunctional conductive composite fiber membrane with a Janus structure obtained by the preparation method according to any one of claims 1 to 9.