A photoelectric dual-mode stress-strain sensing fiber and its preparation method

Abstract

This invention discloses a photoelectric dual-mode stress-strain sensing fiber and its preparation method, belonging to the field of materials engineering technology. The invention first uses wet spinning to continuously prepare TPU (thermoplastic polyurethane)-based electrical sensing fibers as electrical signal sensing modules. Then, hard-core, soft-shell photonic crystal microspheres with self-forming elastic membranes are synthesized as optical signal sensing modules. Finally, the TPU electrical sensing fibers are dip-coated with a hard-core, soft-shell photonic crystal microsphere emulsion to rapidly prepare the photoelectric dual-mode sensing fibers.

Description

Technical Field

[0001] The present invention belongs to the technical field of material engineering, and in particular relates to a photoelectric dual-mode stress-strain sensing fiber and a preparation method thereof. Background Art

[0002] In sensors with optoelectronic dual-signal responses, the optical signal provides direct visual information, while the electrical signal provides precise strain quantification. Currently, various optical materials have been developed for strain sensing, such as organic light-emitting diodes, inorganic phosphors, organic chromophores, and photonic crystals. Among these materials, mechanochromic photonic crystals are considered one of the most promising candidates, primarily because they can produce an immediate and intuitive dynamic optical signal response without consuming any energy. On the other hand, the strain-dependent electrical signal can serve as an effective indicator for quantifying deformation. In particular, highly sensitive electronic strain sensors have been widely explored for monitoring human motion with small strains. By combining mechanochromic photonic crystals with highly sensitive electronic strain sensors, several interactive wearable devices with optical / electrical dual-signal outputs have been realized for monitoring human motion.

[0003] When used directly as optical signal sensors, traditional hard photonic crystal microspheres (such as polystyrene, polymethyl methacrylate, and silica) have a deformation of less than 1% and poor biocompatibility, making them difficult to meet the flexibility and stretchability requirements of wearable applications. Currently, electrical sensing fibers cannot be directly combined with traditional hard photonic crystal microspheres, as there is no effective bonding or adhesion between the fibers and the microspheres. Furthermore, the microspheres cannot directly form strong interactions with each other without the aid of other media, making the fabrication of fiber-based optoelectronic dual-mode stress and strain sensors difficult.

[0004] When further selecting the adhesion medium, not only should the photonic crystal layer be elastic, but also the adhesion between it and the electrical sensing fiber should not affect the electrical sensing effect, which further increases the difficulty of preparing fiber-type photoelectric dual-mode stress and strain sensors. Zhao et al. mixed SiO2 with polyethylene glycol phenyl ether acrylate (PEGPEA), injected the mixed solution into a capillary, used the capillary as a template to initiate polymerization under ultraviolet light to form an optical signal sensing fiber, and then sealed it with an ion conductive gel to prepare a photoelectric dual-mode stress and strain sensing fiber. This preparation method is not only complicated, but also the gel-type fiber is easily exposed to air, which can easily cause unstable signal transmission, which is very unfavorable for use in an in vitro environment (Zhao RL, He Y, He Y, et al. Dual-Mode Fiber Strain Sensor Based on MechanochromicPhotonic Crystal and Transparent Conductive Elastomer for Human MotionDetection[J]. ACS Applied Materials&Interfaces, 2023, 15(12): 16063-16071.).

[0005] The preparation steps of fiber-based photoelectric dual-mode sensors are very complicated. How to simply and quickly prepare photoelectric dual-mode sensing fibers is an urgent problem to be solved. Summary of the Invention

[0006] Technical issues:

[0007] Directly combining traditional hard photonic crystal microspheres with electrical sensing fibers cannot produce optoelectronic dual-mode sensing fibers, and adding adhesive materials will affect the tensile properties of the fiber's optoelectronic layers, thereby affecting the optoelectronic dual-mode sensing performance.

[0008] Technical solution:

[0009] In order to solve the above problems, the present invention first uses wet spinning to continuously prepare TPU (thermoplastic polyurethane)-based electrical sensing fibers as electrical signal sensing modules, then synthesizes hard-core and soft-shell structured photonic crystal microspheres that can form their own elastic membranes as optical signal sensing modules, and finally dips the TPU electrical sensing fibers into a hard-core and soft-shell structured photonic crystal microsphere emulsion to achieve the rapid preparation of optoelectronic dual-mode sensing fibers.

[0010] The purpose of the present invention is to provide a photoelectric dual-mode stress and strain sensing fiber and a preparation method thereof, which is simple and convenient and can realize the continuous preparation of the photoelectric dual-mode stress and strain sensing fiber.

[0011] In addition, the present invention also provides the application of the photoelectric dual-mode stress-strain sensing fiber in sensing.

[0012] In order to achieve the aforementioned object of the invention, the present invention adopts the following technical solutions:

[0013] The present invention provides a photoelectric dual-mode stress-strain sensing fiber, comprising a TPU electrical sensing fiber core layer and a light sensing cortex formed by hard-core and soft-shell photonic crystal microspheres. The hard-core and soft-shell photonic crystal microspheres can self-assemble and form a light sensing elastic film, displaying structural color, thereby realizing light signal sensing under stress and strain.

[0014] The present invention also provides a method for preparing the photoelectric dual-mode stress and strain sensing fiber, comprising the following steps:

[0015] S1, dispersing TPU in DMF and mixing to obtain TPU / DMF spinning solution;

[0016] S2. Dispersing the conductive material in DMF and mixing to obtain a conductive material DMF dispersion;

[0017] S3, mixing the TPU / DMF spinning solution obtained in S1 with the conductive material DMF dispersion obtained in S2, loading the mixture into a syringe and preparing a TPU electrical sensing fiber by wet spinning;

[0018] S4, preparing a photonic crystal microsphere emulsion with a hard-core and soft-shell structure by seed emulsion polymerization;

[0019] S5, dip-coating the TPU electrical sensing fiber prepared in S3 into the hard-core soft-shell photonic crystal microsphere emulsion prepared in S4, then taking it out and drying it to obtain a photoelectric dual-mode stress-strain sensing fiber;

[0020] The method for preparing the photonic crystal microsphere emulsion with a hard-core and soft-shell structure in S4 includes:

[0021] (a) emulsifying a portion of a hard core monomer, a crosslinking agent, an emulsifier, and water, and then adding an initiator to react to obtain a polymer seed emulsion;

[0022] (b) adding another portion of the hard core monomer, the crosslinking agent, and the initiator to the obtained polymer seed emulsion, and polymerizing to obtain a hard core microsphere system;

[0023] (c) adding a soft shell monomer, a crosslinking agent, and an initiator to the obtained hard core microsphere system to initiate polymerization to obtain a photonic crystal microsphere emulsion with a hard core and soft shell structure.

[0024] The hard core monomer is one or more of styrene (St), methyl methacrylate (MMA), and acrylonitrile (AN).

[0025] The soft shell monomer is selected from:

[0026] ① Ethyl acrylate (EA), or

[0027] ② A combination of ethyl acrylate (EA) and butyl acrylate (BA), or

[0028] ③ Combination of methyl methacrylate (MMA) and butyl acrylate (BA).

[0029] In one embodiment of the present invention, the mass ratio of ethyl acrylate (EA) to butyl acrylate (BA) in the soft shell monomer is (19-20):(0-1).

[0030] In one embodiment of the present invention, the mass ratio of methyl methacrylate (MMA) to butyl acrylate (BA) in the soft shell monomer is 1:3.

[0031] In one embodiment of the present invention, step S1, TPU is added to DMF, and magnetic stirring is carried out at room temperature for 4 hours to obtain TPU / DMF spinning solution.

[0032] In one embodiment of the present invention, in step S1, TPU is thermoplastic polyurethane, DMF is N,N-dimethylformamide, and the concentration of TPU / DMF spinning solution is 15-25 wt.%, more preferably 20-22.5 wt.%.

[0033] In one embodiment of the present invention, in step S2, the conductive material is added to DMF, and ultrasonic dispersion is performed to obtain a DMF dispersion of the conductive material.

[0034] In one embodiment of the present invention, the conductive material in step S2 can be one or more of conductive materials such as conductive carbon black (CB), graphene oxide (GO), reduced graphene oxide (rGO), carbon nanotubes (CNTs), MXene, silver nanowires (AgNWs), and silver nanoparticles (AgNPs).

[0035] In one embodiment of the present invention, the concentration of the conductive material DMF dispersion in step S2 is 10-40 mg / mL, more preferably 30-40 mg / mL.

[0036] In one embodiment of the present invention, in step S3, the TPU / DMF solution in steps S1 and S2 and the conductive material DMF dispersion are mixed in a 1:1 ratio, loaded into a syringe and then wet-spinned to prepare a TPU electrical sensing fiber, and the coagulation bath is an isopropyl alcohol water calcium chloride mixed solution (IPA:H2O=1:2, 5wt.% CaCl2).

[0037] In one embodiment of the present invention, step S4, preparing photonic crystal microspheres with a hard-core and soft-shell structure by seed emulsion polymerization:

[0038] First, a hard monomer, a crosslinking agent, an emulsifier, and water are emulsified for a certain time, and then an initiator is added. Polymerization is initiated under certain temperature conditions to obtain a polymer seed emulsion, wherein the particle size of the polymer seed is about 120 nm and the polymer dispersibility index (PDI) is less than 0.08. The emulsification time is 10-30 minutes, the temperature is 70-85°C, and the polymerization time is 1-1.5 hours;

[0039] Secondly, hard monomer, crosslinking agent and initiator are added again to initiate polymerization to obtain hard core microspheres with a particle size of about 170-220 nm and a PDI of less than 0.08, wherein the polymerization time is 1.5-2.5 hours;

[0040] One or more soft monomers or a certain proportion of soft and hard monomers, a crosslinking agent, and an initiator are added to the reaction system to initiate polymerization to obtain hard-core soft-shell photonic crystal microspheres with a particle size of about 200-300nm and a PDI of less than 0.08. The polymerization time is 1.5-2.5h.

[0041] In one embodiment of the present invention, the syringe used in step S3 is a 10 mL syringe, the wet spinning injection rate is 50-80 mL / min, and the spinneret size is 15-18G.

[0042] In one embodiment of the present invention, in step S4, the mass ratio of the hard core monomer in (a) to the hard core monomer in (b) is 1:(1-2), and specifically 1:1.5.

[0043] In one embodiment of the present invention, in step S4, the emulsifier used for emulsification is one of sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate.

[0044] In one embodiment of the present invention, in step S4, the emulsifier accounts for 0.15-0.25 wt.% of the total monomer concentration; specifically, 0.2 wt.% can be selected. (Total monomer refers to the total mass of the hard core monomer and the soft shell monomer.)

[0045] In one embodiment of the present invention, in step S4, the cross-linking agent may be one or more diene cross-linking agents such as divinylbenzene (DVB), allyl methacrylate (ALMA), and isoprene.

[0046] In one embodiment of the present invention, in step S4, the amount of the cross-linking agent in (a) or (b) relative to the hard core in this step is 10-14 wt.%.

[0047] In one embodiment of the present invention, in step S4, the amount of the crosslinking agent in (c) relative to the soft shell monomer in this step is 0.2-1.0 wt.%.

[0048] In one embodiment of the present invention, in step S4, the initiator may also be one or more of ammonium persulfate (APS), potassium persulfate, and sodium persulfate.

[0049] In one embodiment of the present invention, in step S4, the ratio of initiator to monomer in (a), (b) or (c) is 0.5-1 wt.%.

[0050] In one embodiment of the present invention, the dipping time in step S5 is 10-60 seconds, and the drying time is 10-60 seconds.

[0051] The present invention provides a photoelectric dual-mode stress and strain sensing fiber prepared based on the above method.

[0052] The present invention also provides application of the photoelectric dual-mode stress-strain sensing fiber in preparing a photoelectric signal sensing component.

[0053] The present invention also provides an application of the photoelectric dual-mode stress-strain sensing fiber in the construction of a human joint motion monitoring product.

[0054] Beneficial effects of the present invention:

[0055] The preparation method of the photoelectric dual-mode stress-strain sensing fiber prepared by the present invention is simple and rapid, easy to continuously produce, and does not require the addition of additional adhesive materials, thereby avoiding the influence of adhesive materials on electrical signal sensing and optical signal sensing; thermoplastic polyurethane has good biocompatibility, and the photonic crystal layer is not only non-toxic but also can better protect the internal electrical sensing layer; the TPU electrical sensing fiber is distributed with a large number of holes, which can improve the sensitivity of electrical signal sensing and can monitor small-amplitude movements; the optical signal sensing layer is affected by the soft shell layer and has good elasticity. When subjected to stress and strain, it can change the spacing between the photonic crystal microspheres, thereby causing changes in the optical signal. These characteristics make the photoelectric dual-mode stress-strain sensing fiber have broad application prospects in the field of human motion monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a flow chart of the method for preparing the photoelectric dual-mode stress and strain sensing fiber of the present invention;

[0057] Figure 2 Electron microscope images of the MXene / TPU fiber and optoelectronic dual-mode stress-strain sensing fiber provided in Example 2. DETAILED DESCRIPTION

[0058] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with some embodiments, but the following examples are not used to limit the present invention.

[0059] Test method:

[0060] Electrical signal sensing test: The photoelectric dual-mode stress-strain sensing fiber was clamped in an electronic universal material testing machine with a spacing of 10 mm. Copper wires were connected from both ends and then connected to a desktop digital multimeter via wires to test the resistance change caused by the fiber being stretched:

[0061]

[0062] Where GF is the sensing sensitivity, R is the stretching resistance, R0 is the initial resistance, and ε is the strain

[0063] Optical signal sensing test: The photoelectric dual-mode stress-strain sensing fiber is fixed, and a fiber optic spectrometer is used to test the spectral changes caused by fiber stretching.

[0064] Example 1:

[0065] Step S1, TPU / DMF spinning solution preparation: 2.25 g of TPU particles were weighed and added to 7.75 g of DMF solution, and magnetic stirring was performed for 4 h to obtain a 22.5 wt.% TPU / DMF spinning solution.

[0066] Step S2, preparation of Ti3C2Tx MXene DMF dispersion: 400 mg of MXene was added to 10 mL of DMF solution and ultrasonically dispersed to obtain a MXene / DMF dispersion with a concentration of 40 mg / mL.

[0067] Step S3, preparation of MXene / TPU fiber: The prepared 22.5wt.% TPU / DMF spinning solution and 40mg / mLMXene / DMF dispersion were mixed in a volume ratio of 1:1, mixed by a vortex mixer for 10min, and then ultrasonically mixed for 10min to obtain a uniform MXene / TPU / DMF spinning solution. The spinning solution was loaded into a 10mL syringe with a spinneret of 16G, and the spinning solution was injected into a coagulation bath (IPA:H2O=1:2, 5wt.%CaCl2) through a syringe pump (injection rate of 80mL) to coagulate to obtain porous MXene / TPU fiber.

[0068] Step S4, preparation of PS@P(MMA-BA) core-shell structure photonic crystal microspheres:

[0069] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0070] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 220 nm.

[0071] (3) 5 g MMA, 15 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(MMA-BA) photonic crystal microsphere emulsion with a particle size of about 300 nm.

[0072] Step S5, preparation of photoelectric dual-mode stress and strain sensing fiber: 10 mL of PS@P(MMA-BA) emulsion was added to a culture dish, and the porous MXene / TPU fiber was immersed therein. After 10 seconds, the fiber was taken out and placed in an oven at 60°C for 30 seconds to dry. The red photoelectric dual-mode stress and strain sensing fiber was obtained.

[0073] Example 2:

[0074] Steps S1, S2, and S3 are the same as those in Example 1.

[0075] Step S4, preparation of PS@P(MMA-BA) core-shell structure photonic crystal microspheres:

[0076] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.066 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0077] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 200 nm.

[0078] (3) 5 g MMA, 15 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(MMA-BA) photonic crystal microsphere emulsion with a particle size of about 280 nm.

[0079] Step S5, preparation of photoelectric dual-mode stress and strain sensing fiber: 10 mL of PS@P(MMA-BA) emulsion was added to a culture dish, and the porous MXene / TPU fiber was immersed in it. After 10 seconds, it was taken out and placed in a 60°C oven to dry for 30 seconds. The green photoelectric dual-mode stress and strain sensing fiber was taken out.

[0080] Example 3:

[0081] Step S1 is the same as in Example 1

[0082] Step S2, preparation of rGO DMF dispersion: 400 mg of rGO was added to 10 mL of DMF solution and ultrasonically dispersed to obtain an rGO / DMF dispersion with a concentration of 40 mg / mL.

[0083] Step S3, preparation of rGO / TPU fibers: the experimental method is the same as that of Example 1.

[0084] Step S4, preparation of PS@P(EA-BA) core-shell structure photonic crystal microspheres:

[0085] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.066 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0086] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 200 nm.

[0087] (3) 19 g EA, 1 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(EA-BA) photonic crystal microsphere emulsion with a particle size of about 280 nm.

[0088] Step S5, preparation of optoelectronic dual-mode stress-strain sensing fiber: 10 mL of PS@P(EA-BA) emulsion was added to a culture dish, and the porous rGO / TPU fiber was immersed in it. After 10 seconds, it was taken out and placed in a 60°C oven to dry for 30 seconds. The green optoelectronic dual-mode stress-strain sensing fiber was taken out.

[0089] Example 4:

[0090] Step S1 is the same as in Example 1

[0091] Step S2, preparation of CB / MXene DMF dispersion: 200 mg of CB and 200 mg of MXene were added to 10 mL of DMF solution and ultrasonically dispersed to obtain a CB / MXene / DMF dispersion with a conductive material concentration of 40 mg / mL.

[0092] Step S3, preparation of CB / MXene / TPU fibers: the experimental method is the same as that of Example 1.

[0093] Step S4, preparation of PAN@P(EA-BA) core-shell structure photonic crystal microspheres:

[0094] (1) 5 g of AN and 0.5 g of DVB were added to 100 mL of deionized water containing 0.066 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PAN seeds with a particle size of approximately 120 nm.

[0095] (2) 7.5 g of AN and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PAN core with a particle size of about 200 nm.

[0096] (3) 19 g EA, 1 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structured PAN@P(EA-BA) photonic crystal microsphere emulsion with a particle size of about 280 nm.

[0097] Step S5, preparation of the optoelectronic dual-mode stress-strain sensing fiber: 10 mL of PAN@P(EA-BA) emulsion was added to a culture dish, and the porous CB / MXene / TPU fiber was immersed therein. After 10 seconds, the fiber was removed and placed in an oven at 60°C to dry for 30 seconds. The green optoelectronic dual-mode stress-strain sensing fiber was obtained.

[0098] Example 5:

[0099] Step S1 is the same as in Example 1

[0100] Step S2, preparation of AgNWs / MXene DMF dispersion: 200 mg of AgNWs and 200 mg of MXene were added to 10 mL of DMF solution and ultrasonically dispersed to obtain an AgNWs / MXene / DMF dispersion with a conductive material concentration of 40 mg / mL.

[0101] Step S3, preparation of AgNWs / MXene / TPU fibers: the experimental method is the same as that in Example 1.

[0102] Step S4, preparation of PS@PEA core-shell structure photonic crystal microspheres:

[0103] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0104] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 220 nm.

[0105] (3) 20 g EA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structured PS@PEA photonic crystal microsphere emulsion with a particle size of about 300 nm.

[0106] Step S5, preparation of the optoelectronic dual-mode stress-strain sensing fiber: 10 mL of PS@PEA emulsion was added to a culture dish, and the porous AgNWs / MXene / TPU fiber was immersed in it. After 10 seconds, it was pulled out and placed in a 60°C oven to dry for 30 seconds. The red optoelectronic dual-mode stress-strain sensing fiber was taken out.

[0107] Example 6:

[0108] Step S1 is the same as in Example 1

[0109] Step S2, preparation of AgNPs / MXene DMF dispersion: 200 mg of AgNPs and 200 mg of MXene were added to 10 mL of DMF solution and ultrasonically dispersed to obtain an AgNPs / MXene / DMF dispersion with a conductive material concentration of 40 mg / mL.

[0110] Step S3, preparation of AgNPs / MXene / TPU fibers: the experimental method is the same as that in Example 1.

[0111] Step S4, preparation of PMMA@P(EA-BA) core-shell structure photonic crystal microspheres:

[0112] (1) 5 g of MMA and 0.5 g of DVB were added to 100 mL of deionized water containing 0.066 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PMMA seeds with a particle size of approximately 120 nm.

[0113] (2) 7.5 g MMA and 1 g DVB were added to the reaction system, and then 0.05 g APS was added to initiate polymerization for 1.5 h to obtain a PMMA core with a particle size of about 200 nm.

[0114] (3) 19 g EA, 1 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PMMA@P(EA-BA) photonic crystal microsphere emulsion with a particle size of about 280 nm.

[0115] Step S5, preparation of the optoelectronic dual-mode stress and strain sensing fiber: 10 mL of PMMA@P(EA-BA) emulsion was added to a culture dish, and the porous AgNPs / MXene / TPU fiber was immersed in it. After 10 seconds, it was taken out and placed in a 60°C oven to dry for 30 seconds. The green optoelectronic dual-mode stress and strain sensing fiber was taken out.

[0116] Comparative Example 1:

[0117] Step S1 is the same as in Example 1

[0118] Step S2: prepare 10 mg / mL MXene / DMF dispersion using the same method as in Example 1.

[0119] Step S3, preparation of MXene / TPU fiber, the method is the same as Example 1

[0120] Step S4,

[0121] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0122] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 220 nm.

[0123] Step S5, preparation of photoelectric dual-mode stress and strain sensing fiber: 10 mL of PS emulsion was added to a centrifuge tube, and the porous MXene / TPU fiber was immersed in the centrifuge tube. After 10 seconds, the fiber was lifted out and placed in a 60°C oven to dry for 30 seconds. The hard-shell photoelectric dual-mode stress and strain sensing fiber was obtained.

[0124] Comparative Example 2:

[0125] Step S1, TPU / DMF spinning solution preparation: 1.5 g of TPU particles were weighed and added to 8.5 g of DMF solution, and magnetic stirring was performed for 4 h to obtain a 15 wt.% TPU / DMF spinning solution.

[0126] Step S2 is the same as in Example 1

[0127] Step S3, preparation of porous MXene / TPU fiber: The prepared 15wt.% TPU / DMF spinning solution and 40mg / mL MXene / DMF dispersion were mixed in a ratio of 1:1, mixed by vortex mixer for 10min, and then ultrasonically mixed for 10min to obtain a uniform MXene / TPU / DMF spinning solution. The spinning solution was loaded into a 10mL syringe with a spinneret of 16G, and the spinning solution was injected into a coagulation bath (IPA:H2O=1:2, 5wt.%CaCl2) through a syringe pump (injection rate of 80mL) to coagulate to obtain porous MXene / TPU fiber.

[0128] Step S4, preparation of PS@P(MMA-BA) core-shell structure photonic crystal microspheres:

[0129] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.070 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0130] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 170 nm.

[0131] (3) 5 g MMA, 15 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(MMA-BA) photonic crystal microsphere emulsion with a particle size of about 210 nm.

[0132] Step S5, preparation of photoelectric dual-mode stress and strain sensing fiber: 10 mL of PS@P(MMA-BA) emulsion was added to a culture dish, and the porous MXene / TPU fiber was immersed in it. After 10 seconds, it was lifted out and placed in a 60°C oven to dry for 30 seconds. The purple photoelectric dual-mode stress and strain sensing fiber was taken out.

[0133] Comparative Example 3:

[0134] Step S1, TPU / DMF spinning solution preparation: 2.5 g of TPU particles were weighed and added to 7.5 g of DMF solution, and magnetic stirring was performed for 4 h to obtain a 25 wt.% TPU / DMF spinning solution.

[0135] Step S2 is the same as in Example 1

[0136] Step S3, preparation of porous MXene / TPU fiber: The prepared 25wt.% TPU / DMF spinning solution and 40mg / mL MXene / DMF dispersion were mixed in a ratio of 1:1, mixed by vortex mixer for 10min, and then ultrasonically mixed for 10min to obtain a uniform MXene / TPU / DMF spinning solution. The spinning solution was loaded into a 10mL syringe with a spinneret of 16G, and the spinning solution was injected into a coagulation bath (IPA:H2O=1:2, 5wt.%CaCl2) through a syringe pump (injection rate of 80mL) to coagulate to obtain porous MXene / TPU fiber.

[0137] Step S4, preparation of PS@PBA core-shell structure photonic crystal microspheres:

[0138] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0139] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 220 nm.

[0140] (3) 19 g EA, 1 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@PBA photonic crystal microsphere emulsion with a particle size of about 320 nm.

[0141] Step S5, preparation of photoelectric dual-mode stress and strain sensing fiber: 10 mL of PS@PBA emulsion was added to a culture dish, and the porous MXene / TPU fiber was immersed in it. After 10 seconds, it was taken out and placed in a 60°C oven to dry for 30 seconds. The white photoelectric dual-mode stress and strain sensing fiber was taken out.

[0142] Comparative Example 4:

[0143] Step S1 is the same as in Example 1

[0144] Step S2: prepare 10 mg / mL MXene / DMF dispersion using the same method as in Example 1.

[0145] Step S3, preparation of MXene / TPU fiber, the method is the same as Example 1

[0146] Step S4,

[0147] (1) 12.5 g of St and 1.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.1 g of APS was then added to initiate polymerization for 2.5 h to obtain a PS core.

[0148] (2) 19 g EA, 1 g BA and 0.04 g ALMA were added to the reaction system, and then 0.1 g APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(EA-BA) photonic crystal microsphere emulsion.

[0149] Step S5, preparation of photoelectric dual-mode stress and strain sensing fiber: 10 mL of PS emulsion was added to a centrifuge tube, and the porous MXene / TPU fiber was immersed in the centrifuge tube. After 10 seconds, the fiber was lifted out and placed in a 60°C oven to dry for 30 seconds. The hard-shell photoelectric dual-mode stress and strain sensing fiber was obtained.

[0150] Table 1. Comparison of results between Examples 1-6 and Comparative Examples 1-4

[0151]

[0152]

[0153]

[0154] Example 7: Optimization of TPU concentration in S1

[0155] S1, TPU / DMF spinning solution preparation: Weigh a certain amount of TPU particles and add them to a certain amount of DMF solution, keeping the total amount constant at 10 g. Magnetic stirring was performed for 4 h to obtain TPU / DMF spinning solutions of different concentrations (as shown in Table 2).

[0156] S2-S5 are the same as in Example 1.

[0157] The results are shown in Table 2.

[0158] Table 2

[0159]

[0160]

[0161] Example 8: Optimization of the concentration of conductive material in S3

[0162] S1 is the same as Example 1.

[0163] S2, Preparation of Ti3C2Tx MXene DMF dispersion: A certain amount of MXene (shown in Table 3) was added to 10 mL of DMF solution and ultrasonically dispersed to obtain a MXene / DMF dispersion of a certain concentration.

[0164] S3-S5 are the same as in Example 1.

[0165] The results are shown in Table 3.

[0166] Table 3

[0167]

[0168]

[0169] Example 9: Optimization of the Combination Ratio of Soft Shell Monomers in Step S4 (3)

[0170] S1-S3 refer to Example 1, and only S4 is adjusted:

[0171] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0172] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.05 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 220 nm.

[0173] (3) A certain amount of EA, BA (as shown in Table 4) and 0.04 g of ALMA were added to the reaction system, and then 0.1 g of APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(EA-BA) photonic crystal microsphere emulsion.

[0174] S5 refers to Example 1.

[0175] The results are shown in Table 4.

[0176] Table 4

[0177]

[0178]

[0179] Example 10: Optimization of the combination ratio of monomers for soft shell in step (3) of S4

[0180] S1-S3 refer to Example 1, and only S4 is adjusted:

[0181] (1) 5 g of St and 0.5 g of DVB were added to 100 mL of deionized water containing 0.065 g of SDS and emulsified at 300 rpm for 30 min. The reaction temperature was then raised to 85 °C and maintained for 10 min. 0.05 g of APS was then added to initiate polymerization for 1 h to obtain PS seeds with a particle size of approximately 120 nm.

[0182] (2) 7.5 g of St and 1 g of DVB were added to the reaction system, and then 0.08 g of APS was added to initiate polymerization for 1.5 h to obtain a PS core with a particle size of about 230 nm.

[0183] (3) A certain amount of MMA, BA (as shown in Table 5) and 0.04 g of ALMA were added to the reaction system, and then 0.1 g of APS was added to initiate polymerization for 1.5 h to obtain a core-shell structure PS@P(MMA-BA) photonic crystal microsphere emulsion.

[0184] S5 refers to Example 1.

[0185] The results are shown in Table 5.

[0186] Table 5

[0187]

[0188] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a photoelectric dual-mode stress-strain sensing fiber, characterized in that: The following steps are involved: S1, dispersing TPU in DMF and mixing to obtain TPU / DMF spinning solution; S2. Dispersing the conductive material in DMF and mixing to obtain a conductive material DMF dispersion; S3, mixing the TPU / DMF spinning solution obtained in S1 with the conductive material DMF dispersion obtained in S2, loading the mixture into a syringe and preparing a TPU electrical sensing fiber by wet spinning; S4, preparing a photonic crystal microsphere emulsion with a hard-core and soft-shell structure by seed emulsion polymerization; S5, dip-coating the TPU electrical sensing fiber prepared in S3 into the hard-core soft-shell photonic crystal microsphere emulsion prepared in S4, then taking it out and drying it to obtain a photoelectric dual-mode stress-strain sensing fiber; The method for preparing the photonic crystal microsphere emulsion with a hard-core and soft-shell structure in S4 includes: (a) emulsifying a portion of a hard core monomer, a crosslinking agent, an emulsifier, and water, and then adding an initiator to react to obtain a polymer seed emulsion; (b) adding another portion of the hard core monomer, the crosslinking agent, and the initiator to the obtained polymer seed emulsion, and polymerizing to obtain a hard core microsphere system; (c) adding a soft shell monomer, a crosslinking agent, and an initiator to the obtained hard core microsphere system to initiate polymerization to obtain a photonic crystal microsphere emulsion with a hard core and soft shell structure; The hard core monomer is one or more of styrene, methyl methacrylate, and acrylonitrile; The soft shell monomer is selected from: (1) Ethyl acrylate, or (2) a combination of ethyl acrylate and butyl acrylate, or (3) a combination of methyl methacrylate and butyl acrylate; In S4, the particle size of the polymer seed is 120 nm, and the PDI is less than 0.08; the particle size of the hard core microspheres is 170-220 nm, and the PDI is less than 0.08; the particle size of the hard core soft shell structured photonic crystal microspheres is 200-300 nm, and the PDI is less than 0.

08.

2. The method according to claim 1, characterized in that The mass ratio of ethyl acrylate to butyl acrylate in the monomer for the soft shell is (19-20): (0-1).

3. The method according to claim 1, characterized in that The mass ratio of methyl methacrylate to butyl acrylate in the soft shell monomer is 1:

3.

4. The method according to claim 1, wherein The TPU / DMF spinning solution concentration is 15-25 wt.%.

5. The method according to claim 1, wherein The TPU / DMF spinning solution concentration is 20-22.5 wt.%.

6. The method according to claim 1, characterized in that The concentration of TPU / DMF spinning solution is: the conductive material in step S2 is one or more of conductive carbon black, graphene oxide, reduced graphene oxide, carbon nanotubes, MXene, silver nanowires, and silver nanoparticles.

7. The method according to claim 1, wherein The concentration of the conductive material DMF dispersion in S2 is 10-40 mg / mL.

8. The method according to claim 1, wherein The concentration of the conductive material DMF dispersion in S2 is 30-40 mg / mL.

9. The method according to claim 1, characterized in that In S3, the TPU / DMF solution in steps S1 and S2 and the conductive material DMF dispersion are mixed in a ratio of 1:1, loaded into a syringe and then wet-spun to prepare a TPU electrical sensing fiber. The coagulation bath is a mixed solution of isopropyl alcohol, water and calcium chloride.

10. The method according to claim 1, characterized in that In step S4 , the mass ratio of the (a) monomer for the hard core to the (b) monomer for the hard core is 1:(1-2).

11. The method according to claim 1, wherein In step S4, the emulsifier used for emulsification is one of sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate.

12. The method according to claim 1, wherein In step S4, the crosslinking agent is one or more of divinylbenzene, allyl methacrylate, and isoprene; the amount of the crosslinking agent in (a) or (b) relative to the hard core monomer in this step is 10-14 wt.%; and the amount of the crosslinking agent in (c) relative to the soft shell monomer in this step is 0.2-1.0 wt.%.

13. The method according to claim 1, wherein In step S4, the initiator is one or more of ammonium persulfate, potassium persulfate, and sodium persulfate; and the ratio of the initiator to the monomer in (a), (b), or (c) is 0.5-1 wt.%.

14. The method according to claim 1, wherein The dipping time in S5 is 10-60 s, and the drying time is 10-60 s.

15. An optoelectronic dual-mode stress-strain sensing fiber prepared by the method according to any one of claims 1 to 14.

16. Use of the optoelectronic dual-mode stress-strain sensing fiber according to claim 15 in the preparation of optoelectronic signal sensing components.

17. Use of the optoelectronic dual-mode stress-strain sensing fiber according to claim 15 in the construction of a human joint motion monitoring product.

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