Preparation method and application of photoelectric collaborative flexible optical fiber sensor

Abstract

The invention discloses a preparation method and application of a photoelectric collaborative flexible optical fiber, and belongs to the technical field of multifunctional flexible optical fiber preparation. Conductive fibers are prepared through a wet spinning / melt co-extrusion spinning process, the conductive fibers are placed in a hollow part of a hollow cladding preform of an optical fiber, and the photoelectric synergistic flexible optical fiber sensor is obtained through synchronous hot wire drawing. According to the invention, the flexible electrode is combined with the transparent high polymer material with good light guide performance to form the photoelectric cooperative sensing flexible optical fiber sensor with both light response and electric response, and the unique optical fiber structure not only achieves the photoelectric cooperative sensing function, but also plays a role in packaging the flexible electrode, so that the durability of the optical fiber sensor is higher. The fiber has excellent performances of flexibility, fatigue resistance and the like, can be used as optical fiber sensing equipment for monitoring human joint movement, and has huge application potential in the fields of optical fiber communication, sensing detection, biomedical treatment and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of multifunctional flexible optical fibers, and particularly relates to a preparation method and application of an optoelectronic collaborative flexible optical fiber sensor. Background Art

[0002] With the development of science and technology, portable wearable devices play an increasingly important role in the current era. One-dimensional flexible optical fibers occupy an important position in the field of portable wearables. The characteristic of flexible optical fibers is that they produce deformation responses under the action of external physical, chemical and other stimuli and bring corresponding functions, with advantages such as fast response speed, wide response range, and high sensitivity. Flexible optical fiber sensors have great application prospects in the fields of flexible driving and sensing. Most flexible optical fibers only focus on the transmission of a single optical signal, while multifunctional flexible optical fibers, based on ordinary flexible optical fibers, have the ability of multi-signal collaborative sensing and have received extensive attention, making them excellent candidate materials for human-computer interaction, artificial skin, soft robots and biomedical engineering.

[0003] Compared with conventional stretchable optical fibers, a main advantage of optoelectronic collaborative flexible optical fibers is that by simultaneously monitoring the changes in the optical signal and electrical signal of the sensor, more accurate sensing signals can be obtained and there are broader application scenarios. However, there is currently no relevant report on the preparation of optoelectronic collaborative optical fiber sensors by combining wet spinning or melt spinning electrodes with plastic flexible optical fibers. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of an optoelectronic collaborative flexible optical fiber sensor. The preparation process is simple, and the prepared optoelectronic collaborative flexible optical fiber sensor can synchronously transmit optical signals and electrical signals, and a visual interactive sensing device can be prepared to monitor human joint movements.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides a preparation method of an optoelectronic collaborative flexible optical fiber sensor, including the following steps:

[0007] Step 1: Place a polytetrafluoroethylene rod along the axial center of the plastic sleeve of the optical fiber preform mold, pour the thermoplastic elastomer into the plastic sleeve, heat the mold until the thermoplastic elastomer is completely melted, and after cooling and shaping, remove the mold and the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0008] Step 2: Add carbon black to the thermoplastic elastomer and form shaped fibers through wet spinning or melt spinning for standby;

[0009] Step 3: Place the hollow cladding preform in the heating furnace of the drawing tower, vertically feed a single shaped fiber obtained in Step 2 into the hollow part of the hollow cladding preform, and perform synchronous hot drawing. After cooling, the finished product is obtained.

[0010] Further, the thermoplastic elastomer is one of TPU (polyurethane), TPS (styrene-based thermoplastic elastomer, such as SEBS, SBS), EVA (ethylene-vinyl acetate copolymer), and TPO (polyolefin-based thermoplastic elastomer).

[0011] Further, the diameter of the polytetrafluoroethylene rod is 2 - 10 mm.

[0012] Further, the plastic sleeve in the optical fiber preform mold is made of Teflon and has a diameter of 10 - 40 mm.

[0013] Further, in step 1, the temperature for heating the mold is 80 - 240 °C. When the thermoplastic elastomer is EVA, the heating temperature is 80 - 120 °C; when the thermoplastic elastomer is TPU, the heating temperature is 120 - 180 °C; when the thermoplastic elastomer is TPS, the heating temperature is 160 - 200 °C; when the thermoplastic elastomer is TPO, the heating temperature is 180 - 240 °C.

[0014] Further, in step 2, the preparation steps of the wet spinning are as follows:

[0015] The thermoplastic elastomer and carbon black are dissolved in an organic solvent, and stirred evenly to obtain a spinning solution. The mass ratio of carbon black to thermoplastic elastomer in the spinning solution is 5 - 25:100. After wet spinning, the formed fibers are taken out from the coagulation bath and dried for standby;

[0016] The preparation steps of the melt spinning are as follows:

[0017] Carbon black and the thermoplastic elastomer are mixed in a mass ratio of 5 - 25:100 and placed in a melt extruder. They are melted and extruded for spinning at 120 - 220 °C to obtain formed fibers, which are cooled for standby.

[0018] When the thermoplastic elastomer material is TPU, the melt extrusion temperature is controlled at 120 - 200 °C; when the thermoplastic elastomer material is TPS, the melt extrusion temperature is controlled at 160 - 220 °C; when the thermoplastic elastomer is EVA, the melt extrusion temperature is controlled at 100 - 160 °C; when the thermoplastic elastomer material is TPO, the melt extrusion temperature is controlled at 150 - 200 °C.

[0019] Further, the solid content of the spinning solution is 10 - 40%.

[0020] Furthermore, the organic solvent is one of toluene, N,N-dimethylformamide, chloroform, dichloromethane, acetone, cyclohexane and tetrahydrofuran. N,N-dimethylformamide is preferred, as N,N-dimethylformamide has good solubility, can dissolve thermoplastic elastomer, disperse carbon black, form a uniform spinning solution, and help improve the success rate of wet spinning.

[0021] Furthermore, the coagulation bath is one of deionized water and ethanol. The coagulation bath can be miscible with the organic solvent so as to exchange the organic solvent in the spun fiber, which is beneficial to the forming and annealing of the spun fiber.

[0022] Furthermore, the single fiber diameter of the molded fiber is 50-500 μm.

[0023] Further, the hot drawing temperature of the drawing tower heating furnace is 80-220° C. When the thermoplastic elastomer in step 1 is EVA, the hot drawing temperature is set to 80-120° C., when the thermoplastic elastomer is TPU, the hot drawing temperature is set to 100-160° C., when the thermoplastic elastomer is TPS, the hot drawing temperature is set to 160-200° C., and when the thermoplastic elastomer is TPO, the hot drawing temperature is set to 180-220° C.

[0024] Furthermore, the diameter of the finished optical fiber is 200um to 2000um.

[0025] The present invention also provides an application of a photoelectric cooperative flexible optical fiber sensor, wherein the photoelectric cooperative flexible optical fiber sensor prepared by the preparation method described above is used to prepare a visual interactive sensing device to monitor human joint movements. The human joint movements include neck joints, elbow joints, finger joints, and knee joints.

[0026] The prepared optoelectronic cooperative flexible optical fiber sensor has unique mechanical response characteristics, such as dual sensing of optical and electrical signals when stretched, which is due to the coordinated stretching of the flexible optical fiber and the wet-spun elastic electrode contained in it. This unique optical fiber structure not only achieves the function of optoelectronic cooperative sensing, but also acts as a package for the flexible electrode, making the optical fiber sensor more durable.

[0027] This technical solution successfully combines flexible electrodes with thermoplastic elastomers with good light conductivity to form a photoelectric cooperative sensing flexible optical fiber sensor with both light response and electrical response, which is suitable for various advanced application scenarios such as wearable technology, soft robots and human-computer interaction interfaces.

[0028] Beneficial effects of the present invention:

[0029] (1) The preparation method of the optoelectronic collaborative flexible optical fiber sensor provided by the present invention is simple, and its mechanical collaborative tensile strain can reach 520%, and the tensile fracture rate of the optical fiber cladding can reach 860%.

[0030] (2) When the optoelectronic collaborative flexible optical fiber sensor prepared by the present invention is mechanically stretched, its light intensity signal attenuates while the voltage signal increases, and the entire change process is reversible.

[0031] (3) The optoelectronic collaborative flexible optical fiber sensor prepared by the present invention has unique advantages in detecting bending and stretching. When the wrist bends inward, the optical fiber bends and stretches, and at this time, both the light intensity and the resistance change. When the wrist bends outward, the optical fiber bends but does not stretch, and at this time, only the light intensity signal changes while the resistance signal remains unchanged, realizing the precise detection of wrist movements.

[0032] (4) The optoelectronic collaborative flexible optical fiber sensor prepared by the present invention has excellent properties such as flexibility and fatigue resistance. As an optical fiber sensing device for monitoring human joint movements, it has great application potential in the fields of optical fiber communication, sensing detection, biological medicine, etc. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0034] Figure 1 is a schematic structural diagram of the optical fiber preform mold and the polytetrafluoroethylene rod in the embodiment of the present invention;

[0035] In the figure: 1 is the upper cap; 2 is the lower cap; 3 is the plastic sleeve; 4 is the polytetrafluoroethylene rod.

[0036] Figure 2 is the stress-strain curve of the optoelectronic collaborative flexible optical fiber sensor prepared in Example 1 of the present invention.

[0037] Figure 3 is the resistance change diagram during the 2000-time stretching and recovery process of the optoelectronic collaborative flexible optical fiber sensor prepared in Example 1 of the present invention.

[0038] Figure 4 is the change diagram of the resistance signal and the light intensity signal of the optoelectronic collaborative flexible optical fiber sensor prepared in Example 1 of the present invention under different stretching rates.

[0039] Figure 5 is the change diagram of the resistance signal and the light intensity signal of the optoelectronic collaborative flexible optical fiber sensor prepared in Example 1 of the present invention on the wrist;

[0040] In the figure: the left figure shows the wrist bending inward; the right figure shows the wrist bending outward.

[0041] Figure 6It is a graph showing the change in optical power output loss of the flexible fiber optic sensor prepared in Comparative Example 1 of the present invention under direct tensile bending conditions;

[0042] In the figure: The left figure shows the change in optical power output loss caused by the change in tensile stress; the right figure shows the change in optical power output loss corresponding to different bending angles.

[0043] Figure 7 It is a graph showing the change in optical power output loss of the flexible fiber optic sensor prepared in Comparative Example 1 of the present invention on the wrist;

[0044] In the figure: The left figure shows the change in optical power output loss caused by the wrist bending inward; the right figure shows the change in optical power output loss caused by the wrist bending outward. Specific embodiments

[0045] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0046] Embodiment 1

[0047] A preparation method of an optoelectronic collaborative flexible fiber optic sensor includes the following steps:

[0048] Step 1: Place a polytetrafluoroethylene rod (the diameter of the polytetrafluoroethylene rod is 5 mm, and the diameter of the plastic sleeve is 20 mm) along the axial center of the plastic sleeve of the fiber preform mold. Its structural schematic diagram is as Figure 1 shown. Pour 70 g of EVA masterbatch into the plastic sleeve (made of polytetrafluoroethylene), then place the mold in a vacuum drying oven and heat it to 90 °C, and keep it at a constant temperature until the EVA masterbatch is completely melted into a whole. Peel off the mold and extract the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0049] Step 2: Preparation of the flexible wet spinning electrode: Put 2 g of TPU masterbatch and 0.24 g of conductive carbon black into N,N-dimethylformamide (DMF) solvent, ultrasonically disperse and stir evenly to form a spinning solution with a solid content of 30%. After wet spinning, take out the spun fiber from the coagulation bath (ethanol), dry it and set it aside. The diameter of a single fiber is 200 μm;

[0050] Step 3: Place the EVA hollow cladding preform in the heating furnace of the wire drawing tower, set the hot wire drawing temperature to 80 °C, and while hot wire drawing, vertically feed the formed fiber obtained in Step 2 into the hollow part of the hollow cladding preform one by one to achieve synchronous wire drawing, thus obtaining an optoelectronic collaborative flexible fiber optic sensor. The sample is marked as S1, the diameter of S1 is 800 um, the ellipticity of the fiber is detected to be 0.0084, and the conductivity is 29.7 S / m.

[0051] Perform mechanical property tests on the prepared optoelectronic collaborative flexible fiber optic sensor S1, such as Figure 2 shown. The optoelectronic collaborative flexible fiber optic sensor shows high tensile properties. The co-stretching strain of the fiber optic sensor can reach 520%, and the cladding stretching can reach 860%. This high ductility enables them to be integrated into smart clothing or skin patches for health monitoring, further broadening the application of optoelectronic collaborative flexible fiber optic sensor devices.

[0052] Test the prepared optoelectronic collaborative flexible fiber optic sensor S1, and it shows the stability of the electrical signal output during the stretching and recovery process, such as Figure 3 shown. During mechanical stretching, its resistance change rate changes from zero to 40%. The whole process is completely reversible, and there is no obvious delay between mechanical relaxation and resistance recovery. Moreover, no obvious attenuation is observed during multiple stretching and release cycles.

[0053] Perform sensing performance tests on the prepared optoelectronic collaborative flexible fiber optic sensor S1. The test method is as follows:

[0054] Perform strain sensing performance tests on the flexible fiber optic sensor device. Use an LED red light source, a multimeter, and a 200 - 1000 nm ocean spectrometer. The test results of the optoelectronic collaborative flexible fiber optic sensor in Example 1 are as Figure 4 shown. During the stretching process of the optoelectronic collaborative flexible fiber optic sensor, as the stretching rate increases, the resistance increases while the light intensity decreases. It can be clearly observed from the laser spectrum that when the stretching rate is 0%, the resistance is 0.1 ΜΩ and the light intensity is 1250 cd. As the stretching further increases, the light intensity significantly decreases. When the stretching rate is 200%, the resistance changes to 4 ΜΩ and the light intensity changes to 250 cd. Therefore, optoelectronic collaborative sensing of optical signals and electrical signals is achieved by stretching the optoelectronic collaborative flexible fiber optic sensor device.

[0055] Use the designed optoelectronic collaborative flexible fiber optic sensor as a visual interactive sensing device for real-time monitoring of human joint movements. As Figure 5 ( Figure 5As shown in the left figure in (), when the optoelectronic collaborative flexible fiber optic sensor prepared in Example 1 is attached to the back of the human wrist, as the bending angle of the wrist towards the inside increases, changes in electrical signals and optical signals can be observed. When the wrist changes from the extended state to the bent state, the resistance signal of the flexible fiber optic sensor increases from small to large, the optical loss increases from small to large, and the corresponding optical intensity signal decreases from large to small. And as the bending returns to the extended state, the resistance signal and optical intensity signal of the flexible fiber optic sensor return to their original states. In particular, when bending outward when attached to the back of the human wrist, as Figure 5 shown in the right figure in (), the flexible fiber optic sensor can monitor the movement of the joint through different changes in the resistance signal and optical intensity signal. At this time, the optical fiber is bent but not stretched, and only the optical intensity signal changes while the resistance signal remains unchanged.

[0056] Example 2

[0057] The difference from Example 1 is only that the wet spinning process in Step 2 is replaced by melt spinning. The specific steps are as follows:

[0058] Step 1: Place a polytetrafluoroethylene rod (the diameter of the polytetrafluoroethylene rod is 5 mm and the diameter of the plastic sleeve is 20 mm) along the axial center of the plastic sleeve of the fiber preform mold. Its structural schematic diagram is as Figure 1 shown. Pour 70 g of EVA masterbatch into the plastic sleeve (made of polytetrafluoroethylene), then place the mold in a vacuum drying oven and heat it to 90 °C, keep it at a constant temperature until the EVA masterbatch is completely melted into a whole, peel off the mold and extract the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0059] Step 2: Preparation of the flexible melt-spun electrode: Mix 2 g of TPU masterbatch and 0.24 g of conductive carbon black evenly and place them in a melt extruder. Melt and extrude the spinning at 120 - 200 °C to obtain formed fibers, cool and set aside. The diameter of a single fiber is 200 μm;

[0060] Step 3: Place the EVA hollow cladding preform in the heating furnace of the drawing tower, set the hot drawing temperature to 80 °C, and vertically feed the formed fibers obtained in Step 2 into the hollow part of the EVA hollow cladding preform one by one while hot drawing to achieve synchronous drawing, obtaining an optoelectronic collaborative flexible fiber optic sensor. The sample is marked as S2, the diameter of S2 is 800 um, the ellipticity of the fiber is detected to be 0.0011, and the conductivity is 5.12 S / m.

[0061] Perform mechanical property tests on the prepared optoelectronic collaborative flexible fiber optic sensor S2. The test method is the same as that in Example 1. The co-stretching strain of its fiber optic sensor can reach 430%, and the cladding stretching can reach 800%.

[0062] Example 3

[0063] The difference from Example 1 is only that the EVA masterbatch in Step 1 is replaced with an SEBS masterbatch, and the diameter of a single fiber after drying the formed fiber is 150 μm.

[0064] A preparation method of an optoelectronic collaborative flexible optical fiber sensor includes the following steps:

[0065] Step 1: Place a polytetrafluoroethylene rod (with a diameter of 5 mm for the polytetrafluoroethylene rod and a diameter of 20 mm for the plastic sleeve) along the axial center of the plastic sleeve of the optical fiber preform mold. Its structural schematic diagram is as Figure 1 shown. Pour 70 g of SEBS masterbatch into the plastic sleeve (made of polytetrafluoroethylene), then place the mold in a vacuum drying oven and heat it to 200 °C, keep it at a constant temperature until the SEBS masterbatch is completely melted into a whole, peel off the mold and extract the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0066] Step 2: Preparation of a flexible wet-spun electrode: Put 2 g of TPU masterbatch and 0.24 g of conductive carbon black into N,N-dimethylformamide (DMF) solvent, ultrasonically disperse and stir evenly to form a spinning solution with a solid content of 30%. After wet spinning, take out the spun fiber from the coagulation bath (ethanol), air dry and set aside. The diameter of a single fiber is 150 μm;

[0067] Step 3: Place the SEBS hollow cladding preform in the heating furnace of the drawing tower, set the hot drawing temperature to 180 °C, and while hot drawing, vertically feed a single formed fiber obtained in Step 2 into the hollow part of the SEBS hollow cladding preform to achieve synchronous drawing, obtaining an optoelectronic collaborative flexible optical fiber sensor. The sample is marked as S3. The ellipticity of the optical fiber is detected to be 0.0086, the diameter of S3 is 600 μm, and the conductivity is 30.02 S / m.

[0068] Perform a mechanical property test on the prepared optoelectronic collaborative flexible optical fiber sensor S3. The test method is the same as that in Example 1. The co-tensile strain of the optical fiber sensor can reach 500%, and the cladding tensile can reach 1200%.

[0069] Example 4

[0070] The difference from Example 1 is only that the TPU masterbatch in Step 2 is replaced with an SEBS masterbatch.

[0071] A preparation method of an optoelectronic collaborative flexible optical fiber sensor includes the following steps:

[0072] Step 1: Place a polytetrafluoroethylene rod (with a diameter of 5 mm for the polytetrafluoroethylene rod and a diameter of 20 mm for the plastic sleeve) along the axial center of the plastic sleeve of the optical fiber preform mold. Its structural schematic diagram is as Figure 1As shown, pour 70 g of EVA masterbatch into a plastic sleeve (made of polytetrafluoroethylene), then place the mold in a vacuum drying oven and heat it to 90 °C. Keep it at a constant temperature until the EVA masterbatch is completely melted into a whole. Peel off the mold and extract the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0073] Step 2: Preparation of a flexible wet-spun electrode: Put 2 g of SEBS masterbatch and 0.24 g of conductive carbon black into tetrahydrofuran (THF) solvent and disperse them by ultrasonic wave, stir evenly to form a spinning solution with a solid content of 30%. After wet spinning, take out the spun fiber from the coagulation bath (ethanol), dry it and set aside. The diameter of a single fiber is 200 μm;

[0074] Step 3: Place the EVA hollow cladding preform in the heating furnace of a drawing tower, set the hot drawing temperature to 80 °C. While hot drawing, vertically feed the fiber obtained in Step 2 into the hollow part of the EVA hollow cladding preform one by one to achieve synchronous drawing, and obtain an optoelectronic collaborative flexible fiber optic sensor. The sample is marked as S4, the diameter of S4 is 800 μm, and the ellipticity of the fiber is detected to be 0.0064, and the conductivity is 30.86 S / m.

[0075] Perform mechanical property tests on the prepared optoelectronic collaborative flexible fiber optic sensor S4. The test method is the same as that in Example 1. The co-stretching strain of the fiber optic sensor can reach 500%, and the cladding stretching can reach 800%.

[0076] Example 5

[0077] The difference from Example 4 is only that the EVA masterbatch in Step 1 is replaced with a TPU masterbatch.

[0078] A preparation method of an optoelectronic collaborative flexible fiber optic sensor includes the following steps:

[0079] Step 1: Place a polytetrafluoroethylene rod (the diameter of the polytetrafluoroethylene rod is 5 mm and the diameter of the plastic sleeve is 20 mm) along the axial center of the plastic sleeve of the fiber preform mold. Its structural schematic diagram is as Figure 1 shown. Pour 70 g of TPU masterbatch into the plastic sleeve (made of polytetrafluoroethylene), then place the mold in a vacuum drying oven and heat it to 120 °C. Keep it at a constant temperature until the TPU masterbatch is completely melted into a whole. Peel off the mold and extract the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0080] Step 2: Preparation of a flexible wet-spun electrode: Put 2 g of SEBS masterbatch and 0.24 g of conductive carbon black into tetrahydrofuran (THF) solvent and disperse them by ultrasonic wave, stir evenly to form a spinning solution with a solid content of 30%. After wet spinning, take out the spun fiber from the coagulation bath (ethanol), dry it and set aside. The diameter of a single fiber is 200 μm;

[0081] Step 3: Place the TPU hollow cladding preform in the heating furnace of the drawing tower, set the hot drawing temperature to 100 °C, and while hot drawing, vertically feed the single spinning fiber obtained in Step 2 into the hollow part of the hollow cladding preform to achieve synchronous drawing, obtaining an optoelectronic collaborative flexible fiber optic sensor. The sample is marked as S5, the diameter of S5 is 800 um, the measured fiber ellipticity is 0.008, and the conductivity is 29.69 S / m.

[0082] Perform mechanical property tests on the prepared optoelectronic collaborative flexible fiber optic sensor S5. The test method is the same as that in Example 1. The co-drawing strain of the fiber optic sensor can reach 630%, and the cladding drawing can reach 800%.

[0083] Comparative Example 1

[0084] Compared with Example 1, the wet spinning fiber is not added to the preform in this comparative example. The specific preparation steps are as follows:

[0085] Step 1: Pour 70 g of EVA masterbatch into the plastic sleeve (the diameter of the plastic sleeve is 20 mm, made of polytetrafluoroethylene) of the fiber optic preform mold, then place the mold in a vacuum drying oven and heat it to 90 °C, keep it at a constant temperature until the EVA masterbatch is completely melted into a whole, and peel off the mold to obtain the preform;

[0086] Step 2: Place the EVA preform in the heating furnace of the drawing tower, set the hot drawing temperature to 80 °C, complete the drawing, obtaining a flexible fiber optic sensor. The sample is marked as S6, the diameter of S6 is 800 um, the measured fiber ellipticity is 0.0032, and S6 does not have electrical conductivity.

[0087] Perform mechanical property tests on the prepared flexible fiber optic sensor S6. The test method is the same as that in Example 1. The drawing strain of the fiber optic sensor can reach 850%.

[0088] Perform strain sensing performance tests on the flexible fiber optic sensor device, using an LED red light source, a multimeter, and a 200 - 1000 nm marine spectrometer. Figure 6 This is the direct tensile bending test result of S6. The left figure shows the change in the optical power output loss caused by the change in tensile stress, and the right figure shows the change in the optical power output loss corresponding to different bending angles. It can only monitor the change in the optical signal intensity. Figure 7 This is the change in the optical signal and electrical signal when S6 is attached to the human wrist and makes a bending movement. Compared with Example 1, the fiber optic sensor prepared in Comparative Example 1 does not have the function of optoelectronic collaborative sensing. The bending movements on the inner and outer sides of the human wrist cannot be judged by the two signals and cannot be accurately distinguished.

[0089] Comparative Example 2

[0090] Compared with Example 1, in this comparative example, the mass ratio of carbon black to TPU masterbatch in Step 2 is 4:100.

[0091] A preparation method of an optoelectronic collaborative flexible optical fiber sensor includes the following steps:

[0092] Step 1: Place a polytetrafluoroethylene rod (with a diameter of 5 mm for the polytetrafluoroethylene rod and a diameter of 20 mm for the plastic sleeve) along the axial center of the plastic sleeve of the optical fiber preform mold. Its structural schematic diagram is as Figure 1 shown. Pour 70 g of EVA masterbatch into the plastic sleeve (made of polytetrafluoroethylene), then place the mold in a vacuum drying oven and heat it to 90 °C, and keep it at a constant temperature until the EVA masterbatch is completely melted into a whole. Peel off the mold and extract the polytetrafluoroethylene rod to obtain a hollow cladding preform;

[0093] Step 2: Preparation of the flexible wet-spun electrode: Put 2 g of TPU masterbatch and 0.08 g of conductive carbon black into N,N-dimethylformamide (DMF) solvent, ultrasonically disperse them, and stir evenly to form a spinning solution with a solid content of 30%. After wet spinning, take out the spun fiber from the coagulation bath (ethanol), dry it and set aside. The diameter of a single fiber is 200 μm;

[0094] Step 3: Place the EVA hollow cladding preform in the heating furnace of the drawing tower, set the hot drawing temperature to 80 °C, and while hot drawing, vertically feed the spun fiber obtained in Step 2 into the hollow part of the EVA hollow cladding preform one by one to achieve synchronous drawing, and obtain an optoelectronic collaborative flexible optical fiber sensor. The sample is marked as S7, the diameter of S7 is 800 μm, and the ellipticity of the optical fiber is detected to be 0.0211, and the conductivity is 0.0017 S / m.

[0095] Perform mechanical property tests on the prepared optoelectronic collaborative flexible optical fiber sensor S7. The test method is the same as that in Example 1. The co-stretching strain of the optical fiber sensor can reach 600%, and the cladding stretching can reach 800%.

[0096] When the carbon black addition amount of the intermediate fiber in Comparative Example 2 is less, its conductivity will decrease significantly, it is not sensitive to the signal capture of fine movements, and the sensitivity is not as good as that in Example 1.

[0097] The optoelectronic collaborative flexible optical fiber sensor of this technical solution has excellent electrical properties, excellent mechanical properties and a wide range of optoelectronic collaborative sensing properties. These results show that the invented flexible optical fiber sensor can exhibit multi-dimensional sensing properties during the dynamic activities of human joints and can be used as a biomechanical monitoring device during the movement of human joints.

[0098] It should be noted that, in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0099] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a photoelectric coordinated flexible optical fiber sensor, characterized in that: The steps include: Step 1: a polytetrafluoroethylene rod is placed along the axial center of the plastic sleeve of the optical fiber preform mold, a thermoplastic elastomer is poured into the plastic sleeve, the mold is heated until the thermoplastic elastomer is completely melted, and after cooling and molding, the mold and the polytetrafluoroethylene rod are removed to obtain a hollow cladding preform; Step 2, adding carbon black to the thermoplastic elastomer to form a molded fiber through wet spinning or melt spinning, and then setting aside; Step 3: The hollow cladding preform is placed in a heating furnace of a drawing tower, and a single shaped fiber obtained in step 2 is vertically fed into the hollow part of the hollow cladding preform, and is simultaneously hot-drawn, and a finished product is obtained after cooling.

2. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: The thermoplastic elastomer is one of TPU, TPS, EVA and TPO.

3. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: The diameter of the polytetrafluoroethylene rod is 2-10 mm; The plastic sleeve in the optical fiber preform mold is made of Teflon and has a diameter of 10-40 mm.

4. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: In step 1, the mold is heated to a temperature of 80-240°C.

5. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: In step 2, the preparation steps of the wet spinning are as follows: Thermoplastic elastomer and carbon black are dissolved in an organic solvent and stirred to obtain a spinning solution, wherein the mass ratio of carbon black to thermoplastic elastomer in the spinning solution is 5-25:

100. After wet spinning, the formed fiber is taken out from the coagulation bath and dried for later use. The preparation steps of the melt spinning are as follows: The carbon black and the thermoplastic elastomer are mixed in a mass ratio of 5-25:100 and placed in a melt extruder, melted and extruded at 120-220° C. to obtain a molded fiber, which is then cooled for later use.

6. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 5, characterized in that: The solid content of the spinning solution is 10-40%.

7. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: The single fiber diameter of the shaped fiber is 50-500 μm.

8. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: The hot drawing temperature of the drawing tower heating furnace is 80-220°C.

9. The method for preparing a photoelectric cooperative flexible optical fiber sensor according to claim 1, characterized in that: The optical fiber diameter of the finished product is 200um to 2000um.

10. An application of a photoelectric coordinated flexible optical fiber sensor, characterized in that: The optoelectronic cooperative flexible optical fiber sensor prepared by the preparation method as described in any one of claims 1 to 9 is used to prepare a visual interactive sensing device to monitor human joint movements.

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