A flexible multifunctional sensor, system and fabrication method

Abstract

This invention discloses a flexible multifunctional sensor, system, and fabrication method, comprising a triboelectric nanogenerator, a flexible capacitive pressure sensing layer, and a bottom electrode arranged sequentially from top to bottom. The flexible capacitive pressure sensing layer includes a microstructured ionogel membrane and an ionogel electrospun membrane attached together. The triboelectric nanogenerator includes a triboelectric layer and a double-sided electrode, with the triboelectric layer located on one side of the double-sided electrode and the other side of the double-sided electrode attached to the microstructured ionogel membrane. The bottom electrode is attached to the ionogel electrospun membrane. This enables simultaneous detection of the wearer's movements and the properties of objects in contact.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a flexible multifunctional sensor, system, and fabrication method. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Sensing components are indispensable in intelligent fields such as human-computer interaction. The trend towards flexible and miniaturized sensors is inevitable, and multi-sensing is becoming increasingly important.

[0004] As an important component of intelligent human-computer interaction, the flexibility and versatility of sensors are becoming increasingly prominent. However, traditional flexible sensors can only detect the wearer's actions or the properties of objects individually, and cannot simultaneously detect both actions and properties. Furthermore, wearing multiple sensors at the same time would be redundant, thus limiting the intelligence of human-computer interaction.

[0005] The inventors believe that how to simultaneously detect the wearer's movements and the properties of objects touched by the sensor, that is, to achieve diversified sensor detection, is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a flexible multifunctional sensor, system, and fabrication method that enables simultaneous detection of the wearer's movements and the properties of objects in contact, thereby diversifying sensor detection capabilities.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In the first aspect, a flexible multifunctional sensor is proposed, comprising a triboelectric nanogenerator, a flexible capacitive pressure sensing layer, and a bottom electrode arranged sequentially from the top to the bottom.

[0009] The flexible capacitive pressure sensing layer comprises a microstructured ionogel membrane and an ionogel electrospun membrane attached together.

[0010] The triboelectric nanogenerator includes a triboelectric layer and a double-sided electrode. The triboelectric layer is located on one of the double-sided electrodes, and the other electrode is attached to a microstructured ionogel membrane.

[0011] The bottom electrode is attached to the ion gel electrospun membrane.

[0012] Secondly, a method for fabricating a flexible multifunctional sensor, as proposed in the first aspect, is presented, including:

[0013] Ion gel electrospun membranes, microstructured ion gel membranes, and double-sided electrodes were prepared respectively.

[0014] Microstructured ionogel membranes and ionogel electrospun membranes are bonded together to form a flexible capacitive pressure sensing layer.

[0015] A triboelectric nanogenerator is formed by spin-coating a triboelectric layer onto one of the electrodes of a double-sided electrode.

[0016] Triboelectric nanogenerators are attached to microstructured ionogel membranes.

[0017] The bottom electrode is attached to the ion gel electrospun membrane.

[0018] Thirdly, a human-computer interaction system based on a flexible multifunctional sensor is proposed, including:

[0019] The first aspect proposes a flexible multifunctional sensor for attaching to the joints and fingertips of the wearer's hand;

[0020] The control system is used to determine the wearer's movements and the nature of the objects grasped based on signals detected by flexible multi-functional sensors at the joints and fingertips, and to control the virtual character to imitate the wearer's movements.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The sensor disclosed in this invention can detect the electropositive and electronegative properties of an object through a triboelectric nanogenerator, thereby detecting the properties of the object in contact. It can also detect the wearer's movements through a flexible capacitive pressure sensing layer. In other words, the sensor disclosed in this invention can simultaneously detect the wearer's movements and the properties of the object in contact, thus enabling diversified sensor detection.

[0023] 2. The microstructured ion gel membrane disclosed in this invention has multiple raised structures on one side attached to the double-sided electrode as microstructures on the microstructured ion gel membrane. These microstructures can reduce the contact area between the microstructured ion gel membrane and the double-sided electrode, thereby improving the sensitivity of the sensor detection.

[0024] 3. The ion gel electrospun membrane disclosed in this invention contains MXene material. MXene material is used as a dopant for conductive materials to form microcapacitors to improve the specific capacitance of the ion gel electrospun membrane, thereby improving the sensitivity of the flexible capacitive pressure sensor under high pressure and ultimately improving the sensing range.

[0025] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.

[0027] Figure 1 This is a schematic diagram of the overall structure of the sensor disclosed in Example 1;

[0028] Figure 2 This is a schematic diagram of the flexible capacitive pressure sensing layer disclosed in Example 1;

[0029] Figure 3(a) shows the stable response of the capacitance of the flexible capacitive pressure sensing material mentioned in Example 1 under different pressures;

[0030] Figure 3(b) shows the stable response of the capacitance of the flexible capacitive pressure sensing material mentioned in Example 1 under different pressures;

[0031] Figure 3(c) shows the stable response of the capacitance of the flexible capacitive pressure sensing material mentioned in Example 1 under different pressures;

[0032] Figure 4 The image shows a field emission scanning electron microscope (FESEM) image of the microstructured ionogel membrane disclosed in Example 1.

[0033] Figure 5 The flowchart of the sensor fabrication method disclosed in Example 1 is shown below;

[0034] Figure 6 The image shown is a field emission scanning electron microscope (FESEM) image of the ion gel electrospun membrane disclosed in Example 1.

[0035] Figure 7 The pressure sensing sensitivity curve of the sensor is disclosed in Example 1;

[0036] Figure 8 The stability diagram of the triboelectric nanogenerator disclosed in Example 1 is shown.

[0037] Figure 9 This is a schematic diagram of the flexible multifunctional sensor bonding disclosed in Example 3;

[0038] Figure 10 This is a human-computer interaction diagram of the system disclosed in Example 3;

[0039] Figure 11 The human-computer interaction flowchart of the system disclosed in Example 3 is shown below;

[0040] Figure 12 This is a diagram of the control system data transmission system disclosed in Example 3;

[0041] Figure 13 Figures showing the triboelectric properties of different materials;

[0042] Figure 14 This is a scanning electron microscope (FESEM) image of the foam structure of the triboelectric nanogenerator disclosed in Example 1.

[0043] The components are: 1. Friction layer, 2. First electrode, 3. Isolation layer, 4. Top electrode, 5. Microstructured ionogel membrane, 6. Ionogel electrospun membrane, 7. Bottom electrode, and 8. Substrate. Detailed Implementation

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0045] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0046] Example 1

[0047] In this embodiment, a flexible multifunctional sensor is disclosed, such as... Figure 1 As shown, it includes a triboelectric nanogenerator, a flexible capacitive pressure sensing layer and a bottom electrode 7 arranged sequentially from the top to the bottom. A substrate 8 is also arranged at the bottom of the bottom electrode 7.

[0048] The flexible capacitive pressure sensing layer comprises a microstructured ionogel membrane 5 and an ionogel electrospun membrane 6 attached together.

[0049] The triboelectric nanogenerator includes a triboelectric layer 1 and a double-sided electrode. The triboelectric layer 1 is located on one of the double-sided electrodes, and the other electrode is attached to a microstructured ionogel membrane 5.

[0050] The bottom electrode 7 is attached to the ion gel electrospinning membrane 6.

[0051] Preferably, the microstructured ionogel membrane 5 self-adheres onto the ionogel electrospun membrane 6.

[0052] The microstructured ionogel membrane 5 is prepared by using a mixed cellulose containing cellulose acetate and cellulose nitrate, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIM][TFSI]). The microstructured ionogel membrane 5 and the ionogel electrospun membrane 6 form a bilayer ionogel membrane. A large number of positive and negative charge ion pairs are distributed within the bilayer ionogel membrane. Unlike traditional capacitive pressure sensors, this bilayer ionogel membrane utilizes the electrical double-layer effect. When the bilayer ionogel membrane is subjected to pressure, due to the electrical double-layer effect, electrons on the electrodes attract ions of different charges on the bilayer ionogel membrane, thereby forming a large number of parallel small capacitors and increasing the specific capacitance of the sensor. Simultaneously, when the lower ionogel electrospun membrane 6 is subjected to pressure, air is expelled and the filaments become more compact, thereby increasing its dielectric constant and specific capacitance, thus improving the sensor's sensitivity.

[0053] To achieve a smaller initial capacitance and better ion charge aggregation effect, thereby improving the sensitivity of the flexible capacitive pressure sensing layer, multiple microstructures are formed on the side of the microstructured ion gel membrane 5 that is attached to the double-sided electrode. The microstructures are raised structures, which can be conical or other shaped raised structures. These microstructures are used to reduce the contact area between the microstructured ion gel membrane 5 and the top electrode in the initial state, so that there are only a few contact points between the microstructured ion gel membrane 5 and the top electrode in the initial state of the flexible capacitive pressure sensing layer, thus achieving a smaller initial capacitance. The initial state of the flexible capacitive pressure sensing layer is the state when it is not under pressure.

[0054] Furthermore, the ion gel electrospun membrane 6 of this embodiment also contains MXene material. Due to the microcapacitance effect formed by the monolithic MXene and the polymer material, the specific capacitance of the ion gel electrospun membrane is increased, thereby achieving the purpose of improving its sensitivity. By doping the ion gel electrospun membrane 6 with MXene material, the detection sensitivity of the sensor disclosed in this embodiment is improved.

[0055] The process for preparing microstructured ionogel membranes is as follows:

[0056] A microstructured ionogel membrane was formed by spin-coating a mixture of cellulose acetate and cellulose nitrate, along with 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([EMIM][TFSI]).

[0057] The ion gel electrospun membrane 6 includes multiple composite nanofibers. Each composite nanofiber is naturally attached to the side of the microstructure ion gel membrane 5 that does not have a microstructure, and each composite nanofiber contains MXene.

[0058] The composite nanofibers are preferably composite nanofibers formed from polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), [EMIM][TFSI], and MXene. The polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) can also be replaced by one of acrylonitrile-butadiene-styrene copolymer (ABS), polyurethane (PU), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), polyketide (PK), polylactic acid (PLA), silk fibroin, polylactic acid (PLLA), polyvinyl butyral (PVB), or polycaprolactone (PCL).

[0059] The flexible capacitive pressure sensing layer proposed in this embodiment exhibits different conductivity under different pressures, the principle of which is as follows: Figure 2 As shown, when the pressure is low, the electrode makes micro-contact with the upper microstructure ion gel film 5 of the flexible capacitor pressure sensing layer. Due to the electric double layer effect, electrons on the electrode and ions of different charges in the double-layer ion gel film attract each other, forming a large number of parallel microcapacitors, which improves the specific capacitance of the device and thus improves the capacitance of the device.

[0060] Under high pressure, more ion pairs are attracted by electrode electrons, thereby forming more parallel microcapacitors to improve the specific capacitance. At the same time, when the electric double layer effect reaches its limit under high pressure, the bottom ion gel electrospun film 6 is subjected to excessive pressure, the air in it is discharged and the filaments are more compact, thereby improving the specific capacitance and thus improving the sensitivity of the device under high pressure. The more compact filaments here include: (1) the spacing between the composite nano-limiters is reduced, the contact area between them is increased, and the number of filaments in contact with each other is increased; (2) the contact between the ion gel electrospun film 6 and the microstructure ion gel film is more compact.

[0061] The double-sided electrode includes a first electrode 2, an isolation layer 3 and a top electrode 4. The first electrode 2 and the top electrode 4 are respectively disposed on two sides of the isolation layer 3. A friction layer 1 is disposed on the first electrode, and the top electrode 4 is attached to the microstructure ion gel membrane 5.

[0062] In addition to silver, the first electrode 2 and the top electrode 4 can also be made of conductive tape, aluminum, or copper electrodes.

[0063] In order to make the overall integration of the sensor disclosed in this embodiment more compact and achieve the purpose of simultaneously collecting the wearer's movements and the properties of the objects touched, silver is magnetron sputtered on the front side of the isolation layer 3 of the triboelectric nanogenerator as the top electrode 4 of the flexible capacitive pressure sensing layer, and a first electrode 2 is magnetron sputtered on the back side of the isolation layer 3 as the electrode of the triboelectric nanogenerator. Then, a triboelectric layer 1 is spin-coated on one side of the first electrode 2 to form a completely integrated triboelectric nanogenerator.

[0064] The material of friction layer 1 is PVDF-HFP.

[0065] The isolation layer 3 is made of nylon vacuum filter membrane.

[0066] The two ends of the triboelectric nanogenerator are encapsulated by an encapsulation film, while the triboelectric layer is partially exposed. Specifically: Figure 1 Electrodes are led out from both ends of the friction layer 1 of the triboelectric nanogenerator and then encapsulated. During the encapsulation of the friction layer, a portion of the friction layer is left exposed.

[0067] The encapsulation film can be made of PDMS, polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), poly(vinylidene fluoride-trifluoroethylene-trifluorochloroethylene) (P(VDF-TrFE-CTFE)), polyurethane (PU), thermoplastic polyurethane elastomer rubber (TPU), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PET), polyimide (PI), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), or polyethylene naphthalate (PEN).

[0068] In addition, in order to enable the sensor disclosed in this embodiment to fit closely with gloves or skin, a flexible pressure sensor is prepared using a flexible pressure sensing material to achieve the purpose of monitoring hand movements at any time and to be better applied to intelligent human-computer interaction scenarios.

[0069] The fabrication process of a flexible multifunctional sensor disclosed in this embodiment is as follows:

[0070] Ion gel electrospun membranes, microstructured ion gel membranes, and double-sided electrodes were prepared respectively.

[0071] Microstructured ionogel membranes and ionogel electrospun membranes are bonded together to form a flexible capacitive pressure sensing layer.

[0072] A triboelectric nanogenerator is formed by spin-coating a triboelectric layer onto one of the electrodes of a double-sided electrode.

[0073] Triboelectric nanogenerators are attached to microstructured ionogel membranes.

[0074] The bottom electrode is attached to the ion gel electrospun membrane.

[0075] like Figure 5 As shown, the process for preparing ion-gel electrospun membranes is as follows:

[0076] 11) MXene was prepared by etching titanium aluminum carbide with LiF and hydrochloric acid;

[0077] 12) Ultrasonic dispersion and collection of single-layer few-layer MXene;

[0078] 13) Treat the monolayer few-layer Mxene with tetrabutylammonium hydroxide;

[0079] 14) Dissolve MXene treated with tetrabutylammonium hydroxide using N,N-dimethylamide as a solvent;

[0080] 15) Tetrahydrofuran and polymeric material are added to the solution obtained in 14) to prepare a spinning solution;

[0081] 16) Prepare an ion gel spinning solution by adding an ionic liquid to the spinning solution;

[0082] 17) Iongel electrospun membranes were prepared using iongel spinning solutions. The iongel electrospun membranes were visualized using a scanning electron microscope (SEM) as follows: Figure 6 As shown.

[0083] The process for preparing microstructured ionogel membranes is as follows:

[0084] 21) An ion gel solution was prepared by mixing acetone, polymer materials and ion liquid, and a microstructured copper template was prepared using a laser marking machine;

[0085] 22) An ion gel membrane was prepared by spin-coating the ion gel solution onto a microstructured copper template. The microstructured ion gel membrane was obtained using a field emission scanning electron microscope (SEM) image as follows: Figure 4 As shown.

[0086] The microstructured ionogel membrane and the ionogel electrospun membrane are naturally adhered together to form a flexible capacitive pressure sensing layer.

[0087] The process of fabricating a double-sided electrode is as follows:

[0088] 31) The first electrode is magnetron sputtered on the opposite side of the isolation layer;

[0089] 32) A top electrode is magnetron sputtered on the front side of the isolation layer to form a double-sided electrode.

[0090] The conditions for the magnetron sputtering electrode are as follows: a) reference pressure: 8.0×10⁻³ Pa - 2.0×10⁻³ Pa; b) working pressure: 0.8 Pa - 1.0 Pa; c) sputtering temperature: 20℃ - 30℃; d) gas flow rate: 40 sccm - 50 sccm; e) sputtering energy: 40 W - 50 W; f) pre-sputtering time: 60 s - 120 s; g) sputtering time: 10 min - 15 min.

[0091] Compared to common electrode materials such as graphene, silver nanowires, carbon nanotubes, and carbon black, magnetron sputtering deposition of silver is a low-cost, high-precision, and stable method that can achieve precise fabrication of interdigitated electrodes with a simple fabrication process.

[0092] The process of spin-coating a triboelectric layer onto the first electrode of a double-sided electrode to form a triboelectric nanogenerator is as follows:

[0093] 33) Prepare a spin-coating solution by mixing acetone and polymer materials;

[0094] 34) Spin-coating the solution onto one side of the first electrode to form a friction layer, thereby preparing a triboelectric nanogenerator.

[0095] The bottom electrode is attached to the ion gel electrospun membrane, the triboelectric nanogenerator is attached to the side of the microstructure ion gel membrane where the microstructure is set, and the two ends of the triboelectric nanogenerator are encapsulated to prepare a flexible multifunctional sensor disclosed in this embodiment.

[0096] The specific process for fabricating the flexible multifunctional sensor disclosed in this embodiment is as follows:

[0097] 11) Dissolve 1.0 g of lithium fluoride in 20 mL of pre-prepared hydrochloric acid (9 M), stir at room temperature for 30 min, slowly add 1.0 g of Ti3Alc2 powder, and etch at 35 °C for 48 h. Then wash with deionized water at 3500 rpm for 10 min, repeat this step until the pH of the supernatant is >5, and obtain the MXene solution.

[0098] 12) The MXene solution was sonicated in an ice-water bath until it turned dark green. After centrifugation at 8000 rpm for 1 h, the dark green supernatant was freeze-dried to prepare a single layer of MXene powder. The single layer of dark green supernatant obtained in this step is a stable colloid. After dilution, it exhibits the Tyndall effect and remains stable without precipitation.

[0099] 13) Take 50 mg of monolayer MXene powder, add 20 ml of tetrabutylammonium hydroxide and stir at room temperature for 24 h. Then wash with N,N-dimethylamide by centrifugation at 3500 rpm for 10 min. Repeat this step three times. This step treats the functional groups on the surface of MXene to improve its dispersibility in N,N-dimethylamide.

[0100] 14) Collect the MXene precipitate from 13) by centrifugation and add 4.4 g of N,N-dimethylamide. Disperse the MXene / N,N-dimethylamide solution by sonication for 30 min until it turns yellow-green.

[0101] 15) Add 4.4 g tetrahydrofuran and 1.2 g polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) to MXene / N,N-dimethylamide solution and stir at 70 °C for 1 h to prepare a polymer spinning solution.

[0102] 16) Add 120 mg of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt ([EMIM][TFSI]) ionic liquid to the spinning solution of the polymer material in 15), and stir at room temperature for 30 min to prepare an ion gel electrospinning solution. The resulting solution has a concentration of 0.5 wt% MXene, 1.2 wt% [EMIM][TFSI], and 12 wt% PVDF-HFP.

[0103] 17) The ion-gel electrospinning solution from 16) was electrospinned at 25 kV for 5 hours. The distance between the electrode generating electrostatics and the collecting paper for collecting the composite nanofibers was 15 cm, the syringe flow rate was 0.8 mL / h, and the collecting cylinder rotation speed was 200 r / min. Comparison showed that this concentration ratio resulted in more uniform nanofibers with a smaller average diameter. Field emission scanning electron microscopy (FESEM) images of the electrospun nanofibers are shown below. Figure 6 As shown.

[0104] 21) Add 1g of mixed cellulose (45wt% cellulose acetate, 55wt% cellulose nitrate) to 20mg of acetone and stir thoroughly at 70℃ for 1h. Add 1g of [EMIM][TFSI] to the above solution and stir thoroughly at room temperature for 30min to crosslink and prepare an ionomer gel solution. The solution should not be left idle for too long after stirring, as the crosslinking of the two materials will cause natural solidification if left idle for too long. The resulting solution concentration is 5wt% mixed cellulose and 5wt% [EMIM][TFSI]. Simultaneously, a microstructured copper template with a bottom diameter of 100μm was prepared using a cold laser marking machine.

[0105] 22) The ionogel solution obtained in 21) was spin-coated onto a microstructured copper template at 450 rpm. To ensure better adhesion between the solution and the template structure, the spin-coated template was vacuum-de-saturated for 5 minutes, allowed to air dry, and then demolded to obtain the microstructured ionogel membrane. The microstructured field emission electron microscopy (FESEM) image is shown below. Figure 4 As shown, the microstructure of the thin film can significantly reduce the contact area between the flexible capacitive pressure sensing layer and the electrode, thereby significantly reducing the initial capacitance and improving sensitivity.

[0106] A flexible capacitive pressure sensing layer is prepared by naturally attaching the unstructured side of the microstructured ionogel membrane obtained in step 22) onto the ionogel electrospun membrane obtained in step 17).

[0107] 31) A silver layer is sputtered on the reverse side of the prepared vacuum filter membrane to prepare the first electrode.

[0108] 32) A silver layer is magnetron sputtered onto the silver-free surface of the electrode in 31), that is, a silver layer is magnetron sputtered onto the front side of the filtration film, so that there is a smooth silver layer on its surface. The filtration film is a natural shielding layer, so that the triboelectric nanogenerator and the flexible capacitive pressure sensor will not interfere with each other.

[0109] 33) Add 2g of PVDF-HFP to 20ml of acetone and stir at 70℃ for 1h to fully dissolve it, thus preparing a spin-coating solution.

[0110] 34) Spin-coating the solution at 500 rpm onto one side of the first electrode in 32) to prepare a double-sided electrode triboelectric nanogenerator. The spin-coating speed can be freely adjusted according to the solution concentration.

[0111] The bottom electrode is attached to one side of the capacitive flexible pressure sensing layer ion gel electrospun film, and the top electrode of the triboelectric nanogenerator is attached to the microstructured side of the microstructured ion gel film of the capacitive flexible pressure sensing layer.

[0112] Mix PDMS (polydimethylsiloxane) and curing agent at a ratio of 10:1 thoroughly for 30 minutes, then vacuum degas for 20 minutes, and cure at 80°C for 2 hours. Please refer to [link / reference]. Figure 1 By encapsulating PDMS on both sides of a triboelectric nanogenerator, the triboelectric layer is exposed and in contact with the object, thus fabricating a flexible multifunctional sensor.

[0113] The performance of a flexible multifunctional sensor disclosed in this embodiment is verified.

[0114] The selected sensor features a flexible capacitive sensing layer measuring 1cm x 2cm and a triboelectric nanogenerator measuring 1cm x 2cm. Silver paste is applied to the first, top, and bottom electrodes, which are then connected by copper wires to form the electrodes. A 1V voltage is applied to the electrodes at both ends of the flexible capacitive pressure sensor to form a circuit. The capacitance in the circuit is measured, and the experimental results are shown in Figure 3. Figure 7 As shown in the figure. The electrodes of the triboelectric nanogenerator are directly connected to the detection module to measure the triboelectricity. The experimental results are as follows. Figure 8 As shown.

[0115] Figures 3(a), 3(b), and 3(c) show time on the horizontal axis and capacitance on the vertical axis. These figures represent the stable response of the capacitance under different pressures, with each pressure level responded to three times. The pressure values ​​are marked above the three peak values. It can be observed that: 1. Under the same pressure, the device exhibits a stable response capacitance, with a high waveform repetition rate; the capacitance fluctuation is small when the same pressure is applied. 2. Under different pressures, the capacitance increases with increasing pressure, indicating that the capacitance increases with increasing pressure and the capacitance change is stable. Figure 7The sensitivity curves of the flexible capacitive pressure sensing layer to pressure are shown in Figures (a), 3(b), and 3(c). Figure 7 As can be seen, the sensor disclosed in this embodiment has an extremely small detection limit (0.6 Pa), a wide detection range, and high sensitivity. Figure 8 This study demonstrates the voltage variation of a triboelectric nanogenerator under different pressures. Due to the waveform characteristics of the triboelectric nanogenerator, the electropositivity and electronegativity of objects can be distinguished. If an electropositivity polymer material is used as the friction layer, the waveform when it contacts an electropositivity object is opposite to that when it contacts an electronegative object, thus indicating the object's properties, i.e., distinguishing its positive and negative charge. The voltage amplitude and polarity generated by different materials are shown below. Figure 13 As shown.

[0116] It should be noted that traditional flexible sensors are mostly standalone pressure sensors or triboelectric nanogenerators, which can only distinguish the magnitude of pressure and have a small pressure detection range. They cannot simultaneously detect the wearer's movements and the nature of the object being touched.

[0117] The flexible multifunctional sensor prepared in this embodiment employs a structure combining a flexible capacitive pressure sensing layer and a triboelectric nanogenerator, enabling simultaneous detection of the wearer's movements and the properties of objects touched. The flexible capacitive pressure sensing layer is composed of a microstructured ionogel membrane and an ionogel electrospun membrane. The microstructures on the ionogel membrane significantly reduce the contact area between the flexible capacitive pressure sensing layer and the top electrode, improving sensitivity. When subjected to small pressure, the contact area between the microstructure and the top electrode increases, increasing the device's specific capacitance and thus triggering a response. When the contact area reaches saturation, increasing the pressure causes the electrospun membrane to expel air, making the structure more compact and further increasing the specific capacitance, thereby expanding the device's sensing range. Simultaneously, combined with the triboelectric nanogenerator, it can detect not only the wearer's movements but also the properties of objects touched. The data is transmitted to a computer for intelligent judgment, and then the signal is transmitted to a virtual character, achieving a better human-computer interaction effect.

[0118] The flexible multifunctional sensor disclosed in this embodiment can not only perform human-computer interaction with hand movements, but also expand to include whole-body sensors and monitor fist and foot movements in contact with the outside world, as well as robot sensing, etc.

[0119] Example 2

[0120] In this embodiment, a method for fabricating a flexible multifunctional sensor disclosed in Embodiment 1 is disclosed, comprising:

[0121] Ion gel electrospun membranes, microstructured ion gel membranes, and double-sided electrodes were prepared respectively.

[0122] Microstructured ionogel membranes and ionogel electrospun membranes are bonded together to form a flexible capacitive pressure sensing layer.

[0123] A triboelectric nanogenerator is formed by spin-coating a triboelectric layer onto one of the electrodes of a double-sided electrode.

[0124] Triboelectric nanogenerators are attached to microstructured ionogel membranes.

[0125] The bottom electrode is attached to the ion gel electrospun membrane.

[0126] Example 3

[0127] In this embodiment, a human-computer interaction system based on a flexible multifunctional sensor is disclosed, such as... Figure 12 As shown, it includes:

[0128] Example 1 discloses a flexible multifunctional sensor for attaching to the joints and fingertips of a wearer's hand;

[0129] The control system is used to determine the wearer's movements and the nature of the objects grasped based on signals detected by flexible multi-functional sensors at the joints and fingertips, and to control the virtual character to imitate the wearer's movements.

[0130] Control the virtual character to perform grasping or touching actions.

[0131] When wearing a flexible multi-functional sensor, the friction layer of the sensor needs to be in contact with the skin of the finger or with the glove on the finger. A schematic diagram of wearing a flexible multi-functional sensor on the fingertip is shown below. Figure 9 As shown in the diagram, a schematic of a flexible multifunctional sensor on a joint is as follows: Figure 10 As shown.

[0132] The control system first models the virtual character. After the model is established, an intelligent human-computer interaction example is conducted. The virtual character judges the wearer's movements based on the detection signals of the flexible multi-functional sensors attached to each joint and fingertip, and then imitates the wearer's movements.

[0133] Specifically, the control system determines that the wearer and the virtual character are not moving when neither the flexible multi-functional sensor at the joint nor the flexible multi-functional sensor at the fingertip detects a signal. Figure 11 As shown.

[0134] The control system determines the wearer's action as a grasping motion when the flexible multi-functional sensor at the joint detects a signal. If the flexible multi-functional sensor at the fingertip does not detect a signal, it indicates that the wearer made a grasping motion but did not actually touch an object (e.g., grasping at air). If the flexible multi-functional sensor at the fingertip detects a signal, it uses the signal from the triboelectric nanogenerator within the sensor to determine the nature of the grasped object. Different gripping forces result in different pressure signals detected by the sensor, causing the virtual character to grasp with varying degrees of force. When the signal from the triboelectric nanogenerator in the fingertip sensor indicates the contact with an incorrect object, the virtual character performs different degrees of injury based on the gripping force. The control system records the signals detected by the flexible multi-functional sensor at the fingertip when grasping an incorrect object. When the flexible multi-functional sensor at the fingertip does not detect a signal, the virtual character will follow the wearer's hand movements until the sensor at the fingertip sends a detection signal and data.

[0135] The control system determines that the wearer's action is a touch action when the flexible multi-functional sensor at the joint does not detect a signal, but the flexible multi-functional sensor at the fingertip detects a signal. It then controls the virtual character to perform the touch action and determines the nature of the contacted object based on the signal from the triboelectric nanogenerator in the flexible multi-functional sensor at the fingertip. If the wearer is determined to have touched the correct object, the virtual character will perform different actions according to the pressure data, such as touching the object with its finger or picking up the object. If the wearer is determined to have touched the wrong object, the virtual character will perform an injury action, such as a finger stimulation action.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A flexible multifunctional sensor, characterized in that, It includes a triboelectric nanogenerator, a flexible capacitive pressure sensing layer, and a bottom electrode arranged sequentially from the top to the bottom. The triboelectric nanogenerator includes a triboelectric layer and a double-sided electrode. The triboelectric layer is located on one side of the double-sided electrode, and the other side of the double-sided electrode is attached to a microstructured ionogel membrane. The double-sided electrode includes a first electrode, an isolation layer, and a top electrode. The first electrode and the top electrode are respectively disposed on two sides of the isolation layer. The triboelectric layer is disposed on the first electrode, and the top electrode is attached to the microstructured ionogel membrane. Triboelectric nanogenerators are used to distinguish the electropositivity and electronegativity of objects by voltage waveform characteristics: when an electropositive polymer material is used as a friction layer, the voltage waveform generated when it touches an electropositive object is opposite to that when it touches an electronegative object, thereby distinguishing the electropositivity and electronegativity of the object and realizing the detection of the properties of the contacting object. The flexible capacitive pressure sensing layer comprises a microstructured ionogel membrane and an ionogel electrospun membrane attached together. Microstructured ionogel membranes are used to fabricate multiple microstructures on one side of the bi-sided electrode; The bottom electrode is attached to the ion gel electrospun membrane.

2. The flexible multifunctional sensor as described in claim 1, characterized in that, A substrate is also provided at the bottom of the bottom electrode.

3. The flexible multifunctional sensor as described in claim 1, characterized in that, The microstructured ionogel membrane was prepared by means of a mixed cellulose containing cellulose acetate and cellulose nitrate, and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

4. A flexible multifunctional sensor as described in claim 1, characterized in that, The ion gel electrospun membrane consists of multiple composite nanofibers, and each composite nanofiber contains MXene.

5. A flexible multifunctional sensor as described in claim 1, characterized in that, The two ends of the triboelectric nanogenerator are encapsulated by an encapsulation film, while the triboelectric layer is partially exposed.

6. The method for fabricating a flexible multifunctional sensor as described in any one of claims 1-5, applied to the flexible multifunctional sensor as described in any one of claims 1-5, characterized in that, include: Ion gel electrospun membranes, microstructured ion gel membranes, and double-sided electrodes were prepared respectively. Microstructured ionogel membranes and ionogel electrospun membranes are bonded together to form a flexible capacitive pressure sensing layer. A triboelectric nanogenerator is formed by spin-coating a triboelectric layer onto one of the electrodes of a double-sided electrode. Triboelectric nanogenerators are attached to microstructured ionogel membranes. The bottom electrode is attached to the ion gel electrospun membrane.

7. A human-computer interaction system based on a flexible multifunctional sensor, characterized in that, include: The flexible multifunctional sensor as described in any one of claims 1-5 is used to be attached to the joints and fingertips of the wearer's hand; The control system is used to determine the wearer's movements and the nature of the objects grasped based on signals detected by flexible multi-functional sensors at the joints and fingertips, and to control the virtual character to imitate the wearer's movements.

8. The human-computer interaction system based on a flexible multifunctional sensor as described in claim 7, characterized in that, The control system is used to determine that the wearer is not moving when neither the flexible multi-functional sensor at the joint nor the flexible multi-functional sensor at the fingertip detects a signal. When the flexible multi-functional sensor at the joint detects a signal, it determines that the wearer's action is a grasping action; When the flexible multi-functional sensor at the joint does not detect a signal, but the flexible multi-functional sensor at the fingertip detects a signal, the wearer's action is determined to be a touch action. The nature of the object being contacted is determined by the triboelectric nanogenerator signal from the flexible multifunctional sensor at the fingertip.

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