Intelligent cushion for monitoring sitting posture in real time in field of medical care and preparation method of intelligent cushion

Abstract

The invention discloses a real-time sitting posture monitoring intelligent cushion for the field of medical care and a preparation method of the real-time sitting posture monitoring intelligent cushion, and belongs to the technical field of conductive polymer composite materials and flexible electronics. The preparation method of the intelligent cushion for real-time sitting posture monitoring comprises the following steps: preparing a polymer spinning solution, carrying out electrostatic spinning on a receiver wrapped with a template to obtain a polymer fiber film with an ordered micro-bulge array structure, and then immersing the polymer fiber film into a conductive material solution for dip-coating treatment to obtain the intelligent cushion for real-time sitting posture monitoring. And assembling with an interdigital electrode to obtain the flexible pressure sensor. And fixing the pressure sensor on a flexible substrate to obtain the intelligent cushion. The flexible pressure sensor has excellent sensitivity, pressure response range and durability. After a plurality of flexible pressure sensors are integrated into the intelligent cushion system, not only can pressure distribution be visualized, but also a specific sitting posture can be accurately identified.

Description

Technical Field

[0001] This invention relates to the fields of conductive polymer composite materials and flexible electronics, and in particular to a smart seat cushion for real-time posture monitoring in the field of healthcare and its preparation method. Background Technology

[0002] Prolonged poor posture is a significant contributing factor to musculoskeletal disorders such as chronic lower back pain, cervical spondylosis, and herniated discs, as well as related complications (such as pressure sores). In clinical rehabilitation and geriatric care, continuous monitoring of patient posture is crucial for evaluating treatment effectiveness and optimizing rehabilitation programs. Currently, pressure-sensor-based monitoring platforms are the mainstream technology for quantifying posture; however, traditional commercial pressure-sensor pads still have inherent limitations, such as long measurement times, fixed usage scenarios, and difficulty in achieving continuous daily monitoring, requiring further improvement.

[0003] In recent years, wearable electronic devices integrating flexible pressure sensors into seats have gradually become a promising solution. To improve the overall performance of flexible pressure sensors, it is usually necessary to construct microstructures on the surface of their sensitive layer to control their contact area with the electrodes. Existing microarray manufacturing technologies, such as photolithography, nanoimprinting, and 3D printing, while effective, generally suffer from problems such as complex processes, high costs, or difficulty in large-scale production. In contrast, electrospinning technology, with its advantages of low cost, high efficiency, and suitability for large-scale preparation, shows great promise in the fabrication of micro and nanofiber films. Introducing microstructures through template-assisted electrospinning can effectively optimize the performance parameters of sensors. However, developing a fully integrated smart cushion system that combines high sensitivity, wide detection range, excellent stability, and the ability to accurately acquire pressure data, visualize it in real time, and intelligently recognize sitting posture remains a major challenge for current research. Summary of the Invention

[0004] The purpose of this invention is to provide a smart cushion for real-time posture monitoring in the healthcare field and a method for its fabrication, thereby addressing the aforementioned problems in the background art. The flexible pressure sensor of this invention possesses excellent sensitivity, pressure response range, and durability. Integrating multiple flexible pressure sensors into the smart cushion system of this invention not only allows for visualization of pressure distribution but also accurate identification of specific sitting postures.

[0005] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is: a method for preparing a smart seat cushion for real-time monitoring of sitting posture, comprising the following steps: Prepare a polymer spinning solution and perform electrospinning on a receiver coated with a template to obtain a polymer fiber film with an ordered micro-protrusion array structure. The polymer fiber film is subjected to oxygen plasma treatment, and then immersed in a conductive material solution for dip coating to obtain a conductive polymer fiber film sensitive layer. The conductive polymer fiber film sensitive layer is assembled with interdigitated electrodes to obtain a flexible pressure sensor; The pressure sensor is fixed on a flexible substrate to obtain the smart cushion.

[0006] Preferably, the template is a copper mesh with a mesh count of 16-200, and more preferably a copper mesh with a mesh count of 50.

[0007] Preferably, the polymer material in the polymer spinning solution is one or more of polylactic acid, polycaprolactone, polylactic acid-glycolic acid copolymer, polyurethane, polystyrene, polyacrylonitrile, polymethyl methacrylate and polyamide, and the solvent is one or more of DMF (N,N-dimethylformamide), THF (tetrahydrofuran), chloroform and hexafluoroisopropanol.

[0008] Preferably, the polymer material in the polymer spinning solution is one or more of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, sodium alginate, gelatin, and cellulose and their derivatives, and the solvent is water.

[0009] Preferably, the electrospinning parameters are: spinning voltage of 5-30 kV, feed rate of 1.0 mL / h, and receiving distance of 15 cm.

[0010] Preferably, the oxygen plasma treatment time is 1-5 min.

[0011] Preferably, the conductive material in the conductive material solution is one or more of MXene nanosheets, carbon nanotubes, carbon black, and graphene; the concentration of the conductive material in the conductive material solution is 50 g / L.

[0012] Preferably, the dip coating process is performed 1-20 times, and drying is carried out after each dip coating.

[0013] Preferably, the assembly includes the following steps: face-to-face bonding with the ordered micro-protrusion array structure of the conductive polymer fiber film sensitive layer facing the electrode.

[0014] Preferably, the method of fixing the pressure sensor on the flexible substrate is as follows: the pressure sensor is fixed on the flexible substrate in the form of an M×N pixel array to form a seat cushion sensing array.

[0015] The second technical solution of the present invention provides an intelligent seat cushion for real-time monitoring of sitting posture, obtained according to the above preparation method.

[0016] The third technical solution of the present invention provides an application of the above-mentioned smart seat cushion for real-time monitoring of sitting posture in the field of sitting posture monitoring.

[0017] This invention prepares a fiber film sensitive layer with an ordered micro-protrusion array structure by using a template-assisted electrospinning method. Then, a conductive network is constructed on the surface and inside of the sensitive layer by an impregnation method. The micro-protrusion side is then assembled face-to-face with interdigitated electrodes to obtain a flexible pressure sensor. Finally, the assembled flexible pressure sensor is fixed according to the position of an M×N pixel matrix to obtain the intelligent cushion system of this invention.

[0018] The beneficial technical effects of the present invention are as follows: This invention utilizes a microstructure of surface micro-protrusions to create a flexible pressure sensor with high sensitivity, a wide and excellent pressure response range, and durability. This intelligent cushion system can collect real-time data on hip pressure distribution and can be widely applied to posture correction for people who sit for long periods, early prevention of intervertebral disc diseases and pressure ulcers, and efficacy evaluation for rehabilitation patients.

[0019] The micro-protrusion array structure in this invention is formed in one step using a template-assisted electrospinning method, avoiding complex and expensive microfabrication techniques and making it suitable for mass production. The resulting flexible pressure sensor exhibits a significant change in contact area under pressure, achieving high sensitivity (up to 293.7 kPa). -1 It features a wide detection range (3.8-300 kPa), fast response / recovery (40ms), and excellent cycle durability (>2000 cycles). By integrating multiple flexible pressure sensors into the intelligent cushion system of this invention, not only can pressure distribution be visualized, but specific sitting postures can also be accurately identified, achieving a leap from "perception" to "cognition." The intelligent cushion system of this invention has the advantages of being lightweight, flexible, portable, and having stable mechanical properties. It can be applied to various scenarios such as offices, homes, and rehabilitation centers, and can provide effective health monitoring and management solutions for people who sit for long periods, patients with spinal diseases, and patients at risk of pressure ulcers, demonstrating significant application value. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating the fabrication process of the flexible pressure sensor according to Embodiment 1 of the present invention; Figure 2This is a scanning electron microscope image of the surface of the micro-protrusion array nanofiber thin film sensitive layer of Embodiment 1 of the present invention; Figure 3 These are scanning electron microscope images of the sensitive layers of micro-protrusion array nanofiber thin films prepared with the assistance of copper mesh templates of different mesh counts in Example 1 and Comparative Example 1 of the present invention. Figure 4 This is a sensitivity comparison diagram of the flexible pressure sensors prepared with the assistance of copper mesh templates of different mesh counts in Example 1 and Comparative Example 1 of the present invention. Figure 5 This is a pressure sensitivity test of the flexible pressure sensor in Embodiment 1 of the present invention; wherein, a is the sensitivity curve, b is the current-voltage (IV) characteristic curve under pressure of 8.3-300 kPa, c is the current change rate under pressure of 8.3-300 kPa, d is the response recovery time of the flexible pressure sensor, and e is the current change curve of 2000 loading / unloading tests under pressure of 58.3 kPa. Figure 6 This is a schematic diagram illustrating the application of the intelligent cushion system composed of a 4×9 flexible sensor array in the medical and health field in Embodiment 1 of the present invention. Figure 7 This is a diagram illustrating the real-time posture monitoring effect of the intelligent seat cushion system according to Embodiment 1 of the present invention. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0023] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. It should be noted that any aspects of this invention not described in detail are conventional practices in the art and are not the focus of this invention.

[0025] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0026] In the following embodiments and comparative examples of the present invention, the LiF used had a molecular weight of 25.94 and was purchased from Beijing Innocare Technology Co., Ltd.; HCl was purchased from Kaifeng Fangjing Chemical Reagent Co., Ltd.; the TPU (thermoplastic polyurethane elastomer) was model 1185A and was purchased from BASF GmbH, Germany; the copper mesh (50 mesh) was purchased from Changzhou Qiaozhen Screening Co., Ltd.; the interdigitated electrodes were purchased from Shenzhen Xipu'ao Electronic Technology Co., Ltd.; and the flexible substrate was a commercial nonwoven fabric.

[0027] Unless otherwise specified, "room temperature" in this invention refers to 10-30°C.

[0028] All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.

[0029] Example 1 A method for fabricating a flexible pressure sensor with a dual microstructure and a smart cushion system assembled therefrom, comprising the following steps: 1) MXene nanosheets were prepared by selectively etching the Al phase of Ti3AlC2 (MAX phase): 1.6 g of lithium fluoride (LiF) powder was dispersed in a polytetrafluoroethylene beaker containing 20 mL of HCl (9 mol / L) solution, and then 1.0 g of Ti3AlC2 was added. The mixture was stirred at 45 °C for 24 h. The resulting solution was then washed with deionized water until the pH of the supernatant was 6-7 and the color was dark green. The supernatant was then centrifuged at high speed to obtain the precipitate. Finally, the precipitate was redispersed in deionized water and sonicated in an ice-water bath for 1 h to obtain a homogeneous MXene solution composed of single-layer and / or multi-layer sheets. 2) Weigh 5 g of TPU particles and dissolve them in 25 mL of DMF / THF (volume ratio 1:1) mixed solvent. Stir magnetically at room temperature until completely dissolved to form a homogeneous and transparent spinning solution. Inject the spinning solution into a syringe and spin using an electrospinning device. The receiving device is a roller wrapped with a 50-mesh copper mesh (1 mm thick). Set the spinning voltage to 20 kV, the feed rate to 1.0 mL / h, and the receiving distance to 15 cm. After spinning, carefully peel the nanofiber film off the copper mesh and place it in a fume hood to thoroughly remove residual solvent, obtaining a TPU nanofiber film with an ordered micro-protrusion array. Subsequently, place the TPU nanofiber film in a Plasma cleaner for 2 min of oxygen plasma treatment to make it more hydrophilic. Finally, immerse the treated film in MXene solution, remove it after wetting, and dry it at room temperature. Repeat this immersion-drying process 5 times to finally obtain a conductive micro-protrusion array nanofiber film sensitive layer. 3) Cut the prepared micro-protrusion array nanofiber film sensitive layer into a size of 1×1 cm, and attach it face to face with the commercially available interdigitated electrode with the sensitive layer micro-protrusion facing the electrode. Press it lightly to make good contact, thus forming an independent flexible pressure sensor. 4) Take a commercial nonwoven fabric with a size of 25 cm × 30 cm as a flexible substrate and mark 36 fixed points in 4 rows and 9 columns on it; attach the 36 flexible pressure sensors from step 3) to each of the fixed points, and connect the wires to the electrodes on both sides of the interdigital electrode of each sensor to output electrical signals, and finally assemble the intelligent cushion system.

[0030] 5) Connect the assembled smart cushion system to the data acquisition card via wires. Invite a volunteer weighing approximately 65 kg to sit on the cushion and change their sitting posture in sequence (sitting upright, leaning forward, crossing the left leg, crossing the right leg, etc.). Extract features from the collected current signals, construct a dataset, and perform two-dimensional signal processing to make it directly visual. This allows for intuitive, effective, and accurate identification of different sitting postures. The test results are as follows: Figure 6 As shown.

[0031] Figure 1 This is a flowchart illustrating the fabrication process of the flexible pressure sensor according to Embodiment 1 of the present invention.

[0032] Examples 2-5 (different types of conductive materials) The only difference from Example 1 is that the MXene solution in step 2) is replaced with carbon black aqueous dispersion, carbon nanotube aqueous dispersion, silver nanowire aqueous dispersion and graphene aqueous dispersion of the same mass concentration.

[0033] Comparative Example 1 The only difference from Example 1 is that the copper mesh in step 2) has a different mesh count (0 mesh, 16 mesh, 100 mesh, 200 mesh), resulting in different micro-protrusion structures on the surface of the prepared fiber membrane, which affects the sensitivity of the flexible sensor.

[0034] Comparative Example 2 The only difference from Example 1 is that the fixed sites in step 4) are modified to 10 sites in 2 rows and 5 columns.

[0035] Comparative Example 3 The only difference from Example 1 is that the fixed sites in step 4) are modified to 21 sites in 3 rows and 7 columns.

[0036] Effect verification 1. Microscopic morphological observation Take the micro-protrusion array nanofiber thin film sensitive layer from step 2 of Example 1, observe it under an optical microscope, and then perform gold sputtering on the film and observe it under a scanning electron microscope (model JSM-7610FPlus).

[0037] Figure 2 This is a surface scanning electron microscope image of the sensitive layer of the micro-protrusion array nanofiber thin film in Embodiment 1 of the present invention.

[0038] Figure 3 These are surface scanning electron microscope images of the sensitive layers of nanofiber thin films with different microprotrusion array structures in Example 1 and Comparative Example 1 of the present invention.

[0039] Figure 3 In the middle, the five small images from the left (1, 2, 3, 4, and 5) represent the relevant data of the samples with copper mesh counts of 0, 16, 50, 100, and 200 in Example 1 and Comparative Example 1, respectively.

[0040] like Figure 2 As shown, MXene can be clearly seen tightly adhering to the fiber surface, forming a bark-like microstructure; from Figure 3 Different micro-protrusion array structures can be observed on the surface of the sensitive layer prepared with the assistance of copper mesh of different mesh counts. The protrusion array obtained by the 50-mesh copper mesh template is clearer.

[0041] 2. Sensor performance testing The interdigitated electrodes in the flexible pressure sensor of Example 1 are connected to an electrochemical workstation (RST5200) using wires. The electrochemical workstation can apply a voltage of 0.3 volts to the sample and output the real-time current change of the sample.

[0042] By applying different pressures to the sample using a universal testing machine, and recording the real-time current value using an electrochemical workstation, the pressure sensitivity performance of the flexible pressure sensor can be tested.

[0043] Figure 4 This is a sensitivity comparison diagram of the flexible pressure sensors prepared with the aid of copper mesh templates of different mesh counts in Embodiment 1 and Comparative Example 1 of the present invention. The sensitivity is highest when a 50-mesh copper mesh is used as the template; therefore, the surface micro-protrusion structure has an enhancing effect on sensitivity.

[0044] Figure 5 The pressure sensitivity test of the flexible pressure sensor in Embodiment 1 of the present invention is shown in the figure. Here, a is the sensitivity curve; b is the current-voltage (IV) characteristic curve under pressure of 8.3-300 kPa; c is the current change rate under pressure of 8.3-300 kPa; d is the response time of the flexible pressure sensor, both of which are 40 ms; and e is the current change rate under 2000 loading / unloading tests at pressure of 58.3 kPa. It can be seen that the pressure sensor exhibits a stable signal during long-term cyclic testing.

[0045] Figure 6 This is a schematic diagram illustrating the application of the intelligent cushion system composed of a 4×9 flexible sensor array in the medical and health field in Embodiment 1 of the present invention.

[0046] Figure 7 The invention demonstrates the application of the intelligent cushion system in terms of usage scenarios, structural composition, and signal visualization output. Two-dimensional mapping signals illustrate the force distribution in different sitting postures (including sitting upright, leaning forward, crossing the right leg, crossing the left leg, and standing); these two-dimensional mapping signals allow for intuitive, effective, and accurate identification of different sitting postures.

[0047] In summary, this invention discloses a smart seat cushion for real-time posture monitoring in the healthcare field and its preparation method. It can be applied in long-term posture monitoring environments where high comfort and durability are required. Furthermore, the preparation method is simple, rapid, low-cost, and produces a product with stable mechanical properties. Specifically, it solves the problems of low sensitivity, narrow detection range, and inability to perform long-term dynamic monitoring in traditional monitoring equipment, achieving integrated "sensing-visualization-recognition" functions. It has promising applications and development prospects in fields such as smart healthcare, telemedicine, smart office furniture, and clinical biomechanical analysis.

[0048] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a smart seat cushion for real-time monitoring of sitting posture, characterized in that, Includes the following steps: Prepare a polymer spinning solution and perform electrospinning on a receiver coated with a template to obtain a polymer fiber film with an ordered micro-protrusion array structure. The polymer fiber film is subjected to oxygen plasma treatment, and then immersed in a conductive material solution for dip coating to obtain a conductive polymer fiber film sensitive layer. The conductive polymer fiber film sensitive layer is assembled with interdigitated electrodes to obtain a flexible pressure sensor; The pressure sensor is fixed on a flexible substrate to obtain the smart cushion.

2. The preparation method according to claim 1, characterized in that, The template is a copper mesh with a mesh count of 16-200.

3. The preparation method according to claim 1, characterized in that, The electrospinning parameters are: spinning voltage of 5-30 kV, feed rate of 1.0 mL / h, and receiving distance of 15 cm.

4. The preparation method according to claim 1, characterized in that, The oxygen plasma treatment time is 1-5 minutes.

5. The preparation method according to claim 1, characterized in that, The conductive material in the conductive material solution is one or more of MXene nanosheets, carbon nanotubes, carbon black, and graphene; the concentration of the conductive material in the conductive material solution is 50 g / L.

6. The preparation method according to claim 1, characterized in that, The assembly includes the following steps: face-to-face bonding with the ordered micro-protrusion array structure of the conductive polymer fiber film sensitive layer facing the electrode.

7. The preparation method according to claim 1, characterized in that, The method of fixing the pressure sensor on the flexible substrate is as follows: the pressure sensor is fixed on the flexible substrate in the form of an M×N pixel array, which together form a cushion sensing array.

8. A smart seat cushion for real-time monitoring of sitting posture, obtained by the preparation method according to any one of claims 1-7.

9. The application of the smart seat cushion for real-time monitoring of sitting posture as described in claim 8 in the field of sitting posture monitoring.

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