A method for manufacturing a skin sensor, the skin sensor and applications thereof

Abstract

The application discloses a preparation method of a skin sensor, the skin sensor and application thereof, and belongs to the field of sensors. The preparation method comprises the following steps: (1) taking an LTM film with a thickness of 50-1000 nm, wetting the LTM film by using an alcohol organic solvent, and discharging air in the gap inside the LTM film; then, soaking the LTM film in deionized water, so that the water contact angle of the LTM film reaches 30-90 DEG to realize water solvation, and the LTM film is taken out immediately for the next step; (2) setting a water-soluble mask layer on the surface of the water-solubated LTM film, and the water-soluble mask layer is provided with a hollow shape; placing the LTM film provided with the water-soluble mask layer on a metal block, and then preparing a conductive electrode; placing the LTM film after the preparation of the conductive electrode in water, and separating the water-soluble mask layer, and the skin sensor is obtained. The skin sensor can provide strong support for wearable medical treatment and the realization of real-time and personalized health monitoring, and is expected to promote the development of wearable medical treatment and real-time and personalized health monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sensors, in particular to a preparation method of a skin sensor, the skin sensor and application thereof. BACKGROUND

[0002] Since the 1980s, some foreign research institutions have begun to study flexible sensors and apply them in the field of medicine. At present, wearable devices represented by smart watches have been used for long-term monitoring of physiological parameters of the human body (such as blood pressure, heart rate (HR) pulse, body temperature, blood sugar level, exercise mode, etc.) to monitor and improve human health, and have become more and more popular. The sensors of the existing wearable devices are usually composed of air-impermeable flexible rubber, such as PDMS, Ecoflex, PVDF, etc.; during long-term use, sweat between the sensor and the skin will greatly affect the accuracy of the results and cause skin discomfort or allergy, etc.

[0003] Therefore, a large amount of research has been conducted. For example, Chinese Patent Application CN113237581A discloses a skin hardness sensor and a manufacturing method thereof, which includes a spiral electrode and a disc electrode preparation step, and a pressure-sensitive capacitor material preparation step. The spiral electrode and disc electrode preparation step is as follows: mixing nano-silver wire and carbon nanotubes in a mass ratio of 1:1, then dispersing them in an alcohol solution; patterning a polyimide film attached to a glass sheet; spraying nano-silver wire / carbon nanotube conductive particles on the glass sheet; drying at a first temperature for a first duration; after removing the excess polyimide film, pouring polydimethylsiloxane onto the electrode and penetrating it into the conductive particle network through vacuum action; after curing the polydimethylsiloxane, the polydimethylsiloxane is removed from the glass surface, and the nano-silver wire / carbon nanotube conductive particles are embedded in the surface of the polydimethylsiloxane, forming the spiral electrode and the disc electrode. The skin hardness sensor can be applied to quantitative analysis of the skin hardness of patients with scleroderma, thereby judging the prognosis and treatment effect of the patients, and can also be applied to skin state evaluation of healthy people.

[0004] Chinese Patent Application CN113049150A discloses a flexible pressure sensor, a preparation method thereof and a robot skin and wearable device. The flexible pressure sensor includes a flexible base layer, and the flexible base layer includes a first flexible base layer and a second flexible base layer. The first flexible base layer and the second flexible base layer are selected from a flexible insulating material, and the flexible insulating material is selected from at least one of silicone rubber, sulfur rubber, polyethylene, polyamide and polytetrafluoroethylene.

[0005] Chinese patent application CN110693469A discloses an electronic skin with a hierarchical pressure peak structure and a preparation method thereof, which comprises the following steps: preparing a flexible substrate with a pressure-sensitive sensing layer sputtered on the surface; preparing an electrode packaging layer with an insulating mesh layer; preparing a retainer and packaging. In this structure, the flexible substrate, the pressure-sensitive sensing layer, the retainer and the electrode packaging layer can all be flexible materials, which can be attached to different positions such as the lower end of the nose, the radial artery of the wrist, the fingers and the soles of the feet, and thus can be well applied to the field of human physiological signal detection and robots.

[0006] Chinese patent application CN110383021A discloses a blood pressure measurement system using a resistive force sensor array, which includes a sensor element composed of a conductive film as a substrate. The sensor element can be implemented in a cross-finger type or an opposite configuration. The sensor array further includes a mechanical interface on top of the sensor element for transmitting or focusing the applied pressure to the conductive film.

[0007] Chinese patent application CN107345840A discloses a flexible force-sensitive sensor based on silver-loaded nanofiber and a preparation method thereof. The sensor includes a flexible force-sensitive resistance film, which is connected in series with a power supply and an ammeter. The flexible force-sensitive resistance film includes a silver-loaded nanofiber film, which is composed of alginate / silver nanoparticle composite nanofiber. The alginate / silver nanoparticle composite nanofiber is obtained by electrospinning sodium alginate nanofiber, ion exchange to obtain silver alginate nanofiber, and reduction of silver ions. The sensitive resistance of the sensor has good flexibility, can be directly adhered to the skin without damaging the skin, has good temperature resistance and sensitivity, and can realize the monitoring of physiological activities such as pulse, respiratory rate and heartbeat. At the same time, it also has antibacterial effect and is safer when directly contacting with the skin.

[0008] Chinese patent application CN114739561A discloses a silk protein-based anti-sweat flexible pressure sensor and a method and application thereof, which comprises two electrode layers and an ion dielectric layer sandwiched in the middle, wherein the electrode layer is a silk protein film with a micro-protrusion structure and a gold pattern, and the ion dielectric layer is a silk protein / ion liquid fiber felt; and the high air permeability of the silk protein material itself and the fiber structure makes the sensor have good air permeability and anti-sweat ability, which can accurately measure blood pressure under the condition of long-term wearing or skin sweating.

[0009] The inventors have found in practice that in some cases, the existing epidermal sensors for skin cannot meet the needs of practical applications. For example, for postoperative patients, a non-invasive flexible sensor is usually attached to the surface of the patient's skin to continuously monitor the patient's vital sign parameters; due to the poor air permeability and biocompatibility of the existing flexible sensor, when the flexible sensor is worn for a period of time, the sweat on the skin surface cannot be effectively discharged, and the sweat accumulated under the flexible sensor can easily cause skin discomfort or allergy, such as red rash, and in severe cases, can develop into pressure sores, and also affect the accuracy of the detection results. Because the skin after surgery is sensitive, methods that provide adhesion through chemical components such as adhesive tape and glue, or physical fixation methods based on pressure such as bandages, can cause varying degrees of discomfort or inflammation when used for a long time. Thinner film materials can provide better self-adhesion, but in material science, there is a certain contradiction between thinness and porosity. Especially for film materials with a thickness of less than 1 micrometer, in order to maintain thermodynamic stability, materials that can provide pore sizes of more than 100 nanometers and high porosity are very rare. Self-supporting film materials on the market with a thickness of less than 1 micrometer are almost non-porous and dense. In addition, when the thickness of the film material is less than 1 micrometer, it is difficult to prepare the corresponding sensor. Therefore, there is an urgent need for nanoscale epidermal sensors, especially an epidermal sensor for skin surface detection that has good air and water permeability and can be self-adhesive, to solve the above problems. SUMMARY

[0010] One of the purposes of the present application is to provide a preparation method of an epidermal sensor, which uses an ultra-high molecular weight polyethylene ultra-thin film as a base material to prepare a sensor with a nanoscale thickness.

[0011] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0012] A preparation method of an epidermal sensor, comprising the following steps:

[0013] (1) Take an ultra-high molecular weight polyethylene ultra-thin film with a thickness of 50-1000 nm, wet the ultra-high molecular weight polyethylene ultra-thin film with an alcohol organic solvent to expel the air inside the voids of the ultra-high molecular weight polyethylene ultra-thin film; then soak it with deionized water to make the water contact angle of the ultra-high molecular weight polyethylene ultra-thin film reach 30-90° to achieve water solvation, and immediately take it out for the next step;

[0014] (2) setting a water-soluble mask layer on the surface of the water-solvent UHMWPE ultra-thin film after water-solvent, the water-soluble mask layer is provided with a hollow shape; then placing the UHMWPE ultra-thin film provided with the water-soluble mask layer on a metal block, and then preparing a conductive electrode; in the process of preparing the conductive electrode, the metal block provides external support for the UHMWPE ultra-thin film and leads out heat; finally, placing the UHMWPE ultra-thin film after the preparation of the conductive electrode in water, and after the water-soluble mask layer is separated from the UHMWPE ultra-thin film, the UHMWPE ultra-thin film provided with the conductive electrode on the surface is obtained, that is, a skin sensor.

[0015] Further comprising the following steps:

[0016] (3) after obtaining the UHMWPE ultra-thin film provided with the conductive electrode on the surface, setting an electrochemically active material on the surface to obtain a skin sensor with the UHMWPE ultra-thin film, the conductive electrode and the electrochemically active material integrated.

[0017] The hollow shape is determined based on the designed electrode circuit, different electrode circuits correspond to different shapes, and is related to the actual designer.

[0018] Further, the electrochemically active material is fixedly arranged on the metal circuit layer in a deposition or coating manner.

[0019] Further, the coating manner is manual coating or 3D printing coating.

[0020] The alcohol organic solvent is one or more of ethanol and isopropyl alcohol.

[0021] In the step (1), the porosity of the UHMWPE ultra-thin film is 30-70%, and the pore diameter is 10-200 nm.

[0022] In the step (2), the conductive electrode is prepared by magnetron sputtering.

[0023] The sputtering target material used in the magnetron sputtering is one or more of chromium, gold and platinum.

[0024] The preparation method of the UHMWPE ultra-thin film is as follows: uniformly mixing and stirring UHMWPE resin and expansion solvent at 100-150℃ to prepare a first suspension; extruding the first suspension into a gel thin film, and then stretching the prepared gel thin film; aging the stretched ultra-gel thin film at 120-140℃ for 30 minutes; after the aging treatment is completed, solvent extraction is performed to remove the expansion solvent, and then drying at 60℃ for 1-10h to obtain the UHMWPE ultra-thin film (abbreviated as: LTM).

[0025] The swelling solvent is one or more of vaseline, mineral oil.

[0026] The solvent used in the extraction is one or more of hot hexachloroethane, acetone, decaline.

[0027] The first suspension is extruded into a gel film using a twin-screw extruder, and the gel film is stretched twice on a universal tensile testing system.

[0028] The aging treatment condition is 125℃ for 30 minutes.

[0029] The skin sensor is prepared using the aforementioned method.

[0030] The skin sensor prepared using the aforementioned method uses an ultrahigh molecular weight polyethylene ultrathin film with a thickness of 50-1000nm as the base material, and the ultrahigh molecular weight polyethylene ultrathin film is provided with a conductive electrode.

[0031] It also includes an electrochemically active material.

[0032] The aforementioned skin sensor is used for the determination of physiological parameters on the skin surface.

[0033] Further, the aforementioned skin sensor is used as a temperature sensor, an ion concentration determination sensor, a blood pressure sensor, or an organic matter concentration determination sensor.

[0034] An application of an ultrahigh molecular weight polyethylene ultrathin film with a thickness of 50-1000nm, which is used as the base material of a skin sensor.

[0035] It includes the following steps:

[0036] (1) Take an ultrahigh molecular weight polyethylene ultrathin film with a thickness of 50-1000nm, wet the ultrahigh molecular weight polyethylene ultrathin film using an alcohol organic solvent, and expel the air inside the voids of the ultrahigh molecular weight polyethylene ultrathin film; then soak it in deionized water to achieve water solvation of the ultrahigh molecular weight polyethylene ultrathin film with a water contact angle of 30-90°, and immediately proceed to the next step after taking it out.

[0037] (2) A water-soluble mask layer is arranged on the surface of the water-solventized ultra-high molecular weight polyethylene ultra-thin film, and the water-soluble mask layer has a hollow shape; then the ultra-high molecular weight polyethylene ultra-thin film provided with the water-soluble mask layer is placed on a metal block, and a conductive electrode is prepared; in the process of preparing the conductive electrode, the metal block provides external support for the ultra-high molecular weight polyethylene ultra-thin film and leads out heat; finally, the ultra-high molecular weight polyethylene ultra-thin film after the preparation of the conductive electrode is placed in water, and after the water-soluble mask layer is separated from the ultra-high molecular weight polyethylene ultra-thin film, the ultra-high molecular weight polyethylene ultra-thin film provided with the conductive electrode is obtained, that is, a skin sensor. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a preparation flowchart of step (2) in the method of the present application; a: the water-soluble mask layer is placed on the surface of the PET temporary pad; b: the electrode circuit position is engraved on the water-soluble mask layer; c: the water-soluble mask layer with the electrode circuit position is attached to the surface of the LTM film; d: multiple magnetron sputtering to ensure the conductivity of the electrode circuit; e: dissolving and removing the water-soluble mask layer in water; f: loading electrochemically active substances on the electrode layer prepared by magnetron sputtering.

[0039] Figure 2 It is a schematic diagram of part of the macroscopic physical properties of the LTM ultra-thin film; a: a large-area self-supporting display diagram of the LTM ultra-thin film; b: based on a filtration device, a top view of the air permeability display of the LTM ultra-thin film; c: based on a filtration device, a top view of the water permeability display of the LTM ultra-thin film; d: a stability display diagram of the LTM ultra-thin film attached to the skin on the wrist; e: based on a filtration device, a side view of the air permeability display of the LTM ultra-thin film; f: based on a filtration device, a side view of the water permeability display of the LTM ultra-thin film; g: a skin self-attachment stability diagram of the LTM ultra-thin film after being washed by water flow.

[0040] Figure 3 The structure characterization diagram of the ultra-high molecular weight polyethylene ultra-thin film prepared by the present application is given; among them, a: a display diagram of the ultra-high molecular weight polyethylene ultra-thin film maintaining self-supporting and structural integrity under a large suspended area of 36 square centimeters; b: a photo of the ultra-high molecular weight polyethylene ultra-thin film attached to human skin, with a scale of 1 centimeter; c: an OM photo (i.e. optical crystal image photo) of the human skin replica (i.e. fine engraving silicone of human skin texture), focusing on the coverage boundary of the ultra-thin film on the skin model, the ultra-high molecular weight polyethylene ultra-thin film is marked in blue, and the scale is 200 microns; d: a scanning electron microscope (SEM) image of the LTM ultra-thin film; e: a transmission electron microscope (TEM) direct observation diagram of the ultra-high molecular weight polyethylene ultra-thin film on a TEM copper mesh, with a scale of 200 nanometers; f: an atomic force microscope (AFM) image of the LTM ultra-thin film, and the cross-sectional height profile is extracted along the white dashed line.

[0041] Figure 4 Schematic and characterization of sweat sensor, where (a): schematic shows that LTM film is comfortably attached to the skin surface of human and meanwhile detects target analytes in sweat, such as Na + , K + , Ca 2+ ions, glucose and temperature; (b): characterization of glucose sensing ability, inset shows the corresponding calibration curve; (c): characterization of Na + ion sensing ability, inset shows the corresponding calibration curve; (d): characterization of K + ion sensing ability, inset shows the corresponding calibration curve; (e): characterization of Ca 2+ ion sensing ability, inset shows the corresponding calibration curve; (f): characterization of temperature sensing ability, inset shows the corresponding calibration curve.

[0042] Figure 5 The determination chart of epidermal sensor prepared by the present application is given; wherein a: comfortable wearing of LTM-based sweat sensor on the forehead of human body; b: comfortable wearing of LTM-based sweat sensor on the back of the neck of human body; c: comfortable wearing of LTM-based sweat sensor on the upper arm of human body; d: wearable picture of LTM-based sweat sensor during fixed bicycle riding; e: real-time monitoring and analysis chart of sweat during exercise. DETAILED DESCRIPTION

[0043] All features disclosed in this specification, and / or all steps of any methods disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0044] Any of the features disclosed in this specification, unless explicitly stated otherwise, may be replaced by alternative features serving the same, or a similar, purpose.

[0045] (I) Raw materials, equipment and process conditions

[0046] 1. Raw materials

[0047] Raw materials include: ultra-high molecular weight polyethylene (UHMWPE for short) resin, expanded solvent vaseline, expanded solvent mineral oil, hot hexachloroethane, acetone, decaline, metals (chromium, gold, platinum) required for magnetron sputtering method, electrochemically active materials (including PEDOT:PSS, etc.).

[0048] 2. Experimental equipment

[0049] Experimental equipment includes: double screw extruder, universal tensile testing system, vacuum magnetron sputtering equipment, sputtering target material.

[0050] The main components of the twin-screw extruder include a feeding port, twin screws, a barrel, and a discharging port. Among them, the twin screws are responsible for mixing and pushing the raw materials forward (specifically, the twin screws of the twin-screw extruder are responsible for thoroughly mixing and pushing the raw materials to ensure the uniformity of the gel film), and the barrel provides a heating and cooling environment, and the discharging port outputs the extruded gel film.

[0051] The main components of the universal tensile testing system include clamps, a stretching device, and a control system. Among them, the clamps are used to fix the gel film, the stretching device is responsible for stretching operation, and the control system controls the speed and number of stretching. In the universal tensile testing system, the stretching device is used to stretch the gel film to prepare an ultra-thin film, and the speed and number of stretching are controlled to obtain ideal film performance.

[0052] The main components of the vacuum magnetron sputtering device include a vacuum chamber, a sputtering target, a power supply, and a control system. The vacuum chamber is used to provide a vacuum environment; under the vacuum environment, the metal is deposited on the ultra-thin film through the sputtering target. The power supply is used to provide the energy required for sputtering, and the control system is used to control the sputtering process.

[0053] The sputtering target of the magnetron sputtering device is used to provide a metal source, and the metal is deposited on the ultra-thin film by sputtering to form an electrode.

[0054] 3. Process conditions

[0055] Temperature control: During the preparation process, the temperature of each stage is strictly controlled, such as the mixing temperature of UHMWPE and vaseline is 130℃, the aging treatment temperature is 125℃, and the temperature of solvent extraction and film drying is 60℃.

[0056] Environmental control: During the stretching and aging treatment stages, ensure that the conditions of the environmental chamber are stable to avoid external interference.

[0057] Solvent selection: Select hot hexachloroethane and acetone as the extraction solvent to ensure that the vaseline can be completely removed without affecting the performance of the ultra-thin film.

[0058] (II) Preparation of skin sensor

[0059] Example 1

[0060] In this example, an ultra-high molecular weight polyethylene ultra-thin film with a thickness of 200 nm is selected as the substrate material of the skin sensor, and the ultra-thin film is prepared by the method disclosed in CN113263747A.

[0061] The specific operation of preparing the skin sensor in this example is as follows.

[0062] (1) Select the thickness of 200 nm of ultra-high molecular weight polyethylene ultra-thin film, using alcohol organic solvent ethanol on the ultra-high molecular weight polyethylene ultra-thin film wetting, discharge the ultra-high molecular weight polyethylene ultra-thin film void inside the air. Before the alcohol organic solvent drying, the ultra-high molecular weight polyethylene ultra-thin film is soaked in 50℃ deionized water, the soaking time is 24 hours, after taking out immediately for the next step.

[0063] (2) the soaking treatment after the ultra-high molecular weight polyethylene ultra-thin film is taken out, the water-soluble mask layer is arranged on the surface of the ultra-high molecular weight polyethylene ultra-thin film. According to the electrode circuit requirement of the required sensor type, the water-soluble mask layer is cut out in advance on the water-soluble mask layer. Hollow shape, the water-soluble mask layer is attached to the ultra-high molecular weight polyethylene ultra-thin film. Then, using magnetron sputtering method on the ultra-high molecular weight polyethylene ultra-thin film covered with water-soluble mask layer, depositing conductive electrode.

[0064] The ultra-high molecular weight polyethylene ultra-thin film deposited with conductive electrode is placed in 20℃ deionized water for 5 minutes, after the glue in the water-soluble mask layer is completely dissolved, the mask layer is peeled off in water, and the ultra-high molecular weight polyethylene ultra-thin film is removed from the surface of the ultra-high molecular weight polyethylene ultra-thin film; again the ultra-high molecular weight polyethylene ultra-thin film is taken out from the water, and completely dried in the fume hood; at this time, the microcircuit has been built on the ultra-thin film. If using conventional operation, such as microelectronic printer printing, it will almost immediately lead to the rupture of the ultra-thin film, and the subsequent process cannot be completed (because during the printing process, the conductive gel material will introduce considerable deformation in the drying shrinkage process, and such conductive material itself is generally metal, which is much higher than the modulus of high molecular film (harder), causing the internal stress in the material to be released, finally leading to the rupture of the ultra-thin film). Finally, the electrochemically active material is arranged on the metal circuit layer, and the skin sensor is obtained, in which the ultra-high molecular weight polyethylene ultra-thin film, the conductive electrode and the electrochemically active material are connected in sequence from bottom to top.

[0065] In this embodiment, the water-soluble mask layer is in the form of single-sided tape. Before use, the water-soluble mask layer is placed on the PET temporary pad, as shown in Figure 1 , the electrode circuit shape is engraved according to the requirements of different sensors. After engraving, the protective film of the mask layer is torn off, exposing the water-soluble glue layer, which is attached to the polyethylene LTM ultra-thin film. Then magnetron sputtering is carried out to prepare the electrode circuit layer, and the electrochemically active substance is coated and dried. Then the whole device is immersed in water to dissolve the water-soluble mask layer. Then take out and dry.

[0066] Example 2

[0067] The existing flexible sensor has poor air permeability and biocompatibility, which leads to the fact that the sweat on the surface of the patient's skin cannot be effectively discharged, and the patient's skin is prone to allergic phenomena such as red rash after long-term wearing. The thickness of the ultrahigh molecular weight polyethylene ultra-thin film used in this embodiment is 100 nm, the porosity is 45%, and the pore diameter is 70 nm. The specific operation for preparing the skin sensor is as follows.

[0068] (1) Take the ultrahigh molecular weight polyethylene ultra-thin film, use the alcohol organic solvent ethanol to wet the ultrahigh molecular weight polyethylene ultra-thin film, and discharge the air inside the void of the ultrahigh molecular weight polyethylene ultra-thin film. Then soak it in deionized water, so that the water contact angle of the ultrahigh molecular weight polyethylene ultra-thin film reaches 81° to realize water solvation, and immediately take the next step after taking it out.

[0069] (2) A water-soluble mask layer is arranged on the surface of the water-solubilized ultrahigh molecular weight polyethylene ultra-thin film, and the water-soluble mask layer has a hollow shape. Place the ultrahigh molecular weight polyethylene ultra-thin film with the water-soluble mask layer on a metal block, and then use magnetron sputtering to prepare a conductive electrode. During the preparation of the conductive electrode, the metal block provides external support for the ultrahigh molecular weight polyethylene ultra-thin film and leads out the heat. After the preparation of the conductive electrode is completed, the ultrahigh molecular weight polyethylene ultra-thin film is placed in water, and after the water-soluble mask layer and the ultrahigh molecular weight polyethylene ultra-thin film are separated, the ultrahigh molecular weight polyethylene ultra-thin film with the conductive electrode on the surface is obtained, that is, the skin sensor.

[0070] Example 3

[0071] In this embodiment, the thickness of the ultrahigh molecular weight polyethylene ultra-thin film used as the base material is 150 nm, the Young's modulus is 0.5 GPa, and the strain is 10% or more. The orientation degree or strength: add more white oil, and use a higher stretching ratio during the stretching preparation process. The specific operation for preparing the skin sensor is as follows.

[0072] (1) Take the ultrahigh molecular weight polyethylene ultra-thin film, use the alcohol organic solvent ethanol to wet the ultrahigh molecular weight polyethylene ultra-thin film, and discharge the air inside the void of the ultrahigh molecular weight polyethylene ultra-thin film. Then soak it in deionized water, so that the water contact angle of the ultrahigh molecular weight polyethylene ultra-thin film reaches 81° to realize water solvation, and immediately take the next step after taking it out.

[0073] (2) A water-soluble mask layer is arranged on the surface of the water-solubilized ultra-high molecular weight polyethylene ultra-thin film, and the water-soluble mask layer has a hollow shape. The ultra-high molecular weight polyethylene ultra-thin film provided with the water-soluble mask layer is placed on a metal block, and then a magnetron sputtering is used to prepare a conductive electrode. During the preparation of the conductive electrode, the metal block provides external support for the ultra-high molecular weight polyethylene ultra-thin film and leads out heat. After the preparation of the conductive electrode is completed, the ultra-high molecular weight polyethylene ultra-thin film is placed in water, and after the water-soluble mask layer is separated from the ultra-high molecular weight polyethylene ultra-thin film, an ultra-high molecular weight polyethylene ultra-thin film provided with a conductive electrode on the surface, i.e., a skin sensor, is obtained.

[0074] Comparative Example 1

[0075] The thickness of the general thickness ultra-high molecular weight polyethylene ultra-thin film is between 10-50 μm. In this embodiment, a 25-micron-thick polyethylene porous diaphragm is used as the base material of the skin sensor, and the skin sensor is prepared according to the steps of Example 1.

[0076] The test results show that: using the water solubilization method in step (1) of Example 1 to treat the 25-micron-thick polyethylene porous diaphragm, because water cannot effectively wet the surface of the polyethylene thick film (i.e., the 25-micron-thick polyethylene porous diaphragm), this operation is almost ineffective on the polyethylene thick film, has only a weak effect on its water contact angle, and does not change its hydrophobic surface properties. If the 25-micron-thick polyethylene porous diaphragm is treated by plasma or the like, the mechanical properties of the polyethylene film will be significantly changed, making it brittle, which is not conducive to its subsequent application as a body surface flexible sensor. Therefore, when a general thickness ultra-high molecular weight polyethylene ultra-thin film is used as the base material to prepare a skin sensor, due to the lack of surface hydrophilic treatment and the fact that the roughness of the general thickness polyethylene film is much larger than that of the LTM ultra-thin film (at least one order of magnitude higher), the electrode circuit prepared by the subsequent mask-magnetron sputtering method or microelectronic printing method has poor continuity, low conductivity, and is easily damaged during wearing, leading to device failure.

[0077] Further, the 25-micron-thick polyethylene film is completely impermeable to water under normal pressure (zero flux after 72 hours) and almost impermeable to air, which cannot meet the requirement of "solving the problem of air and water permeability required for long-term wearing".

[0078] Finally, the 25-micron-thick polyethylene film does not have the high surface energy of the LTM ultra-thin film and the unique strong surface self-adaptation and self-adhesion performance of the ultra-thin film, and cannot be well adhered to the surface of the human skin, which cannot meet the requirement of "wearing without using additional fixing equipment".

[0079] Comparative Example 2

[0080] The present application cancels the metal block for providing external support and leading out heat when performing magnetron sputtering treatment, and other operations are the same as those in Example 1.

[0081] The specific operation process of magnetron sputtering is as follows.

[0082] (a) Pretreatment and preparation

[0083] Before sputtering, the ultra-high molecular weight polyethylene ultra-thin film is first cleaned to ensure that the surface is free of dust and grease. The ultra-high molecular weight polyethylene ultra-thin film after soaking treatment is taken out, and a water-soluble mask layer is arranged on the surface of the ultra-high molecular weight polyethylene ultra-thin film (specifically: the mask plate is cut according to the designed circuit pattern, and is accurately covered on the surface of the ultra-high molecular weight polyethylene ultra-thin film).

[0084] (b) Loading sample

[0085] The prepared ultra-high molecular weight polyethylene ultra-thin film and mask plate assembly are placed in the chamber of the magnetron sputtering machine, and no metal block is used as the bearing in the present comparative example.

[0086] (c) Vacuumizing treatment

[0087] The chamber of the magnetron sputtering machine is closed, and the vacuumizing system is started. The vacuum degree in the chamber is gradually increased to the predetermined sputtering working pressure, which is generally in the range of 3x10^-3 Torr to 5x10^-3 Torr.

[0088] (d) Preparation before sputtering

[0089] After reaching the required sputtering working pressure, the sputtering target is preheated. The target used in the present example is a gold (Au) target. The purpose of preheating is to remove impurities from the surface of the target and to stabilize the sputtering rate in advance.

[0090] (e) Sputtering process

[0091] The magnetron sputtering machine is started, and appropriate direct current power is applied to the gold target to start the sputtering process. According to the required gold film thickness and circuit design, the time and power of each round of sputtering are accurately controlled, and multiple rounds of sputtering operation are performed.

[0092] (f) Post-treatment

[0093] After the last round of sputtering is completed, the magnetron sputtering machine is turned off, and the pressure in the chamber is slowly increased to restore it to atmospheric pressure. After the pressure in the chamber is balanced, the polyethylene film is taken out.

[0094] The test results show that: after the water-solvent method in step (1) of Example 1 is used to treat the ultra-high molecular weight polyethylene ultra-thin film, if a metal block with the same size as the suspended part of the ultra-high molecular weight polyethylene ultra-thin film is not used as a support in sputtering, the gold nano-particle layer on the load of the multi-round magnetron sputtering will gradually accumulate internal stress. This is because heat is generated during the magnetron sputtering process, and because the material strength of gold and polyethylene is very different, during the cooling process of the previous round of metal particles, the next round of sputtering begins to generate heat. Thus, under the influence of complex stress field and temperature field, after multiple experiments, the magnetron sputtering can only be carried out for 3-6 rounds, and the ultra-high molecular weight polyethylene ultra-thin film will almost be completely broken.

[0095] Comparative Example 3

[0096] In this example, a common shield is used instead of the water-soluble mask layer in Example 1. The common shield can be metal, plastic, etc., and does not have glue on it. After depositing the conductive electrode, the common shield can be directly removed from the surface of the ultra-high molecular weight polyethylene ultra-thin film, and the rest is the same as Example 1.

[0097] The test results show that: if a common shield without glue is used instead of the water-soluble mask layer of the present application, it cannot guarantee that the common shield is tightly attached to the ultra-high molecular weight polyethylene ultra-thin film. In the multi-round gold particle magnetron sputtering, it cannot guarantee the shape and precise size of the microelectronic circuit, and the prepared circuit is usually much wider than the designed width, and in severe cases it can cause short circuit conduction between different circuits.

[0098] From Comparative Example 1, it can be found that when a general thickness of ultra-high molecular weight polyethylene ultra-thin film with a thickness of 10-50 μm is used as an extremely low material for a skin sensor, the preparation of the corresponding skin sensor cannot be realized, and the main reasons for the failure are as follows:

[0099] (1) The surface of the ultra-high molecular weight polyethylene ultra-thin film with a thickness of 10-50 μm is rough, and it is difficult to perform stable and deep surface hydrophilic modification using the water-solvent method of the present application. Using other modification methods will also reduce the mechanical strength to some extent; this makes it very difficult to use printing or the mask-sputtering method in Example 1 to prepare electrode circuits on it, and the final effect is very unsatisfactory;

[0100] (2) The final product prepared in Comparative Example 1 is difficult to self-attach to the surface of the human skin, and is completely water-impermeable and almost completely air-impermeable.

[0101] In the present application, the 50-1000 nm ultra-high molecular weight polyethylene ultra-thin film is treated by immersion in an alcohol organic solvent, so that the water contact angle of the ultra-high molecular weight polyethylene ultra-thin film reaches 30-90° to achieve water solvation. For general thickness of ultra-high molecular weight polyethylene film, because the material is inherently hydrophobic and the thickness is large, even if the operation in the present application is used, the same effect is difficult to achieve. However, the ultra-thin film used in the present application can be uniformly and completely wetted by the organic solvent, and during the subsequent long-time water immersion, a certain degree of solvation phenomenon is achieved - after the ultra-thin film is taken out of the water, it can be temporarily hydrophilic and water can be stored in the internal void for one hour or more. This is very important for the requirements of high toughness, high thermal conductivity and other requirements in subsequent processes, and can maintain the structural integrity of the ultra-thin film.

[0102] From Comparative Example 2, it can be found that, unlike Example 1, when the metal block for providing external support and dissipating heat is removed, the gold nanoparticle layer on the multi-wheel magnetron sputtering load will gradually accumulate internal stress, and after several experiments, the magnetron sputtering can only be carried out for 3-6 rounds, and the ultra-high molecular weight polyethylene ultra-thin film will be almost completely broken.

[0103] Step (2) is one of the difficulties of the present application, because unlike other conventional thickness of polymer film, the 50-1000 nm ultra-high molecular weight polyethylene ultra-thin film is relatively weak in absolute value of mechanical strength, and the kinetic energy of metal particles and the heat generated during magnetron sputtering will directly destroy the macroscopic integrity of the ultra-thin film; therefore, during the sputtering process, the following adjustments are made innovatively: using a metal block with the same shape and size as the suspended area of the ultra-high molecular weight polyethylene ultra-thin film, keeping the surface smooth and flat, and placing it under the ultra-high molecular weight polyethylene ultra-thin film; so that during the entire controlled sputtering process, the metal block provides external mechanical support for the ultra-thin film and efficiently dissipates heat, preventing the ultra-thin film from breaking due to uneven local heating or stress concentration.

[0104] The present application successfully prepares an ultra-thin polymer LTM with excellent performance, and based on it, microelectronic circuits and sensor devices are assembled under the premise of maintaining its high self-supporting, and a skin sensor is successfully prepared and applied in the preparation of wearable sensors. The skin sensor of the present application is a skin sensor that can realize distributed, reactive and tracking medical care, and provides a basis for real-time, personalized health monitoring. The technical scheme and experimental process of the present application have operability and repeatability, and can meet the needs of industrialized mass production and application.

[0105] The skin sensor of the present application has a thickness at the nanometer level and excellent air and water permeability, effectively avoiding skin problems caused by long-term wearing of existing sensors. The integrated skin sensor based on ultra-thin polymer of the present application realizes the functions of transparency, self-adaptation, air permeability / hydration, has good wearability and comfortable feeling, and provides a new solution for non-inflammatory, long-term stable electronic-tissue interface design. Test results show that the sensor can effectively solve the problems of skin damage such as dermatitis caused by long-term wearing of water and oxygen isolation, and the difficulties of smart device fixation and wearing, realize the unity of physiological adaptability and physical adhesion, and promote the development of wearable medical treatment. At the same time, the sensor has the characteristics of high sensitivity, high selectivity and stability, and can provide strong support for the prevention, monitoring and treatment of diseases.

[0106] (III) Sample testing

[0107] The present application integrates three types of sensors (i.e. three types of sensors are arranged on the same high molecular weight polyethylene ultra-thin film, the porosity thereof is 30-70%, and the pore diameter is 10-200 nm) on the high molecular weight polyethylene ultra-thin film, and the signals of five channels: temperature, sweat glucose concentration, and sodium, potassium and calcium ion concentrations.

[0108] 1. Temperature sensor using platinum (Pt) electrode

[0109] A platinum electrode is fabricated on the ultra-thin film substrate by sputtering, creating a pattern that effectively forms a resistance temperature detector (RTD). The overall size of the sensor is 3 cm x 4 cm, and the width of the platinum electrode is 0.5 mm and the length is 3 cm to improve sensitivity. The platinum electrode is usually designed in a serpentine or coil pattern to maximize the surface area, improve sensitivity and accuracy. A layer of about 1 μm thick insulating material is applied to cover the electrode, leaving openings at the ends of the electrode for connecting wires. The working principle of the platinum RTD is that the change of resistance of platinum with temperature is predictable. As the temperature rises, the resistance of the platinum electrode increases linearly, and this resistance change is measured by a Wheatstone bridge circuit or similar configuration. The temperature is determined by measuring the resistance and applying the known temperature coefficient (TCR) of platinum, i.e. about 0.00385 Ω / Ω / ℃ of the standard sensor.

[0110] 2. Glucose sensor

[0111] The electrochemically active material of the glucose sensor comprises two layers: an enzyme layer and an electron mediator layer, coated on a metal circuit layer. The enzyme layer contains glucose oxidase (GOx) immobilized on the surface of the metal circuit layer by techniques such as drop casting, spin coating or electropolymerization. Below the enzyme layer, the electron mediator layer facilitates the transfer of electrons generated in the enzymatic reaction to the metal circuit layer. Common mediators include iron cyanide derivatives or Prussian blue. The glucose sensor is based on the enzymatic oxidation of glucose, which produces gluconolactone and hydrogen peroxide (H2O2) by glucose oxidase. The electron mediator layer transfers the electrons of H2O2 produced in the enzymatic reaction to the electrode, generating an electric current proportional to the glucose concentration. The measured current is then correlated to the glucose concentration in sweat, allowing its quantitative analysis. Specifically: a layer of electron mediator (such as iron cyanide derivative) is first coated by spin coating, with a thickness of about 100 nanometers; then, on the electron mediator layer, a solution of immobilized glucose oxidase is added by drop casting, and dried to form an enzyme layer, with a thickness of about 200-300 nanometers.

[0112] 3. Na + , K + , Ca 2+ ion sensor

[0113] The electrochemically active material of the ion-selective sensor also involves two layers: an ion-selective membrane layer, and a conductive polymer layer (such as PEDOT:PSS). The ion-selective membrane contains specific ionophores that selectively bind Na + , K + or Ca 2+ ions, and this layer can be applied by drop casting or spin coating. The PEDOT:PSS layer acts as a conductive electrode, facilitating the conversion of ionic current to an electronic signal. The ion-selective membrane layer responds to changes in the concentration of specific ions (Na + , K + , Ca 2+ ) by changing its potential; this change in potential alters the current through the conductive PEDOT:PSS layer, which can be measured by a reference electrode. The change in current or potential is directly related to the ion concentration, allowing the quantitative measurement of the concentration of the corresponding ion in sweat.

[0114] The specific operation of one example is as follows: based on an ultra-high molecular weight polyethylene ultra-thin film with a metal conductive electrode arranged on the surface, a PEDOT:PSS conductive layer is formed on the metal conductive electrode by a spin coating method, and the thickness is about 100 nanometers. Then, according to the target ion species, the corresponding ion-selective membrane is coated. The ion-selective membrane is prepared by dissolving a specific ion carrier and a polymer matrix (such as PVC) in a solvent and coating on the PEDOT:PSS layer by drop coating, and the thickness is about 200-500 nanometers. Each ion sensor region is separated from other sensor regions by an insulating layer to avoid signal interference.

[0115] Figure 2 Some key macroscopic physical property display figures of the ultra-high molecular weight polyethylene ultra-thin film prepared by the present application are given. Figure 2 a gives a large-area suspended self-supporting display of the LTM ultra-thin film, and also has considerable mechanical strength and toughness (macroscopic deformation caused by fingers directly). Figure 2 b and Figure 2 e are a group for displaying the air permeability of the LTM ultra-thin film in the present application. Among them, Figure 2 b is an air permeability display top view of the LTM ultra-thin film based on a suction device; Figure 2 e is an air permeability display side view of the LTM ultra-thin film based on a suction device; as shown in the figure, based on the suction device, but instead of vacuum suction, argon is pumped into the suction cup, and it can be seen that argon passes through the polyethylene LTM ultra-thin film at a high flux.

[0116] Figure 2 c and Figure 2 f are a group for displaying the water permeability of the LTM ultra-thin film in the present application. Among them, Figure 2 c is a water permeability display top view of the LTM ultra-thin film based on a suction device; Figure 2 f is a water permeability display side view of the LTM ultra-thin film based on a suction device; as shown in the figure, based on the same suction system, the standard vacuum suction method is used to accelerate the display of the water permeability of the LTM ultra-thin film. For the normally hydrophobic polyethylene film, without going through the complicated hydrophilic surface treatment process, it will not be water permeable under a negative pressure of only 0.3 bar. However, as shown in the figure, under a negative pressure of 0.3 bar, the water dyed in the figure passes through the LTM ultra-thin film at a high flux, which displays the water permeability of the LTM. The LTM ultra-thin film will also be water permeable under normal pressure, but the flux will be lower. For the secretion rate of sweat, such water permeability is sufficient to allow sweat to pass through the LTM ultra-thin film without accumulating between the LTM and the skin.

[0117] Figure 2d is the stability of LTM ultra-thin film adhering to the skin of the wrist, which deforms and bends closely to the skin during wrist movements such as stretching or shrinking, and does not produce phenomena such as separation. Figure 2 g demonstrates the excellent skin self-adhesion stability of LTM ultra-thin film with water permeability: even under continuous flushing of pressurized water for five minutes, there is almost no desorption. This demonstrates the excellent anti-sweat and anti-water flow interference performance of LTM ultra-thin film during long-term wear on the body surface, ensuring the long-term and high-level realization of its self-adhesion performance.

[0118] Figure 3 The structural characterization figure of the ultra-high molecular weight polyethylene ultra-thin film prepared by the present application is given. Figure 3 a is the demonstration of the self-supporting and structural integrity of LTM ultra-thin film under a large suspended area of 36 square centimeters. Figure 3 b is a photo of the ultra-high molecular weight polyethylene ultra-thin film adhering to human skin, Figure 3 c gives the OM photo of the human skin replica (fine texture replication silicone rubber) adhering to the human skin, and the LTM ultra-thin film can adhere to the human skin texture to a very high degree, which is the mechanism of the LTM self-adhesion performance. Figure 3 d gives the scanning electron microscope (SEM) image of the LTM ultra-thin film. Figure 3 e gives the direct observation figure of the transmission electron microscope (TEM) of the ultra-high molecular weight polyethylene ultra-thin film on the TEM copper mesh. Generally, polyethylene film cannot be directly observed by TEM without surface metal evaporation treatment; the main reason is that the electron beam cannot penetrate the polyethylene film due to its too large thickness, and effective TEM observation cannot be performed. Discharge phenomenon caused by surface charge accumulation, and electron beam with acceleration voltage above 200 kilovolts, may also directly damage the microstructure of the polyethylene film. The LTM ultra-thin film has a tensile modulus of more than 10 GPa due to the use of ultra-high bidirectional stretching ratio and the high orientation of molecular chains, which is more than ten times the modulus of general polyethylene film. Figure 3 f gives the atomic force microscope (AFM) image of the LTM ultra-thin film, which can be seen that the ultra-thin thickness of LTM is more than 20 times thinner than the thinnest polyethylene film on the market.

[0119] Figure 4 The schematic diagram and characterization figure of the sweat sensor are given, wherein, Figure 4 (a): the schematic diagram shows that the LTM film is comfortably adhered to the surface of human skin, and at the same time detects target analytes in sweat, such as Na + , K + , Ca 2+ ions, glucose and temperature; Figure 4 (b)– Figure 4 (f) respectively characterize glucose, Na+ , K + , Ca 2+ ions and temperature sensing capability. The insets show the corresponding calibration curves, respectively.

[0120] In the present application, the water vapor flux of the prepared ultra-high molecular weight polyethylene ultra-thin film reaches 10 kg per square meter per hour.

[0121] Figure 5 The determination graph of the prepared skin sensor is given. Figure 5 In the present application, a: comfortable wearing of the LTM-based sweat sensor on the forehead of a human body; b: comfortable wearing of the LTM-based sweat sensor on the back of the neck of a human body; c: comfortable wearing of the LTM-based sweat sensor on the upper arm of a human body; d: a picture showing the wearability of the LTM-based sweat sensor when riding a stationary bicycle; e: a real-time monitoring and analysis graph of sweat during exercise. The prepared LTM-based sweat sensor was subjected to long-time wearing test, and the average wearing time was 7 days. The test results showed that, under the condition of 7-day 24-hour continuous wearing, as long as no surfactant was used for washing, more than 90% of the ultra-thin sweat sensor maintained long-term wearing and sweat monitoring at different wearing positions (such as the back of the neck and the outer side of the arm) of the wearer. During the wearing process, on the one hand, the normal body movements of the wearer and the like did not have obvious influence on the adhesion and function of the ultra-thin sensor, and no problems such as detachment occurred; on the other hand, the user felt comfortable, and no allergic phenomena such as skin rash occurred, and the ultra-thin sensor also did not show irritability to the human skin during long-term wearing. The "two-way disturbance-free" between the human body and the ultra-thin sensor ensured the long-time ultra-low irritability wearing performance. The test results showed that the skin sensor of the present application could meet the requirement of long-time wearing, and maintained long-time collection and monitoring of the biological information of the body surface sweat without causing skin swelling, inflammation or other types of discomfort.

[0122] In summary, in the preparation of the ultra-thin film, the present application realizes the processing of the meter-level ultra-thin porous structure of the ultra-high molecular weight polyethylene (UHMWPE), breaks through the trade-off effect of the ultra-thin polymer, and realizes the unity of high compliance and comfort. Specifically, the present application innovatively uses a top-down method to process the UHMWPE, thereby obtaining a thin sheet with a large area, and breaks through the trade-off effect of the ultra-thin polymer. The prepared LTM (i.e. large thin sheet film) is independent, porous, and biaxially stable, while maintaining excellent structural integrity and robustness, and realizing the unity of high compliance and comfort. In the present application, a low melt blending temperature (the melt blending temperature is only about 130°C) is used, and no annealing operation is required, the reaction conditions are mild, the process flow is short, the operation is simple, and the production cost is low, which is conducive to the production and manufacturing of the skin sensor.

[0123] Then, on the basis of the ultra-thin film, a wearable skin sensor is prepared. The integrated sensor prepared on the LTM can characterize a plurality of ions, glucose and temperature in real time, has good selectivity, can work independently, and the cross talk between each other is negligible, which is crucial for integrated wearable sensors. At the same time, the integrated skin sensor has excellent air and water permeability, which helps to reduce skin temperature and keep the skin dry, solves the problem of skin damage such as dermatitis caused by long-term isolation of water and oxygen, and can non-invasively, continuously and / or intermittently monitor.

[0124] The ultra-thin porous UHMWPE material and the skin sensor prepared therefrom have breakthrough performance, such as the ultra-thin porous UHMWPE material having a meter-level ultra-thin porous structure, high compliance and comfort, excellent structural integrity and robustness, highly porous properties, good selectivity and stability, etc., which are difficult to achieve in the prior art. The improvement of these performances provides strong support for the realization of wearable medical treatment and real-time, personalized health monitoring, and belongs to qualitative improvement. The present application has very high practical value and social benefits, and is expected to promote the development of wearable medical treatment and real-time, personalized health monitoring.

[0125] The present application is not limited to the foregoing specific embodiments. The present application extends to any novel one, or any new combination, of the characteristics disclosed in this specification, as well as to any novel method or process disclosed in any of the steps or any new combination.

Claims

1. A method for preparing an epidermal sensor, characterized in that, Includes the following steps: (1) Take an ultra-high molecular weight polyethylene ultrafilm with a thickness of 50-1000nm, wet the ultra-high molecular weight polyethylene ultrafilm with an alcohol organic solvent to remove the air inside the pores of the ultra-high molecular weight polyethylene ultrafilm; then soak it in deionized water to make the water contact angle of the ultra-high molecular weight polyethylene ultrafilm reach 30-90° to achieve water solubilization, and take it out immediately to proceed to the next step. (2) A water-soluble mask layer is set on the surface of the water-solubilized ultra-high molecular weight polyethylene ultra-thin film, and a hollow shape is set on the water-soluble mask layer; then the ultra-high molecular weight polyethylene ultra-thin film with the water-soluble mask layer is placed on a metal block, and then the conductive electrode is prepared; finally, the ultra-high molecular weight polyethylene ultra-thin film after the conductive electrode is prepared is placed in water, and after the water-soluble mask layer separates from the ultra-high molecular weight polyethylene ultra-thin film, an ultra-high molecular weight polyethylene ultra-thin film with conductive electrodes on its surface is obtained, i.e., the skin sensor.

2. The preparation method according to claim 1, characterized in that, It also includes the following steps: (3) After obtaining an ultra-high molecular weight polyethylene ultrafilm with conductive electrodes on its surface, an electrochemically active material is placed on the surface to obtain an epidermal sensor that integrates an ultra-high molecular weight polyethylene ultrafilm, conductive electrodes, and electrochemically active material.

3. The preparation method according to claim 2, characterized in that, The electrochemically active material is fixed on the metal circuit layer by deposition and coating.

4. The preparation method according to claim 1, characterized in that, In step (1), the porosity of the ultra-high molecular weight polyethylene ultrafilm is 30-70%, and the pore diameter is 10-200 nm.

5. The preparation method according to any one of claims 1 to 4, characterized in that, In step (2), the conductive electrode is prepared by magnetron sputtering.

6. A skin sensor, characterized in that, The epidermal sensor is prepared using the method described in any one of claims 1 to 5.

7. The epidermal sensor according to claim 6, characterized in that, It uses an ultra-high molecular weight polyethylene ultrafilm with a thickness of 50-1000 nm as the substrate material, and conductive electrodes are set on the ultra-high molecular weight polyethylene ultrafilm. Furthermore, the skin sensor also includes electrochemically active materials.

8. The application of the epidermal sensor prepared by the method according to any one of claims 1 to 5, characterized in that, The epidermal sensor was used to measure physiological parameters of the skin surface.

9. The application of a skin sensor according to claim 6, characterized in that, The aforementioned skin sensor can be used as a temperature sensor, ion concentration sensor, blood pressure sensor, or organic matter concentration sensor.

10. An application of an ultra-high molecular weight polyethylene ultrafilm, characterized in that, The ultra-high molecular weight polyethylene ultrafilm has a thickness of 50-1000 nm and is used as the substrate material for the skin sensor. Includes the following steps: (1) Take an ultra-high molecular weight polyethylene ultrafilm with a thickness of 50-1000nm, wet the ultra-high molecular weight polyethylene ultrafilm with an alcohol organic solvent to remove the air inside the pores of the ultra-high molecular weight polyethylene ultrafilm; then soak it in deionized water to make the water contact angle of the ultra-high molecular weight polyethylene ultrafilm reach 30-90° to achieve water solubilization, and take it out immediately to proceed to the next step. (2) A water-soluble mask layer is set on the surface of the water-solubilized ultra-high molecular weight polyethylene ultra-thin film, and a hollow shape is set on the water-soluble mask layer; then the ultra-high molecular weight polyethylene ultra-thin film with the water-soluble mask layer is placed on a metal block, and then the conductive electrode is prepared; finally, the ultra-high molecular weight polyethylene ultra-thin film after the conductive electrode is prepared is placed in water, and after the water-soluble mask layer separates from the ultra-high molecular weight polyethylene ultra-thin film, an ultra-high molecular weight polyethylene ultra-thin film with conductive electrodes on its surface is obtained, i.e., the skin sensor.

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