阅读说明：本技术 可穿戴汗液传感器、其制备方法及应用 (Wearable sweat sensor, preparation method and application thereof ) 是由 王书琪 张珽 刘梦愿 杨显青 陆骐峰 李连辉 于 2021-08-16 设计创作，主要内容包括：本发明公开了一种可穿戴汗液传感器、其制备方法及应用。所述可穿戴汗液传感器包括吸汗机构,其在吸收不同体积的汗液时能产生不同程度的形变；传感机构,其用于监测所述吸汗机构在吸收汗液后的形变程度并产生相应的传感信号。本发明将汗液出汗量和出汗速率信息转换为实时连续的力学传感信号,利用力学传感机制对单位皮肤面积的宽范围出汗量和出汗速率进行实时监测,同时可对人体不同区域的出汗速率和出汗量进行快速、准确的测试和数据分析,对建立人体汗液数据库有重要意义。(The invention discloses a wearable sweat sensor, a preparation method and application thereof. The wearable sweat sensor includes a sweat absorbing mechanism that is capable of varying degrees of deformation upon absorption of varying volumes of sweat; and the sensing mechanism is used for monitoring the deformation degree of the sweat absorbing mechanism after absorbing sweat and generating a corresponding sensing signal. The invention converts sweat perspiration amount and perspiration rate information into real-time continuous mechanical sensing signals, utilizes a mechanical sensing mechanism to monitor the perspiration amount and perspiration rate in a wide range of unit skin area in real time, can quickly and accurately test and analyze the perspiration rate and perspiration amount of different areas of a human body, and has important significance for establishing a human body sweat database.)

1. A wearable sweat sensor for sweat volume and sweat rate detection, comprising:

the sweat absorbing mechanism can generate deformation of different degrees when absorbing sweat of different volumes;

and the sensing mechanism is used for monitoring the deformation degree of the sweat absorbing mechanism after absorbing sweat and generating a corresponding sensing signal.

2. The wearable sweat sensor of claim 1, wherein the sweat absorbing mechanism includes a sweat absorbing expansion block capable of continuously absorbing sweat secreted from the skin surface and producing a volume expansion in real time; the volume expansion amount of the sweat absorbing expansion block is positively correlated with the volume of sweat absorbed by the sweat absorbing expansion block, and the volume expansion speed is positively correlated with the volume of sweat absorbed in unit time.

3. The wearable sweat sensor of claim 2, wherein the sensing mechanism includes a strain sensor, and wherein the sweat-absorbing expansion block is capable of causing the strain sensor to deform to different extents upon absorption of different volumes of sweat, thereby causing the strain sensor to generate a corresponding sensing signal;

the deformation quantity of the strain sensor is positively correlated with the volume expansion quantity of the sweat-absorbing expansion block, and the deformation rate is positively correlated with the volume expansion speed of the sweat-absorbing expansion block.

4. The wearable sweat sensor of claim 3, wherein the sweat absorbing expansion block is film-like; and/or the strain sensor adopts a strain sensitive film sensor.

5. The wearable sweat sensor of claim 4, wherein the sensing mechanism is a strain sensing layer disposed within the strain sensing layer and in contact with a sweat-absorbing expansion block that is capable of pushing against the strain sensor as it expands absorbing sweat.

6. The wearable sweat sensor of claim 5, wherein the strain sensing layer comprises an insulating fixing layer having a window formed therein, wherein the strain sensor is fixedly disposed within the insulating fixing layer and partially exposed through the window, and wherein the sweat-absorbing expansion block is in contact with the partially exposed portion of the strain sensor through the window.

7. The wearable sweat sensor of claim 6, wherein the insulating fixing layer comprises a first insulating fixing layer and a second insulating fixing layer sequentially arranged in a direction away from the skin, the first insulating fixing layer and the second insulating fixing layer are respectively provided with a first opening and a second opening, the first opening and the second opening are matched to form the window, and the strain sensor is fixedly arranged between the first insulating fixing layer and the second insulating fixing layer;

preferably, the first insulating fixing layer and the second insulating fixing layer are made of polydimethylsiloxane elastic films;

preferably, the thickness of the first insulating fixed layer and the second insulating fixed layer is 0.1-3 mm.

8. The wearable sweat sensor of claim 7, wherein the central axes of the first and second openings coincide; and/or the sweat absorbing expansion block is arranged in the first opening; and/or the sweat-absorbent expanded block has the same diameter as the first opening; and/or the thickness of the sweat-absorbing expansion block is the same as that of the first insulating fixing layer.

9. The wearable sweat sensor of claim 6, further comprising an adhesive layer coupled to the strain sensing layer for conforming the wearable sweat sensor to a skin surface.

10. The wearable sweat sensor of claim 9 wherein a third opening is provided in the adhesive layer to expose the sweat absorbing intumescent mass to the skin.

11. The wearable sweat sensor of claim 4 where the sweat-absorbent expansion block comprises a porous membrane carrier loaded with a super-absorbent polymer or a porous membrane structure formed primarily of a super-absorbent polymer; preferably, the superabsorbent polymer comprises particles, powder or fibers of sodium polyacrylate; preferably, the sweat-absorbent swelling block further comprises a pH-responsive dye molecule; preferably, the thickness of the sweat-absorbing expansion block is 0.5-3 mm.

12. The wearable sweat sensor of claim 4 where the strain sensitive thin film sensor includes a superhydrophobic superelastic low modulus substrate and conductive nanomaterials distributed within the substrate or overlying the substrate surface; preferably, the material of the substrate comprises any one or more of thermoplastic elastomer, thermoplastic polyurethane, polydimethylsiloxane and silica gel; preferably, the conductive nanomaterial comprises any one of a carbon nanotube, graphene, a silver nanowire, a metal nanowire and a metal nano-film; preferably, the thickness of the strain sensitive thin film sensor is 50-150 nm.

13. The wearable sweat sensor of claim 1, wherein the sweat absorbing mechanism and the sensing mechanism are each multiple and arranged in an array; and/or, the wearable sweat sensor is a flexible device.

14. An apparatus for detecting an amount of perspiration and a rate of perspiration, comprising:

at least one wearable sweat sensor of any of claims 1-3; and

and the sweat signal acquisition and processing device is connected with the wearable sweat sensor and is used for continuously acquiring and analyzing the sensing signal output by the wearable sweat sensor.

15. The apparatus for detecting an amount and rate of perspiration according to claim 14,

comprises a sensor array comprising a plurality of wearable sweat sensors arranged in an array;

preferably, the plurality of wearable sweat sensors are arranged in a cascade.

16. A method of manufacturing a wearable sweat sensor for sweat volume and rate detection as claimed in any one of claims 1-13 comprising: respectively manufacturing a strain sensor and a sweat absorption expansion block, and enabling the sweat absorption expansion block to be in contact with the strain sensor.

17. The method according to claim 16, comprising:

respectively preparing a first insulating fixed layer and a second insulating fixed layer, and respectively forming a first opening and a second opening on the first insulating fixed layer and the second insulating fixed layer;

manufacturing a strain sensor, and fixedly arranging the strain sensor between the first insulating fixed layer and the second insulating fixed layer to form a strain sensing layer;

manufacturing a sweat absorption expansion block, and connecting the sweat absorption expansion block with a strain sensing layer;

the adhesive layer is attached to the strain sensing layer and the sweat-absorbent swelling mass is exposed to the skin from a third opening provided on the adhesive layer.

18. The method of claim 16, further comprising:

dispersing the constituent materials of the super-hydrophobic super-elastic low-modulus substrate and the conductive nano material in an organic solvent to form precursor liquid, and then preparing the precursor liquid into a thin film to form a strain sensitive thin film sensor;

or preparing a super-hydrophobic super-elastic low-modulus substrate, and coating the surface of the substrate with the dispersion liquid of the conductive nano material to form the strain sensitive film sensor;

preferably, the concentration of the conductive nano material dispersion liquid is 1-10 mg/mL; and/or the thickness of the super-hydrophobic super-elastic low-modulus film is 0.1-1 mu m.

19. The method for preparing an expanded block according to claim 16, wherein the method for preparing an expanded block specifically comprises:

uniformly and dispersedly attaching a high water-absorbing polymer material on a non-woven fabric film, and covering a layer of non-woven fabric film on the high water-absorbing polymer material to form a sweat-absorbing expansion block in a film form;

alternatively, the high water-absorbing polymer material is prepared into the sweat-absorbing expansion block in a film form by a dry mechanical reinforcement method or a hot melt adhesive bonding method.

20. A method of detecting perspiration volume and rate, comprising:

conforming the wearable sweat sensor of any of claims 1-13 to a selected skin surface area;

and continuously collecting and analyzing the sensing signals output by the wearable sweat sensor, so as to realize the detection of the sweat amount and the sweat rate in the selected skin surface area.

Technical Field

The invention belongs to the technical field of wearable equipment, and particularly relates to a wearable sweat sensor for detecting sweat amount and sweat rate, and a preparation method and application thereof.

Background

The detection of the components, the sweating amount and the sweating rate of the human body sweat is important research content of the wearable sensor, and is also a key technology for researching the relationship between the sweat and the health state and the disease of the human body. Wherein, the accurate detection of sweat volume and sweat rate is the basis of wearable sweat sensor research and application, and the main reasons include: (1) the rate and amount of sweating is related to the intensity of human movement, health status, disease, individual differences, and the like. For example, there is a correlation between core temperature and perspiration rate for thermal adaptation and aerobic exercise; there is a significant difference in the rate of sweating when exercising at high temperatures between the elderly and the young, as the sweat gland function changes with age, and hypovolemia may reduce the sensitivity to sweating; there is a strong correlation between the amount of sweating and the short-term dramatic changes in the rate of sweating and the state and ability of the exercise. (2) Changes in the rate of perspiration affect the detection of the composition of the perspiration. The rate of sweating affects the reabsorption of electrolyte ions, such as sodium ions, and there is a direct relationship between the rate of sweating and the final sweating concentrations of sodium and chloride ions; the detected concentration of different sweat components changes as a function of the rate of sweating. Therefore, in order to realize accurate detection of sweat components by the wearable sweat sensor and research and establish significance of correlation of sweat components, sweat amount and sweat rate with sports, health, diseases and the like, the wearable sensor and the device for sweat amount and sweat rate have very important research and development values.

At present, the principle of wearable sweat sensing technology for detecting sweat amount and sweat rate is mainly based on a method of a micro-fluidic chip attached to the surface of skin. Namely, sweat passively flows into the micro-channel, the sweat amount is directly and visually read out through the filling length and volume of the sweat in the micro-channel, or a parallel conductive electrode is arranged in the micro-channel to monitor the resistance change of the sweat, and then the sweat amount and the sweat speed are indirectly detected through a certain calibration method. However, this method of micro flow channel puts high demands on the preparation of micro flow channel chip, and the efficiency of sweat flowing into the micro flow channel is also problematic; meanwhile, the new sweat and the old sweat flow into the same micro-flow channel to cause the new sweat and the old sweat to be mixed, so that the concentration of the new sweat and the old sweat is changed and the measurement of the sweat resistance is influenced.

Therefore, the method and the device adopted by the prior art have the advantages of complex preparation, high cost, low sweat collection efficiency and limited sweat collection amount, and meanwhile, the detection signal is limited by the interference of sweat concentration change, so that the sweat amount, the sweat rate and the electrolyte concentration cannot be accurately distinguished and detected.

Disclosure of Invention

It is a primary object of the present invention to provide a wearable sweat sensor and device for sweat volume and rate detection that solves the problems of the prior art.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

embodiments of the present invention provide a wearable sweat sensor for sweat volume and sweat rate detection, comprising:

the sweat absorbing mechanism can generate deformation of different degrees when absorbing sweat of different volumes;

and the sensing mechanism is used for monitoring the deformation degree of the sweat absorbing mechanism after absorbing sweat and generating a corresponding sensing signal.

Further, the sweat absorbing mechanism comprises a sweat absorbing expansion block, the sweat absorbing expansion block can continuously absorb sweat secreted from the surface of the skin in real time and generate volume expansion, the volume expansion amount of the sweat absorbing expansion block is positively correlated with the volume of the sweat absorbed by the sweat absorbing expansion block, and the volume expansion speed is positively correlated with the volume of the sweat absorbed in unit time.

Further, the sensing mechanism comprises a strain sensor, and the sweat absorbing expansion block can drive the strain sensor to generate different degrees of deformation after absorbing sweat with different volumes, so that the strain sensor generates corresponding sensing signals;

the deformation quantity of the strain sensor is positively correlated with the volume expansion quantity of the sweat-absorbing expansion block, and the deformation rate is positively correlated with the volume expansion speed of the sweat-absorbing expansion block.

Embodiments of the present invention also provide an apparatus for detecting an amount of perspiration and a rate of perspiration, including:

at least one wearable sweat sensor as described above; and

and the sweat signal acquisition and processing device is connected with the wearable sweat sensor and is used for continuously acquiring and analyzing the sensing signal output by the wearable sweat sensor.

Further, the device includes a sensor array comprising a plurality of wearable sweat sensors arranged in an array.

Preferably, the plurality of wearable sweat sensors are arranged in a cascade.

An embodiment of the present invention further provides a method for manufacturing the wearable sweat sensor for detecting sweat amount and sweat rate, including:

respectively preparing a first insulating fixed layer and a second insulating fixed layer, and respectively forming a first opening and a second opening on the first insulating fixed layer and the second insulating fixed layer;

manufacturing a strain sensor, and fixedly arranging the strain sensor between the first insulating fixed layer and the second insulating fixed layer to form a strain sensing layer;

manufacturing a sweat absorption expansion block, and connecting the sweat absorption expansion block with a strain sensing layer;

the adhesive layer is attached to the strain sensing layer and the sweat-absorbent swelling mass is exposed to the skin from a third opening provided on the adhesive layer.

Further, the strain sensor is a super-hydrophobic superelasticity low-modulus strain sensitive thin-film sensor, and the preparation method of the strain sensitive thin-film sensor specifically comprises the following steps:

dissolving a super-hydrophobic super-elastic low-modulus substrate material and a conductive nano material in an organic solvent in sequence according to a proportion to form a homogeneous solution, and preparing the homogeneous solution into a film with a certain thickness by a spraying or spin coating method to form a strain sensitive film sensor;

or dissolving a super-hydrophobic super-elastic low-modulus substrate material in an organic solvent to obtain a thermoplastic elastomer solution, preparing a super-hydrophobic super-elastic low-modulus film with a certain thickness from the thermoplastic elastomer solution by a spin coating or bubble blowing method, and preparing a strain sensitive film on the film by a spraying method from a dispersion liquid of a conductive nano material to form a strain sensitive film sensor;

and adhering conductive cloth on the surface of the prepared strain sensor to form an electrode, and leading part of the electrode out of the surface of the strain sensor.

Further, the preparation method specifically comprises the following steps:

dispersing the composition materials of the super-hydrophobic super-elastic low-modulus substrate and the conductive nano material in an organic solvent to form a homogeneous solution, and then preparing the homogeneous solution into a thin film to form a strain sensitive thin film sensor;

or preparing a super-hydrophobic super-elastic low-modulus substrate, and coating the surface of the substrate with the dispersion liquid of the conductive nano material to form the strain sensitive film sensor.

Further, the preparation method of the expansion block specifically comprises the following steps:

uniformly and dispersedly attaching a high water-absorption polymer material on a non-woven fabric film, and covering a layer of non-woven fabric film on the high water-absorption polymer material to form a film-shaped expansion block;

or, the high water absorption polymer material is prepared into the film-shaped expansion block by a dry mechanical reinforcing method or a hot melt adhesive bonding method.

The embodiment of the invention also provides a sweat amount and sweat rate detection method, which comprises the following steps:

applying the wearable sweat sensor to a selected skin surface area;

and continuously collecting and analyzing the sensing signals output by the wearable sweat sensor, so as to realize the detection of the sweat amount and the sweat rate in the selected skin surface area.

Compared with the prior art, the wearable sweat sensor for detecting the sweating amount and the sweating rate, the preparation method and the application thereof provided by the invention at least have the following beneficial effects:

(1) the invention firstly proposes to utilize a mechanical sensing mechanism to realize real-time continuous detection of the sweating amount and the sweating rate information.

(2) The wearable sweat sensor and the wearable sweat device can realize real-time monitoring of sweat information of a wide range of skin areas, acquire a real-time sweat amount change curve of sweat according to a resistance change value recorded by the strain sensor, and acquire a sweat rate of the sweat according to a slope of the real-time sweat amount change curve.

(3) The wearable sweat sensor and the wearable sweat sensor device can test and analyze the sweat rate and the sweat amount of different areas of a human body, and do important foundation for establishing a sweat database of the human body.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a cross-sectional structure of a wearable sweat sensor for sweat volume and sweat rate detection placed on the skin according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of a wearable sweat sensor array for sweat volume and sweat rate detection according to an embodiment of the present invention.

Reference numerals: 1-skin; 11-the skin surface; 12-peeling; 13-sweat; 14-sweat glands; 2-expansion block; 3-a strain sensing layer; 31 — a first insulating fixing layer; 32-a strain sensor; 33-a second insulating fixing layer; 34-a first opening; 35-a second opening; 4-an adhesive layer; 5-wearable sweat sensor.

Detailed Description

In view of the defects of the prior art, the inventor of the present invention has made extensive research and practice to propose the technical solution of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.

Embodiments of the present invention provide a wearable sweat sensor for sweat volume and sweat rate detection, comprising:

the sweat absorbing mechanism can generate deformation of different degrees when absorbing sweat of different volumes;

and the sensing mechanism is used for monitoring the deformation degree of the sweat absorbing mechanism after absorbing sweat and generating a corresponding sensing signal.

Further, the sweat absorbing mechanism comprises a sweat absorbing expansion block, the sweat absorbing expansion block can continuously absorb sweat secreted from the surface of the skin in real time and generate volume expansion, the volume expansion amount of the sweat absorbing expansion block is positively correlated with the volume of the sweat absorbed by the sweat absorbing expansion block, and the volume expansion speed is positively correlated with the volume of the sweat absorbed in unit time.

Further, the sensing mechanism comprises a strain sensor, and the sweat absorbing expansion block can drive the strain sensor to generate different degrees of deformation after absorbing sweat with different volumes, so that the strain sensor generates corresponding sensing signals;

the deformation quantity of the strain sensor is positively correlated with the volume expansion quantity of the sweat-absorbing expansion block, and the deformation rate is positively correlated with the volume expansion speed of the sweat-absorbing expansion block.

Further, the sweat absorbing expansion block is film-shaped.

Preferably, the thickness of the sweat-absorbing expansion block is 0.5-3 mm.

Further, the strain sensor adopts a strain sensitive film sensor.

Furthermore, sensing mechanism is strain sensing layer, strain sensor sets up in strain sensing layer and with sweat-absorbing expansion piece contact, sweat-absorbing expansion piece can support and push strain sensor when absorbing the sweat inflation.

Furthermore, the strain sensing layer comprises an insulating fixed layer, a window is formed in the insulating fixed layer, the strain sensor is fixedly arranged in the insulating fixed layer, a local area is exposed out of the window, and the sweat-absorbing expansion block is in contact with the strain sensor from the local area exposed out of the window.

When the sweat sensor is attached to the surface of skin for sweat detection, sweat secreted from the surface of the skin with a certain area at a window is continuously absorbed by the water-absorbing expansion block in real time, the water-absorbing expansion block expands in volume, the super-hydrophobic superelasticity low-modulus strain sensitive thin-film sensor is jacked upwards, a real-time sweat amount change curve of the sweat is obtained according to a resistance change value recorded by the strain sensitive thin-film sensor, and the sweat rate of the sweat is obtained according to the slope of the real-time sweat amount change curve.

Further, insulating fixed bed includes first insulating fixed bed and the insulating fixed bed of second that sets gradually along the direction of keeping away from skin, be equipped with first opening, second opening on first insulating fixed bed, the insulating fixed bed of second respectively, first opening and second opening cooperation form the window, strain sensor fixes to be set up between first insulating fixed bed and the insulating fixed bed of second.

Preferably, the first insulating fixing layer and the second insulating fixing layer are made of polydimethylsiloxane elastic films.

Preferably, the thickness of the first insulating fixed layer and the second insulating fixed layer is 0.1-3 mm, and the area is 1-4 cm²。

Further, the central axes of the first opening and the second opening are coincident.

Furthermore, the sweat absorbing expansion block is arranged in the first opening, and the diameter of the sweat absorbing expansion block is the same as that of the first opening.

Further, the thickness of the sweat-absorbing expansion block is the same as that of the first insulating fixing layer.

Further, the wearable sweat sensor also includes an adhesive layer coupled to the strain sensing layer for attaching the wearable sweat sensor to a skin surface.

Wherein the adhesive layer is provided with a third opening to expose the sweat-absorbent swelling block to the skin.

In one embodiment, the adhesive layer 4 comprises an adhesive film.

Preferably, the thickness of the adhesive film is 10 to 50 μm.

In one embodiment, the sweat-absorbent expandable mass comprises a porous membrane support loaded with a superabsorbent polymer or a porous membrane structure formed primarily of a superabsorbent polymer.

Preferably, the superabsorbent polymer comprises particles, powder, fibers, or the like of sodium polyacrylate.

In another embodiment, the material of the sweat-absorbent swelling block comprises a mixture of a superabsorbent polymer and a pH-responsive dye molecule.

Wherein the pH responsive dye molecule comprises a small organic molecule that produces a color change at different pH values of sweat.

Wherein the organic micromolecules comprise Congo red, methyl red, thymol blue, bromothymol blue, phenolphthalein and the like.

When the wearable sweat sensor is attached to the surface of the skin for sweat detection, the sweat amount, the sweat rate and the pH change of sweat can be acquired at the same time without mutual interference.

Furthermore, the strain sensitive thin film sensor comprises a super-hydrophobic superelasticity low-modulus substrate and conductive nano materials, wherein the conductive nano materials are distributed in the substrate or coated on the surface of the substrate.

In one embodiment, the material of the substrate comprises a combination of any one or more of a thermoplastic elastomer, a thermoplastic polyurethane, polydimethylsiloxane, and silicone.

In one embodiment, the conductive nanomaterial includes any one of a carbon nanotube, graphene, a silver nanowire, a metal nanowire, and a metal nanofilm.

Because the strain sensitive film sensor has super-hydrophobic or water-resistant property, a sensing signal generated by the sensor cannot be interfered by water or water vapor.

In one embodiment, the sweat absorbing mechanism and the sensing mechanism are both multiple and arranged in an array.

Embodiments of the present invention also provide an apparatus for detecting an amount of perspiration and a rate of perspiration, including:

at least one wearable sweat sensor as described above; and

and the sweat signal acquisition and processing device is connected with the wearable sweat sensor and is used for continuously acquiring and analyzing the sensing signal output by the wearable sweat sensor.

Further, the device also includes a sensor array comprising a plurality of wearable sweat sensors arranged in an array.

Further, multiple wearable sweat sensors share the same strain sensor.

Further, the plurality of wearable sweat sensors are arranged in a cascade.

With the wearable sweat sensor array, detection of sweat volume and sweat rate over a larger area of the skin surface can be achieved.

An embodiment of the present invention further provides a method for manufacturing the wearable sweat sensor for detecting sweat amount and sweat rate, including:

respectively preparing a first insulating fixed layer and a second insulating fixed layer, and respectively forming a first opening and a second opening on the first insulating fixed layer and the second insulating fixed layer;

manufacturing a strain sensor, and fixedly arranging the strain sensor between the first insulating fixed layer and the second insulating fixed layer to form a strain sensing layer;

manufacturing a sweat absorption expansion block, and connecting the sweat absorption expansion block with a strain sensing layer;

the adhesive layer is attached to the strain sensing layer and the sweat-absorbent swelling mass is exposed to the skin from a third opening provided on the adhesive layer.

Further, the preparation method specifically comprises the following steps:

dissolving a super-hydrophobic super-elastic low-modulus substrate material and a conductive nano material in an organic solvent in sequence according to a proportion to form a homogeneous solution, and preparing the homogeneous solution into a film with a certain thickness by a spraying or spin coating method to form a strain sensitive film sensor;

or dissolving the super-hydrophobic super-elastic low-modulus substrate material in an organic solvent to obtain a thermoplastic elastomer solution, preparing the thermoplastic elastomer solution into a super-hydrophobic super-elastic low-modulus film with a certain thickness by a spin coating or bubble blowing method, and preparing a strain sensitive film on the film by a spraying method of a dispersion liquid of a conductive nano material to form the strain sensitive film sensor.

In one embodiment, the concentration of the conductive nanomaterial dispersion liquid is 1-10 mg/mL.

In one embodiment, the thickness of the super-hydrophobic super-elastic low modulus thin film is 0.1 to 1 μm.

In one embodiment, the thickness of the strain sensitive film is 50 to 150 nm.

Further, the preparation method of the expansion block specifically comprises the following steps:

uniformly and dispersedly attaching a high water-absorption polymer material on a non-woven fabric film, and covering a layer of non-woven fabric film on the high water-absorption polymer material to form a film-shaped expansion block;

or, the high water absorption polymer material is prepared into the film-shaped expansion block by a dry mechanical reinforcing method or a hot melt adhesive bonding method.

The embodiment of the invention also provides a sweat amount and sweat rate detection method, which comprises the following steps:

applying the wearable sweat sensor to a selected skin surface area;

and continuously collecting and analyzing the sensing signals output by the wearable sweat sensor, so as to realize the detection of the sweat amount and the sweat rate in the selected skin surface area.

Example 1

The structure of a wearable sweat sensor for sweat amount and sweat rate detection provided by the present embodiment is shown in fig. 1, and includes: first insulating fixed layer 31 and the insulating fixed layer 32 that set gradually along the direction of keeping away from skin are equipped with first opening 34, second opening 35 on first insulating fixed layer 31, the insulating fixed layer 32 of second respectively, and first opening 34 and the cooperation of second opening 35 form the strain window, and strain sensor 32 is fixed to be set up between first insulating fixed layer 31 and the insulating fixed layer 32 of second, and sweat-absorbing expansion piece 2 sets up in first opening and contacts with strain sensor 32. The wearable sweat sensor also comprises an adhesive layer 4, wherein the adhesive layer 4 is attached to the surface of the skin, and a third opening is arranged on the adhesive layer, so that the sweat absorbing expansion block 2 is exposed to the skin.

A method of making the sensor comprises the steps of:

1) the first insulating fixed layer 31 and the second insulating fixed layer 33 are prepared from a polydimethylsiloxane elastic film, wherein the thickness of the first insulating fixed layer 31 and the second insulating fixed layer 33 is 0.1-3 mm, and the area of the first insulating fixed layer 31 and the second insulating fixed layer 33 is 1-4 cm²；

2) Respectively forming a first circular opening 34 and a second circular opening 35 on the first insulating fixed layer 31 and the second insulating fixed layer 33 by using a puncher, wherein the first circular opening 34 and the second circular opening 35 form a strain window, and the diameter of the strain window is 1-10 mm;

3) selecting a thermoplastic elastomer (TPE) as a substrate material, fully dissolving thermoplastic elastomer particles in a cyclohexane solvent, and preparing a thermoplastic elastomer solution with the mass percentage concentration of 10-30 wt% and the viscosity of 300-10000 MPa & s;

4) pouring 20-50 mL of prepared thermoplastic elastomer solution into a flat-bottom glass watch glass with the diameter of 5-10 cm, extracting 10-50 mL of air by using an injector, inserting a needle point into the bottom of the solution, slowly injecting the air into the solution to swell the solution to form a complete large bubble film, enabling one surface of a first insulating fixing layer 31 to be close to the top surface of the large bubble film and tightly attached to the large bubble film, enabling the large bubble film to be attached to the first insulating fixing layer 31, and forming a complete suspended super-hydrophobic super-elastic low-modulus film in a window area of the first insulating fixing layer 31, wherein the thickness of the film is 0.1-1 mu m and is controlled by the volume of large bubbles injected with the solution, the concentration and the viscosity of the thermoplastic elastomer solution;

5) preparing a conductive nano material dispersion liquid, preferably 1-10 mg/mL silver nanowire dispersion liquid, preparing a strain sensitive film material on the super-hydrophobic superelasticity low-modulus film by a spraying method, and forming a strain sensor, wherein the thickness of the formed silver nanowire network structure film is 50-150 nm;

6) attaching conductive cloth as electrode leads to two ends of the silver nanowire film, and leading the leads out of the first insulating fixed layer 31;

7) the surface of the first insulating fixing layer 31, on which the strain sensor 32 is formed, and the second insulating fixing layer 33 are bonded by a polydimethylsiloxane prepolymer solution and then baked in an oven at 80 ℃ for 1 hour until the materials are completely cured;

8) preparing a water-absorbing expansion block 2, cutting according to the size of the first opening 34, and then embedding the water-absorbing expansion block into the first opening 34;

9) the cut adhesive layer 4 is attached to the lower surface of the first insulating fixing layer 31 according to the size and position of the first opening 34, and the adhesive layer may be a double-sided tape having a thickness of 10 to 50 μm.

Example 2

The structure and the manufacturing method of the wearable sweat sensor for detecting sweat amount and sweat rate provided by this embodiment are substantially the same as those of embodiment 1, except that:

the preparation method of the sweat-absorbing expansion block 2 comprises the following steps:

uniformly and dispersedly attaching a high water-absorption polymer material on a non-woven fabric film, and covering a layer of non-woven fabric film on the high water-absorption polymer material to form a sweat-absorbing expansion block in a non-woven fabric film shape;

specifically, particles, powder or fibers of sodium polyacrylate are uniformly and dispersedly attached to a porous fiber non-woven fabric film carrier through a mesh screen, and then a layer of non-woven fabric film is covered on the surfaces of the dispersed particles, powder or fibers to form the sweat-absorbing expansion block with the thickness ranging from 0.5 mm to 3mm in a sandwich film shape.

Example 3

The structure and the manufacturing method of the wearable sweat sensor for detecting sweat amount and sweat rate provided by this embodiment are substantially the same as those of embodiment 2, except that:

the preparation method of the sweat-absorbing expansion block 2 comprises the following steps:

the high-water-absorption polymer materials such as sodium polyacrylate particles, powder or fibers are prepared into the thin-film-shaped sweat-absorption expansion block by a dry mechanical reinforcement or hot melt adhesive bonding method, and the thickness of the thin-film-shaped sweat-absorption expansion block is 0.5-3 mm.

Example 4

The structure of a wearable sweat sensor for sweat amount and sweat rate detection provided by the present embodiment is shown in fig. 2, and includes: a sensor array consisting of a plurality of wearable sweat sensors arranged in cascade, wherein the plurality of wearable sweat sensors share the same strain sensor 32.

A method of making the sensor similar to example 1, comprising:

designing a window array according to a structure of the wearable sweat sensor;

the strain sensing layer 3 is made and the corresponding number and size of the sweat-absorbent intumescent blocks 2 are made according to the size and number of the windows, which may be strain sensitive film sensors.

More specifically, the method of manufacturing the wearable sweat sensor comprises:

manufacturing a plurality of sweat absorbing expansion blocks 2;

preparing an array mold of the first insulating fixing layer 31 according to actual requirements, wherein the thickness of the mold is 1-5 cm, and the material of the mold can be plastic, polymer or metal material with higher modulus;

coating a first layer of epoxy resin on the surface of the frame surface of the mold by adopting a seal transfer printing method, and forming a first insulating fixed layer 31 after curing;

pressing the array mold of the first insulating fixing layer 31 on the prepared sweat-absorbing expansion block 2, and dividing the sweat-absorbing expansion block 2 into corresponding expansion block arrays;

preparing the strain sensor 32 by the corresponding method, and attaching the strain sensor 32 to the first layer of epoxy resin before the first layer of epoxy resin is uncured;

coating a second layer of epoxy resin on the first layer of epoxy resin by adopting a seal transfer printing method again, and forming a second insulating fixed layer 33 after curing;

the cut adhesive layer 4 is attached to the first insulating fixed layer 31 according to the size and position of the first opening 34.

Specifically, referring to fig. 1, when the wearable sweat sensor for detecting sweat amount and sweat rate provided by the embodiment of the invention is disposed on the skin, sweat 13 secreted by sweat glands 14 of the hypodermis 12 of the skin can be rapidly absorbed by the sweat absorbing expansion block 2. At this time, the sweat absorbing swelling block 2 expands in volume, and the expanded volume is positively correlated with the volume of the sweat to be absorbed, the volume expansion of the sweat absorbing swelling block 2 pushes up the strain sensor 32 to deform the strain sensor, the deformation amount of the strain sensor 32 is positively correlated with the volume of the sweat to be absorbed by the sweat absorbing swelling block 2, and the change rate of the deformation is positively correlated with the sweat release rate of the sweat to be absorbed by the sweat absorbing swelling block 2 per unit time. And acquiring a real-time sweat amount change curve of sweat according to the resistance change value recorded by the strain sensor 32, and acquiring the sweat rate of the sweat according to the slope of the real-time sweat amount change curve.

In the invention, sweat secreted on the surface of skin with a certain area is continuously and rapidly absorbed by the water absorption expansion block in real time, the volume of the water absorption expansion block is expanded, the change of the volume is recorded and converted into a resistance change curve by the strain sensing layer in real time, and the sweat amount and the sweat rate information of the sweat correspond to the resistance value and the change slope of the curve respectively.

In the invention, the sweat perspiration amount and perspiration rate information are detected by utilizing a mechanical sensing mechanism for the first time, and the wide-range perspiration rate and the wide-range skin area are monitored in real time; the wearable sweat sensor and the device can be used for testing and analyzing data of the sweat rate and the sweat amount of different areas of a human body, and an important basis is made for a human body sweat database.

As used herein, the term "include" and its variants mean open-ended terms in the sense of "including, but not limited to. The terms "based on," based on, "and the like mean" based at least in part on, "" based at least in part on. The terms "first," "second," and the like may refer to different or the same object.

It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention without departing from the spirit of the present invention and the protection scope of the claims.