A medical wearable flexible sensor assembly with an anti-fouling corrosion resistant coating
The medical wearable flexible sensor, with its multi-layer structure design, solves the problems of electrode failure caused by sweat corrosion and stress concentration, achieving the sensor's anti-fouling and corrosion resistance as well as signal stability, making it suitable for long-term health monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NORTHEASTERN UNIV CHINA
- Filing Date
- 2026-06-09
- Publication Date
- 2026-07-24
AI Technical Summary
Existing medical wearable flexible sensors are prone to electrode failure due to sweat corrosion and stress concentration during long-term use. Existing protection strategies lack multi-level collaborative protection, and improper sweat management leads to a decrease in signal acquisition accuracy.
It adopts a multi-layer structure design, including a flexible substrate, an encapsulation layer, an anti-fouling layer, and a skin contact layer. Through the combination of grooved embedded electrodes, arched structure, breathable micropores, and microfluidic sweat channels, a multi-layer protection system is formed to optimize stress management and sweat excretion.
It significantly improves the sensor's anti-fouling and corrosion resistance, extends its service life, ensures the stability and accuracy of signal acquisition, and is suitable for long-term contact with human skin.
Smart Images
Figure CN224552406U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of sensor technology, and in particular relates to a medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating. Background Technology
[0002] Medical wearable flexible sensors are typically attached to the surface of human skin to collect physiological signals such as electrocardiograms and sweat biochemical signals, and are widely used in the field of health monitoring. These sensors generally consist of a flexible substrate, sensing electrodes, and an encapsulation layer. In practical use, prolonged contact between the sensor and sweat, sebum, and external contaminants can easily lead to electrode coverage or corrosion, resulting in decreased signal acquisition accuracy. Especially when the sensor bends with the skin, the encapsulation layer is prone to stress concentration and cracking in the electrode area, allowing sweat to seep into the electrodes and cause failure.
[0003] To address the aforementioned issues, existing technologies primarily improve upon these aspects in the following ways: first, by employing superhydrophobic coatings to impart self-cleaning and anti-fouling properties to the sensor surface; second, by optimizing encapsulation materials and processes to enhance encapsulation density and prevent sweat penetration; and third, by incorporating microchannels or vents within the sensor to guide sweat excretion. However, these solutions still suffer from the following shortcomings: First, protection strategies are often limited to a single level, lacking a multi-layered collaborative protection system encompassing sweat source control, penetration path blocking, and encapsulation structure optimization. If the encapsulation is partially damaged, corrosive media will directly contact the electrodes. Second, existing encapsulation layers lack specialized structural stress management designs under dynamic bending conditions, making material optimization alone insufficient to prevent cracking of the encapsulation layer above the electrodes. Third, current sweat management focuses primarily on the sensor's outer surface, neglecting the issue of sweat accumulation in the skin contact layer due to its lack of breathability. The inability to expel water vapor in a timely manner exacerbates sweat generation, accelerating corrosion of the bottom electrodes. Utility Model Content
[0004] To address the shortcomings of existing technologies, this invention provides a medical wearable flexible sensor component with a dirt-resistant and corrosion-resistant coating. This component can work synergistically on multiple levels and has both dirt-resistant and corrosion-resistant properties, thus solving the problem of performance degradation caused by sweat erosion during long-term dynamic use.
[0005] A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating includes:
[0006] Flexible substrate;
[0007] Sensing electrodes are disposed on the flexible substrate;
[0008] An encapsulation layer covers the sensing electrode and is sealed to the flexible substrate;
[0009] An anti-fouling layer is disposed on the side of the encapsulation layer away from the flexible substrate;
[0010] A skin contact layer is disposed on the side of the flexible substrate away from the antifouling layer;
[0011] The area of the encapsulation layer corresponding to the sensing electrode has an arched structure that protrudes away from the flexible substrate.
[0012] The flexible substrate has a groove on the side surface near the encapsulation layer, and the sensing electrode is embedded in the groove, with the upper surface of the sensing electrode not higher than the upper surface of the flexible substrate.
[0013] The surface of the anti-fouling layer away from the encapsulation layer has a micro-uneven structure, which consists of regularly arranged micro-pits or randomly distributed nano-scale protrusions.
[0014] The surface of the antifouling layer has at least one micro-flow sweat-guiding groove, and the depth of the micro-flow sweat-guiding groove is greater than the height of the undulation of the micro-concave-convex structure.
[0015] The microfluidic sweat channel extends from the center area of the anti-fouling layer to the edge area.
[0016] The skin contact layer has breathable micropores that penetrate the skin contact layer along its thickness direction.
[0017] The flexible substrate has micro-bumps on the side of its surface closest to the skin contact layer. The micro-bumps are hemispherical or conical.
[0018] The arched structure is hollow inside.
[0019] The arched structure is filled with a low-elasticity modulus material.
[0020] The antifouling layer is a superhydrophobic coating, and the skin contact layer is a medical pressure-sensitive adhesive layer.
[0021] By employing the above technical solution, this utility model application has at least the following beneficial effects:
[0022] The medical wearable flexible sensor assembly with anti-fouling and corrosion-resistant coating provided by this utility model achieves significant anti-fouling and corrosion-resistant performance under long-term dynamic use conditions through the synergistic design of a multi-layer structure. Specifically:
[0023] 1. This utility model forms three lines of corrosion resistance, significantly improving its resistance to sweat corrosion:
[0024] This invention constructs a multi-level, systematic corrosion-resistant protection system through the following structural design:
[0025] The first line of defense involves embedding the sensing electrode within a groove in a flexible substrate, with the upper surface of the electrode not exceeding the upper surface of the flexible substrate. This structure physically surrounds the electrode with the sidewalls of the substrate, effectively extending the path of corrosive media such as sweat from the edges or cracks of the encapsulation layer to the electrode, thereby delaying the arrival time of the corrosive media.
[0026] The second line of defense: An arched structure is provided in the area of the encapsulation layer corresponding to the sensing electrode, protruding away from the flexible substrate. This arched structure preferentially deforms and absorbs bending stress when the sensor bends with the skin, avoiding stress concentration and cracks in the encapsulation layer directly above the electrode, thus ensuring the long-term integrity of the encapsulation layer.
[0027] The third line of defense: breathable micropores are formed on the skin contact layer, and micro-protrusions are set on the lower surface of the flexible substrate. The breathable micropores allow water vapor evaporated from the skin to be discharged in time, reducing the generation and accumulation of sweat at the bottom interface of the sensor; the micro-protrusions reduce the contact area with the skin, further improving air circulation and reducing the erosion of the bottom of the sensor by sweat from the source.
[0028] 2. This utility model combines surface anti-fouling and sweat-wicking functions, reducing the adhesion of pollutants:
[0029] The micro-unraveling structure on the surface of the anti-fouling layer gives it superhydrophobic properties, allowing liquids such as sweat to easily roll off and reducing contaminant adhesion. Simultaneously, microfluidic channels on the surface of the anti-fouling layer quickly guide accumulated sweat to the sensor edge, preventing sweat from remaining on the sensor surface for extended periods. This structure further reduces the risk of sweat contacting the encapsulation layer and electrodes from the outside of the sensor.
[0030] In summary, this invention systematically solves the technical problems of electrode corrosion and signal failure in existing medical wearable flexible sensors under dynamic and humid conditions through a multi-synergistic design that combines groove-embedded electrodes, arched structure encapsulation, breathable micropores for sweat wicking, and surface anti-fouling and sweat-wicking. It has significant corrosion resistance, bending fatigue resistance, and signal stability, making it suitable for long-term contact with human skin. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the layered structure of the medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to this utility model.
[0032] Figure 2 A cross-sectional schematic diagram of a medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating provided in Embodiment 1 of this utility model;
[0033] In the picture:
[0034] 1. Anti-fouling layer; 11. Microscopic uneven structure; 2. Encapsulation layer; 21. Arched structure; 3. Flexible substrate; 31. Micro-bumps; 32. Recessed space; 4. Skin contact layer; 5. Sensing electrode. Detailed Implementation
[0035] To better explain and facilitate understanding of this utility model, the technical solution and effects of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0036] Example 1
[0037] like Figures 1-2 As shown in the figure, this embodiment provides a medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating, which includes, from top to bottom, a dirt-resistant layer 1, an encapsulation layer 2, a flexible substrate 3, and a skin contact layer 4 along the thickness direction. The flexible substrate 3 integrates sensing electrodes 5.
[0038] The flexible substrate 3 is made of polydimethylsiloxane and is in the shape of a rectangular sheet with a thickness of 100μm to 300μm. Multiple grooves are formed on the upper surface of the flexible substrate 3, near the encapsulation layer 2, with a depth of 50μm to 150μm. The shape of the grooves matches the pattern of the sensing electrode 5 to be embedded. Multiple hemispherical micro-bumps 31 are evenly distributed on the lower surface of the flexible substrate 3, near the skin contact layer 4. The height of the micro-bumps 31 is 10μm to 30μm, used to reduce the contact area with the skin and improve local breathability.
[0039] Furthermore, the sensing electrode 5 is made of silver / silver chloride conductive paste, which is screen-printed into the grooves of the flexible substrate 3 to form a pattern of working electrode, counter electrode, and reference electrode. Even further, the upper surface of the sensing electrode 5 is slightly lower than the upper surface of the flexible substrate 3, with a height difference of 5μm to 15μm, thereby forming a tiny recessed space 32 above the grooves. This recessed space 32 can provide cushioning when the encapsulation layer 2 is under pressure, while also extending the lateral penetration path of corrosive media such as sweat.
[0040] The encapsulation layer 2 is made of polyurethane material with a thickness of 20μm to 50μm, covering the upper surface of the flexible substrate 3 and the sensing electrodes 5 embedded therein. Furthermore, the lower surface of the encapsulation layer 2 is directly bonded to the upper surface of the flexible substrate 3 after plasma activation treatment, forming a seamless sealed connection. On the encapsulation layer 2, corresponding to the area where each sensing electrode 5 is located, an arched structure 21 protruding away from the flexible substrate 3 is provided. In this embodiment, the arched structure 21 is a semi-circular protrusion with a height of 30μm to 80μm and a width approximately equal to the width of the groove below. The interior of the arched structure 21 is hollow, allowing it to deform preferentially and absorb bending stress when the sensor bends, thereby preventing cracks from forming in the encapsulation layer 2 directly above the electrodes.
[0041] The antifouling layer 1 is made of photocurable resin and has a thickness of 10μm to 30μm, and is disposed on the upper surface of the encapsulation layer 2. Furthermore, the surface of the antifouling layer 1 away from the encapsulation layer 2 has a micro-uneven structure 11. In this embodiment, the micro-uneven structure 11 consists of regularly arranged inverted pyramid-shaped micro-pits, with a side length of 2μm to 5μm and a depth of 1μm to 3μm. This micro-uneven structure 11 imparts superhydrophobic properties to the antifouling layer 1, causing liquids such as sweat to form spherical shapes on the surface and easily roll off, reducing the adhesion of contaminants.
[0042] Preferably, four microfluidic sweat-guiding grooves are further formed on the surface of the anti-fouling layer 1. These grooves extend radially from the central region of the anti-fouling layer 1 towards the four edges, with a groove width of 50μm~100μm and a groove depth of 8μm~15μm, greater than the height of the micro-protrusion structure 11. Simultaneously, the bottom and walls of the microfluidic sweat-guiding grooves also possess the micro-protrusion structure 11 on the side of the anti-fouling layer 1 away from the encapsulation layer 2. The microfluidic sweat-guiding grooves can quickly guide sweat accumulated on the surface of the anti-fouling layer 1 to the edge of the sensor, preventing long-term sweat retention.
[0043] The skin contact layer 4 is made of medical pressure-sensitive adhesive with a thickness of 30μm to 60μm and is disposed on the lower surface of the flexible substrate 3. Multiple breathable micropores, with a pore size of 20μm to 50μm, are formed on the skin contact layer 4, arranged in an array and extending through the layer along its thickness. These micropores allow water vapor evaporated from the skin to escape promptly, reducing the generation and accumulation of sweat at the sensor's bottom interface and mitigating the risk of sweat erosion of the sensor's bottom from the source.
[0044] The working principle of the medical wearable flexible sensor assembly with anti-fouling and corrosion-resistant coating provided in this embodiment is as follows:
[0045] The aforementioned sensor assembly achieves its anti-fouling and corrosion-resistant functions through the following three lines of defense. First line of defense: The sensing electrode 5 is embedded in a groove in the flexible substrate 3, and the electrode is physically surrounded by the sidewalls of the substrate, effectively extending the penetration path of corrosive media such as sweat. Second line of defense: The encapsulation layer 2 has an arched structure 21 corresponding to the electrode area. When the sensor bends with the skin, the arched structure 21 preferentially deforms to absorb stress, preventing cracks from forming in the encapsulation layer 2 above the electrode and ensuring the long-term integrity of the encapsulation layer 2. Third line of defense: The breathable micropores on the skin contact layer 4 promptly expel water vapor, reducing sweat generation; simultaneously, the micro-uneven structure 11 and microfluidic sweat-guiding grooves of the anti-fouling layer 1 quickly guide sweat away, further reducing the contact time and area between corrosive media and the sensor.
[0046] Example 2
[0047] The first difference between this embodiment and Embodiment 1 is that the micro-uneven structure 11 on the surface of the antifouling layer 1 in this embodiment consists of randomly distributed nanoscale nipple-like protrusions with a height of 100nm~500nm, mimicking the micro-structure of a lotus leaf surface, thus achieving a better superhydrophobic effect. The second difference is that, preferably, the arched structure 21 of the encapsulation layer 2 is filled with a low elastic modulus material, specifically silicone gel, with an elastic modulus less than 100kPa, to further enhance stress absorption capacity and provide structural stability to the arched structure 21, preventing the hollow structure from collapsing after repeated bending. The third difference is that the micro-protrusions 31 on the lower surface of the flexible substrate 3 are conical in shape, with a height of 20μm~50μm, further reducing the contact area with the skin and improving airflow. The remaining structure and working principle are the same as in Embodiment 1.
[0048] Example 3
[0049] This embodiment provides a method for fabricating the above-mentioned sensor component, including the following steps:
[0050] (1) A groove is formed on the upper surface of the polydimethylsiloxane substrate by molding or photolithography, and micro-bumps 31 are formed on the lower surface of the substrate;
[0051] (2) Silver / silver chloride conductive paste is screen printed in the groove, and the sensing electrode 5 is formed by curing at 80°C for 30 minutes. The upper surface of the sensing electrode 5 is controlled to be 5μm~15μm lower than the upper surface of the substrate.
[0052] (3) Spin-coating polyurethane prepolymer onto the upper surface of the substrate and curing it locally with ultraviolet light through a mask to form an encapsulation layer 2 with an arched structure 21; the interior of the arched structure 21 is hollow or filled with low elastic modulus silicone gel by injection.
[0053] (4) A photocurable acrylic resin is spin-coated on the upper surface of the encapsulation layer 2, and a micro-uneven structure 11 is formed by nanoimprinting technology. A radial microfluidic sweat channel is formed by laser etching, and finally, an anti-fouling layer 1 is formed by UV curing.
[0054] (5) Apply medical pressure-sensitive adhesive to the lower surface of the substrate, press and cure it through a mold with a microporous array to form a skin contact layer 4 with breathable micropores.
[0055] Example 4
[0056] The difference between this embodiment and Embodiment 1 is that the flexible substrate 3 does not have micro-protrusions 31 on the surface near the skin contact layer 4, but remains flat overall, making it suitable for scenarios requiring high adhesive strength. Simultaneously, the density of breathable micropores on the skin contact layer 4 is increased to 200-400 per square centimeter, and the pore size is reduced to 10μm-20μm, to maintain sufficient breathability without reducing adhesive strength.
Claims
1. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating, characterized in that, include: Flexible substrate; Sensing electrodes are disposed on the flexible substrate; An encapsulation layer covers the sensing electrode and is sealed to the flexible substrate; An anti-fouling layer is disposed on the side of the encapsulation layer away from the flexible substrate; A skin contact layer is disposed on the side of the flexible substrate away from the antifouling layer; The area of the encapsulation layer corresponding to the sensing electrode has an arched structure that protrudes away from the flexible substrate.
2. The medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1, characterized in that: The flexible substrate has a groove on the side surface near the encapsulation layer, and the sensing electrode is embedded in the groove, with the upper surface of the sensing electrode not higher than the upper surface of the flexible substrate.
3. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1 or 2, characterized in that: The surface of the anti-fouling layer away from the encapsulation layer has a micro-uneven structure, which consists of regularly arranged micro-pits or randomly distributed nano-scale protrusions.
4. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 3, characterized in that: The surface of the antifouling layer has at least one micro-flow sweat-guiding groove, and the depth of the micro-flow sweat-guiding groove is greater than the height of the undulation of the micro-concave-convex structure.
5. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 4, characterized in that: The microfluidic sweat channel extends from the center area of the anti-fouling layer to the edge area.
6. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1, characterized in that: The skin contact layer has breathable micropores that penetrate the skin contact layer along its thickness direction.
7. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1, characterized in that: The flexible substrate has micro-bumps on the side of its surface closest to the skin contact layer. The micro-bumps are hemispherical or conical.
8. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1, characterized in that: The arched structure is hollow inside.
9. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1, characterized in that: The arched structure is filled with a low-elasticity modulus material.
10. A medical wearable flexible sensor assembly with a dirt-resistant and corrosion-resistant coating according to claim 1, characterized in that: The antifouling layer is a superhydrophobic coating, and the skin contact layer is a medical pressure-sensitive adhesive layer.