CN108975266B - graphene-PDMS flexible substrate electrocardio dry electrode based on needle tip array structure and preparation method thereof - Google Patents
graphene-PDMS flexible substrate electrocardio dry electrode based on needle tip array structure and preparation method thereof Download PDFInfo
- Publication number
- CN108975266B CN108975266B CN201810784683.2A CN201810784683A CN108975266B CN 108975266 B CN108975266 B CN 108975266B CN 201810784683 A CN201810784683 A CN 201810784683A CN 108975266 B CN108975266 B CN 108975266B
- Authority
- CN
- China
- Prior art keywords
- pdms
- graphene
- array structure
- layer
- curing agent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/24—Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
- A61B5/25—Bioelectric electrodes therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/02—Details of sensors specially adapted for in-vivo measurements
- A61B2562/0209—Special features of electrodes classified in A61B5/24, A61B5/25, A61B5/283, A61B5/291, A61B5/296, A61B5/053
- A61B2562/0215—Silver or silver chloride containing
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
- A61B2562/12—Manufacturing methods specially adapted for producing sensors for in-vivo measurements
- A61B2562/125—Manufacturing methods specially adapted for producing sensors for in-vivo measurements characterised by the manufacture of electrodes
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Surgery (AREA)
- General Health & Medical Sciences (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Physics & Mathematics (AREA)
- Animal Behavior & Ethology (AREA)
- Biomedical Technology (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Computer Hardware Design (AREA)
- Pathology (AREA)
- Biophysics (AREA)
- Electrotherapy Devices (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
Abstract
The invention relates to a graphene-PDMS flexible substrate electrocardio dry electrode based on a needle point array structure and a preparation method thereof, and the graphene-PDMS flexible electrocardio dry electrode comprises a graphene-PDMS flexible conductive substrate with a needle point array structure design on the top surface, wherein a parylene film is deposited on the needle point array structure, a metal seed layer is sputtered on the parylene film, and a metal layer is sputtered on the metal seed layer; the bottom surface of the graphene-PDMS flexible conductive substrate is coated with a conductive silver glue layer. The method has the advantages of simple process steps and low cost, and is favorable for batch production through the manufacture of the die. The materials used in the invention, such as conductive silver adhesive, PDMS, graphene, parylene film and sputtered metal titanium and gold, have good biocompatibility, can effectively inhibit bacteria and reduce skin irritation. The needle tip array structure designed by the invention has larger contact area, can directly contact with the skin and can pass through the stratum corneum, and can effectively reduce the contact impedance of the skin and the electrode, thereby obtaining stable electrocardiosignals.
Description
Technical Field
The invention relates to the field of medical instruments prepared by an MEMS (micro-electromechanical systems) technology, in particular to a graphene-PDMS (polydimethylsiloxane) flexible substrate electrocardio dry electrode based on a needle tip array structure and a preparation method thereof.
Background
At present, the polymer becomes a processing material widely applied in the technical field of MEMS. According to the characteristics of good biocompatibility, flexibility, ductility and the like, the material has very ideal application prospect in the field of novel biological micro-electromechanical sensors. The types of polymers are generally classified into elastomers, conductive polymers, hydrogels, epoxies, etc. according to the characteristics of the material.
Polydimethylsiloxane (PDMS) is a high molecular organic silicon polymer, and is widely applied to aspects such as biological PDMS stamps, microfluidic devices, biological touch sensors and the like prepared from flexible packaging materials due to the advantages of low cost, good chemical inertness, simple processing technology, special material characteristics and the like.
Graphene is a carbonaceous material having a two-dimensional honeycomb lattice structure, and is a thin film material having a thickness of only one carbon atom layer. Meanwhile, the graphene is an excellent antibacterial material. Due to the excellent properties of excellent conductivity, super-large specific surface area, high Young modulus, high carrier mobility, ferromagnetism and the like, the graphene has a wide application prospect in the fields of nano electronic devices, batteries, super capacitors, hydrogen storage materials, ultra-sensitive sensors, biomedical sensors and the like.
Parylene (Parylene) is a chemically inert material and is also a material used for conformal coating and polymer insulation. According to the literature report, it is often used as medical coating, insulating layer of implanted nerve electrode and dielectric between layers. Parylene (Parylene) films have good biocompatibility, low toxicity and flexibility, and thus are widely used in the biomedical field.
A hollow pinpoint neural electrode Array for retina repair is reported by Renxin Wang et al in the contamination and Characterization of a Parylene-based 3D Microelectrode Array for Use in Retinal repair, Journal of microelectrochemical systems, vol.19, pp. 367-374, 2010, a pinpoint electrode Array silicon die is prepared by deep silicon etching and wet etching processes, the topography transfer on a Parylene substrate is completed by conformal deposition characteristics of a Parylene film, and finally the hollow pinpoint neural electrode Array is obtained by tearing off the silicon die.
Therefore, aiming at the problems that the fitness of the conventional wet electrocardio electrode is poor, the quality of a signal is poor, the contact impedance with the skin is increased, the skin is irritated, the flexibility of a dry electrode is poor, the conductivity is poor, the fitness is poor and the like caused by the gradual drying of the conductive paste coated on the wet electrocardio electrode, the design is improved from the aspects of structure and process, and the graphene-PDMS flexible substrate dry electrocardio electrode array based on the needle point structure and the preparation method thereof are provided.
Disclosure of Invention
The invention aims to provide a graphene-PDMS flexible substrate electrocardio dry electrode based on a pinpoint array structure and a preparation method thereof, aiming at the defects of the existing electrocardio dry electrode and wet electrode. The invention has the advantages of simple process steps, high yield, good biocompatibility, small contact impedance, stable signal quality and the like.
The invention is realized by the following technical scheme:
a graphene-PDMS flexible substrate electrocardio dry electrode based on a needle tip array structure comprises a graphene-PDMS flexible conductive substrate, wherein the top surface of the graphene-PDMS flexible conductive substrate is designed into a needle tip array structure, a parylene film is deposited on the needle tip array structure, a metal seed layer is sputtered on the parylene film, and a metal layer is sputtered on the metal seed layer; the bottom surface of the graphene-PDMS flexible conductive substrate is coated with a conductive silver glue layer. Wherein, the conductive silver colloid layer is used as a metal lead layer; the parylene film is used as an adhesion layer between the graphene-PDMS flexible conductive substrate and the metal seed layer.
As the preferred technical scheme, the length and width of the electrocardio dry electrode are 1 multiplied by 1 cm; the thickness of the graphene-PDMS flexible substrate is 300-500 μm; the distance between adjacent needle points in the needle point array structure is 160-240 mu m; the diameter of the bottom circle of each needle point is 70 mu m, the diameter of the top circle is 5 mu m, and the height is 90 mu m; the thickness of the parylene film is 500 nm; the thickness of the metal seed layer is 150nm, the material of the metal seed layer is titanium, and the titanium is selected to enhance the adhesion between the metal layer and the parylene film; the thickness of the metal layer is 20nm, the metal layer is made of gold, and the metal gold is selected because the metal gold has good biocompatibility and does not harm human bodies; the thickness of the conductive silver paste layer was 500 μm.
The invention improves the stability of electrocardiosignals from the angle of reducing contact impedance as much as possible, and specifically comprises the following steps: in the aspect of structure, the graphene-PDMS flexible conductive substrate designed with the needle tip array structure is adopted, so that the skin-electrode contact impedance can be reduced through the stratum corneum, a stable electrocardiosignal is obtained, the same effect as a wet electrode is achieved, and the graphene-PDMS flexible conductive substrate has good flexibility and conductivity. In terms of contact area, the electrocardio dry electrode designed by the invention preferably has the size of 1cm multiplied by 1cm (namely, the length and the width are respectively 1 cm), and the distance between adjacent needle points is 160-240 mu m, so that the effective contact area is increased to reduce the contact impedance of the skin and the electrode.
The invention also provides a preparation method of the graphene-PDMS flexible substrate electrocardio dry electrode based on the needlepoint array structure, which comprises the following steps:
1) cleaning a silicon wafer, and coating a Hexamethyldisilazane (HMDS) adhesion layer;
2) uniformly spin-coating a positive photoresist, developing and hardening;
3) forming a silicon column array structure by adopting a deep silicon etching technology, and removing the photoresist by a plasma surface treatment method after finishing the forming;
4) corroding the silicon column array structure into a silicon needle tip array structure by adopting a wet etching technology;
5) depositing a layer of parylene film on the silicon needle tip array structure of the silicon wafer to complete the manufacturing of the silicon die;
6) mixing PDMS and a curing agent, stirring uniformly, extracting bubbles, pouring on a silicon mold, heating for curing, and uncovering the film;
7) depositing a layer of parylene film on the uncovered film to finish the manufacture of the PDMS groove needle point array structure mold;
8) mixing the graphene aqueous dispersion liquid subjected to ultrasonic treatment with PDMS, stirring uniformly by magnetic force, and finally evaporating the volatile solvent at a certain temperature;
9) adding a curing agent into the mixture prepared in the step 8), uniformly stirring and extracting bubbles in the mixture;
10) pouring the mixture prepared in the step 9) on a PDMS groove needle point array structure mould, standing for a period of time, heating for curing, and then uncovering the film to complete the manufacture of the graphene-PDMS flexible conductive substrate with the needle point array structure;
11) depositing a layer of parylene film on a needle point array structure of a graphene-PDMS flexible conductive substrate, and then carrying out plasma surface treatment;
12) carrying out magnetron sputtering on a metal seed layer on the parylene film, and carrying out magnetron sputtering on a metal layer on the metal seed layer;
13) and coating a conductive silver adhesive layer on the back of the graphene-PDMS flexible conductive substrate, and finally finishing the manufacture of the electrocardio dry electrode array of the graphene-PDMS flexible substrate based on the pinpoint structure.
As a preferable technical scheme, in the step 6), the mass ratio of the PDMS to the curing agent is 5:1, 7.5:1 or 10:1, and the heating curing mode is as follows: gradually raising the temperature according to the temperature of 30-40-50-60-70 ℃, wherein the temperature lasts for 5min at the temperature of 30 ℃, 40 ℃, 50 ℃ and 60 ℃, and the mass ratio of the PDMS to the curing agent is 5:1 for 1.5h, the mass ratio of the PDMS to the curing agent is 7.5:1 for 2h and the mass ratio of the PDMS to the curing agent is 10:1 for 2.5h at the temperature of 70 ℃.
Preferably, in the step 8), the concentration of the graphene aqueous dispersion is 2mg/ml, the mass ratio of the graphene aqueous dispersion to the PDMS is 1: 5-1: 20, the temperature of the evaporation treatment is 70 ℃, and the holding time is 1 h.
As a preferable technical scheme, in the step 9), when the curing agent is added into the mixture, the curing agent is added according to the mass ratio of the PDMS to the curing agent of 5:1, 7.5:1 or 10: 1.
As a preferable technical solution, in the step 10), the temperature-raising curing method is as follows: gradually raising the temperature according to the temperature of 30-40-50-60-70 ℃, wherein the temperature lasts for 5min at the temperature of 30 ℃, 40 ℃, 50 ℃ and 60 ℃, respectively, the mixture with the mass ratio of PDMS to curing agent of 5:1 lasts for 1.5h at the temperature of 70 ℃, the mixture with the mass ratio of PDMS to curing agent of 7.5:1 lasts for 2h, and the mixture with the mass ratio of PDMS to curing agent of 10:1 lasts for 2.5 h.
As a preferable technical scheme, in the step 5), the thickness of the parylene film deposited for the first time is 500nm, and the parylene film is used for demoulding the silicon needle tip array structure and the PDMS groove needle tip array structure mould.
As a preferable technical scheme, in the step 7), the thickness of the parylene film deposited for the second time is 500nm, and the parylene film is used for demoulding the PDMS groove needle tip array structure mold and the graphene-PDMS flexible conductive substrate.
As a preferable technical scheme, in the step 11), the thickness of the parylene film deposited for the third time is 500nm, and the parylene film is used as an adhesion layer between the graphene-PDMS flexible conductive substrate and the magnetron sputtering metal seed layer to prevent the metal from wrinkling on the PDMS.
As a preferable technical solution, in the step 13), the thickness of the conductive silver paste layer coated on the back surface of the graphene-PDMS flexible conductive substrate is 500 μm.
The invention has the following beneficial effects:
1) the method has the advantages of simple process steps and low cost, and is favorable for batch production through the manufacture of the die.
2) The materials used in the invention, such as conductive silver adhesive, PDMS, graphene, parylene film and sputtered metal titanium and gold, have good biocompatibility, can effectively inhibit bacteria and reduce skin irritation.
3) The contact impedance is an important parameter for the microelectrode array, so the needle tip array structure designed by the invention has larger contact area, can pass through the stratum corneum by directly contacting with the skin, can effectively reduce the contact impedance of the skin and the electrode, and further obtains stable electrocardiosignals.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.
Fig. 1 is a schematic structural diagram of a graphene-PDMS flexible substrate electrocardio dry electrode based on a pinpoint array structure.
FIG. 2 is a process flow diagram of a preparation method of the graphene-PDMS flexible substrate electrocardio dry electrode based on the needlepoint array structure.
Fig. 3 is a flow chart of the preparation of the graphene-PDMS mixture according to the preparation method of the present invention.
In the figure: the device comprises a 1-graphene-PDMS flexible conductive substrate, a 2-needle point array structure, a 3-parylene film, a 4-metal seed layer, a 5-metal layer, a 6-conductive silver glue layer, a 7-silicon chip, an 8-photoresist and a 9-PDMS.
Detailed Description
In order that those skilled in the art will better understand the present invention, a more complete and complete description of the present invention is provided below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
As shown in fig. 1, a graphene-PDMS flexible substrate electrocardio dry electrode based on a needle tip array structure comprises a graphene-PDMS flexible conductive substrate 1, wherein the top surface of the graphene-PDMS flexible conductive substrate 1 is designed into a needle tip array structure 2, a parylene film 3 is deposited on the needle tip array structure 2, a metal seed layer 4 is sputtered on the parylene film 3, and a metal layer 5 is sputtered on the metal seed layer 4; the bottom surface of the graphene-PDMS flexible conductive substrate 1 is coated with a conductive silver glue layer 6. Wherein, the length and width of the electrocardio dry electrode are 1 multiplied by 1 cm; the thickness of the graphene-PDMS flexible substrate 1 is 300-500 μm; the distance between adjacent needle points in the needle point array structure 2 is 160-240 mu m; the diameter of the bottom circle of each needle point is 70 mu m, the diameter of the top circle is 5 mu m, and the height is 90 mu m; the thickness of the parylene film 3 is 500 nm; the thickness of the metal seed layer 4 is 150nm and the material is titanium; the thickness of the metal layer 5 is 20nm and the material is gold; the thickness of the conductive silver paste layer 6 was 500 μm.
The preparation method of the graphene-PDMS flexible substrate electrocardio dry electrode based on the needlepoint array structure comprises the following steps:
1) cleaning a silicon wafer, and coating a hexamethyldisilazane adhesion layer;
2) uniformly spin-coating a positive photoresist, developing and hardening;
3) forming a silicon column array structure by adopting a deep silicon etching technology, and removing the photoresist by a plasma surface treatment method after finishing the forming;
4) corroding the silicon column array structure into a silicon needle tip array structure by adopting a wet etching technology;
5) depositing a layer of parylene film on the silicon needle tip array structure of the silicon wafer to complete the manufacturing of the silicon die;
6) mixing PDMS and a curing agent, stirring uniformly, extracting bubbles, pouring on a silicon mold, heating for curing, and uncovering the film;
7) depositing a layer of parylene film on the uncovered film to finish the manufacture of the PDMS groove needle point array structure mold;
8) mixing the graphene aqueous dispersion liquid subjected to ultrasonic treatment with PDMS, stirring uniformly by magnetic force, and finally evaporating the volatile solvent at a certain temperature;
9) adding a curing agent into the mixture prepared in the step 8), uniformly stirring and extracting bubbles in the mixture;
10) pouring the mixture prepared in the step 9) on a PDMS groove needle point array structure mould, standing for a period of time, heating for curing, and then uncovering the film to complete the manufacture of the graphene-PDMS flexible conductive substrate with the needle point array structure;
11) depositing a layer of parylene film on a needle point array structure of a graphene-PDMS flexible conductive substrate, and then carrying out plasma surface treatment;
12) carrying out magnetron sputtering on a metal seed layer on the parylene film, and carrying out magnetron sputtering on a metal layer on the metal seed layer;
13) and coating a conductive silver adhesive layer on the back of the graphene-PDMS flexible conductive substrate, and finally finishing the manufacture of the electrocardio dry electrode array of the graphene-PDMS flexible substrate based on the pinpoint structure.
In the specific implementation, in the step 6), the mass ratio of the PDMS to the curing agent is 5:1, 7.5:1 or 10:1, and the heating and curing mode is as follows: gradually raising the temperature according to the temperature of 30-40-50-60-70 ℃, wherein the temperature lasts for 5min at the temperature of 30 ℃, 40 ℃, 50 ℃ and 60 ℃, and the mass ratio of the PDMS to the curing agent is 5:1 for 1.5h, the mass ratio of the PDMS to the curing agent is 7.5:1 for 2h and the mass ratio of the PDMS to the curing agent is 10:1 for 2.5h at the temperature of 70 ℃.
Specifically, in the step 8), the concentration of the graphene aqueous dispersion liquid is 2mg/ml, the mass ratio of the graphene aqueous dispersion liquid to the PDMS is 1: 5-1: 20, the temperature of the evaporation treatment is 70 ℃, and the holding time is 1 h.
In the specific implementation, in the step 9), when the curing agent is added into the mixture, the curing agent is added according to the mass ratio of the PDMS to the curing agent of 5:1, 7.5:1 or 10: 1.
In the specific implementation, in the step 10), the heating and curing mode is as follows: gradually raising the temperature according to the temperature of 30-40-50-60-70 ℃, wherein the temperature lasts for 5min at the temperature of 30 ℃, 40 ℃, 50 ℃ and 60 ℃, respectively, the mixture with the mass ratio of PDMS to curing agent of 5:1 lasts for 1.5h at the temperature of 70 ℃, the mixture with the mass ratio of PDMS to curing agent of 7.5:1 lasts for 2h, and the mixture with the mass ratio of PDMS to curing agent of 10:1 lasts for 2.5 h.
The preparation process of the present invention is further illustrated by the following specific preparation examples:
as in fig. 2 a, a photoresist is spin coated. Firstly, putting a 500-micron silicon wafer into two solutions of acetone and absolute ethyl alcohol in sequence, ultrasonically cleaning for 5min, and completely drying the silicon wafer by using a nitrogen gun after the ultrasonic cleaning is finished so as to ensure that the surface of the wafer is clean and dry; then placing the silicon wafer in a vacuum oven to be baked for 20min at the temperature of about 130 ℃ so as to coat a Hexamethyldisilazane (HMDS) adhesion layer, wherein the purpose is to increase the adhesion force between the photoresist and the silicon wafer and prevent the photoresist from being permeated by a developing solution in the subsequent developing process to avoid the phenomenon of photoresist stripping and bleaching; after photoetching, the thickness of deep silicon etching is larger, more photoresist is consumed, so that the uniform spin-coating positive photoresist is AZ4620, the photoresist homogenizing speed is 500r/min at a low speed for 10s and 4000r/min at a high speed for 30s, the thickness of the obtained photoresist is 6.5 mu m, organic solvent in the photoresist needs to be evaporated, and the pre-baking treatment is carried out after the photoresist is spin-coated, wherein the temperature is set to be 100 ℃, and the temperature is kept for 1.5 min.
E.g., b in fig. 2, photolithography. Using a contact lithography machine, the exposure dose was 200mJ/cm2(ii) a The developing solution corresponds to AZ400K series, the proportion of the developing solution to water is 1:3 or 1:4, and the developing time is 30-60 s; to improve photolithographyThe resist has the capability of resisting etching or corrosion by taking the photoresist as a mask, the photoresist and a silicon wafer can be more firmly adhered by hardening treatment after the photoresist is developed, and the hardening temperature is set at 120 ℃ for 5min because the thickness of the photoresist is thicker.
As shown at c in fig. 2, a deep silicon etch. Using a deep silicon etcher, the chamber pressure was set to 40mTorr, the height of the silicon pillar array was measured to be about 10 μm when the number of etching cycles was set to 10loop, and then set to 20loop, 30loop and 40loop, and the height of the silicon pillar array was measured to be about 100 μm after the etching was completed.
The photoresist is removed, as shown at d in fig. 2. Using a plasma degumming machine, setting the power to be 300W and setting the gas to be O2The gas flow rate was set at 3L/min for 20 min.
E in fig. 2, wet etching. Adopts HNA wet etching technology, which is obtained by uniformly mixing hydrofluoric acid, nitric acid and glacial acetic acid, and the proportion and the concentration are as follows: and preparing 240ml of solution by HF (40%), HNO3 (65%), HAC (100%) =1:3:8, fully stirring, and etching for 150min, wherein the diameter of the bottom circle, the diameter of the top circle and the height of the silicon tip structure are respectively 70 μm, 5 μm and 90 μm, and the diameter of the top circle and the height of the silicon tip structure are measured after the etching is finished. And (2) depositing a layer of Parylene (Parylene) film on the prepared needle point array structure as a film turning pretreatment mode for pattern transfer before pouring the PDMS, setting the deposition rate to be 500nm/hr, setting the deposition temperature to be 22 ℃ and the time to last for 1h by using a Parylene vacuum vapor deposition instrument, and setting the thickness of the first deposited film to be 500nm to finish the manufacturing of the silicon needle point mold.
PDMS was cast as in fig. 2, f. Adding a curing agent into PDMS, mixing and stirring uniformly, wherein the mass ratio of PDMS to the curing agent can be selected from 5:1, 7.5:1 or 10:1, pumping out air bubbles at normal temperature in a vacuum drying oven, then pouring the air bubbles on a silicon substrate on which a Parylene film is deposited, placing the silicon substrate on a horizontal drying table, standing for 3h at normal temperature to enable PDMS to reach uniform thickness on the silicon substrate, slowly heating and curing to enable residual solvent to volatilize, wherein the heating mode is a step-type heating mode and comprises five temperature steps of 30 ℃, 40 ℃, 50 ℃, 60 ℃ and 70 ℃, the first four temperature steps are respectively continued for 5min at 30 ℃, 40 ℃, 50 ℃ and 60 ℃, and the fifth temperature step is kept for 1.5h with PDMS in the ratio of 5:1 at 70 ℃, 2h with PDMS in the ratio of 7.5:1 in the ratio of curing agent and 2.5h with PDMS in the ratio of 10:1 in the ratio of curing agent.
As in g of fig. 2, PDMS groove tip mold. And after curing, slowly tearing off the cured film from the edge of the silicon substrate, and then depositing a layer of Parylene film on the surface of the PDMS needle point groove as film turning treatment for secondary pattern transfer, wherein the thickness of the deposited film for the second time is 500nm, thus finishing the complete manufacture of the PDMS groove needle point mold.
The graphene-PDMS mixture was cast as h in fig. 2. Firstly, preparing a graphene-PDMS mixture, wherein a specific preparation process flow is shown in fig. 3: 1) the conductive mixture doped in PDMS is a single-layer graphene aqueous dispersion liquid, and the concentration of the conductive mixture is 2 mg/ml; since the graphene dispersion liquid is precipitated or agglomerated at the bottom after being placed for a long time, before the graphene dispersion liquid is added into PDMS, the graphene dispersion liquid needs to be subjected to ultrasonic treatment for 15-30 min to obtain a uniform dispersion liquid; 2) Pouring the graphene dispersion liquid into PDMS after ultrasonic treatment, then placing on a magnetic stirrer, and stirring for 2h at normal temperature; the mass ratio of the graphene dispersion liquid to the PDMS is 1: 5-1: 20, and the smaller the ratio, the better the conductivity is; 3) putting the stirred graphene-PDMS mixture into a vacuum oven, keeping the temperature of the vacuum oven at 70 ℃ for 1h to evaporate residual solvent; 4) and then adding a curing agent in proportion, fully and uniformly stirring, and then placing in a vacuum drying oven to extract air bubbles at normal temperature, wherein the mass ratio of the PDMS to the curing agent can be 5:1, 7.5:1 or 10: 1. Then, pouring the prepared graphene-PDMS mixture on a PDMS groove needle point mold for depositing a Parylene film, placing the PDMS groove needle point mold on a leveling drying table, standing the PDMS mixture for 3 hours at normal temperature to enable the graphene-PDMS mixture to reach uniform thickness on the PDMS groove needle point mold, and then slowly heating and curing the PDMS mixture to enable the residual solvent to volatilize; the heating mode is staged heating, and comprises five temperature stages of 30 ℃, 40 ℃, 50 ℃, 60 ℃ and 70 ℃, the first four temperature stages are respectively continued for 5min at 30 ℃, 40 ℃, 50 ℃ and 60 ℃, and when the fifth temperature stage is at 70 ℃, the graphene-PDMS mixture with the ratio of PDMS to curing agent of 5:1 is kept for 1.5h, the graphene-PDMS mixture with the ratio of PDMS to curing agent of 7.5:1 is kept for 2h, and the graphene-PDMS mixture with the ratio of PDMS to curing agent of 10:1 is kept for 2.5 h.
As in fig. 2, i, a graphene-PDMS flexible substrate. After curing, slowly tearing off the edge of the PDMS groove needle point mold to obtain a graphene-PDMS flexible substrate, and then depositing a 500nm Parylene film on the surface of the graphene-PDMS flexible substrate as an adhesion layer between the metal layer and the flexible substrate, wherein the thickness of the deposited film for the third time is 500 nm; and because the Parylene film has insulation property, the surface treatment is carried out by a plasma degumming machine to ensure that the Parylene film is conductive, the power is set to be 500W, and the gas is set to be O2And setting the gas flow to be 3L/min, and lasting for 5min to finish the whole manufacture of the graphene-PDMS flexible substrate.
Metal was magnetron sputtered and coated with conductive silver paste as in j in fig. 2. Using a magnetron sputtering coating machine, setting the rotating speed of a turntable to be 10-30 r/min, firstly sputtering 150nm of metal seed layer titanium on a graphene-PDMS flexible substrate on which a Parylene film is deposited to enhance the adhesion of gold and the Parylene film layer, and then sputtering 20nm of metal layer gold on the metal seed layer; and coating a layer of conductive silver adhesive with the thickness of 500 mu m on the back of the flexible substrate, and curing at normal temperature for about 5 hours to complete the whole manufacture of the graphene-PDMS flexible substrate electrocardio dry electrode based on the pinpoint array structure.
The size of the dry electrocardio electrode prepared by the invention is preferably 1cm multiplied by 1cm (namely the length and the width are respectively 1 cm), the distance between adjacent needle points is 160-240 mu m, and preferably 160 mu m, 180 mu m, 200 mu m and 240 mu m; when the distance between adjacent needle points is 160 mu m, the array element of the electrocardio dry electrode is 50 multiplied by 50, namely, the electrocardio dry electrode has 50 multiplied by 50 needle points; when the distance between adjacent needle points is 180 mu m, the array element of the electrocardio dry electrode is 45 multiplied by 45, namely, the electrocardio dry electrode has 45 multiplied by 45 needle points; when the distance between adjacent needle points is 200 mu m, the array element of the electrocardio dry electrode is 40 multiplied by 40, namely, the electrocardio dry electrode has 40 multiplied by 40 needle points; when the distance between adjacent needle points is 240 μm, the array elements of the electrocardio-dry electrode are 35 × 35, that is, 35 × 35 needle points are totally arranged on the electrocardio-dry electrode.
The technical solutions in the embodiments of the present invention are clearly and completely described above, and the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Claims (2)
1. The utility model provides a graphite alkene-PDMS flexible substrate electrocardio dry electrode based on needle point array structure which characterized in that: the graphene-PDMS flexible conductive substrate comprises a graphene-PDMS flexible conductive substrate (1), wherein the top surface of the graphene-PDMS flexible conductive substrate (1) is designed into a needle point array structure (2), a parylene film (3) is deposited on the needle point array structure (2), a metal seed layer (4) is sputtered on the parylene film (3), a metal layer (5) is sputtered on the metal seed layer (4), and a conductive silver glue layer (6) is coated on the bottom surface of the graphene-PDMS flexible conductive substrate (1);
the preparation method of the graphene-PDMS flexible substrate electrocardio dry electrode based on the needlepoint array structure comprises the following steps:
1) cleaning a silicon wafer, and coating a hexamethyldisilazane adhesion layer;
2) uniformly spin-coating a positive photoresist, developing and hardening;
3) forming a silicon column array structure by adopting a deep silicon etching technology, and removing the photoresist by a plasma surface treatment method after finishing the forming;
4) corroding the silicon column array structure into a silicon needle tip array structure by adopting a wet etching technology;
5) depositing a layer of parylene film on the silicon needle tip array structure of the silicon wafer to complete the manufacturing of the silicon die; the thickness of the deposited parylene film is 500 nm;
6) mixing PDMS and a curing agent, stirring uniformly, extracting bubbles, pouring on a silicon mold, heating for curing, and uncovering the film; the mass ratio of PDMS to curing agent is 5:1, 7.5:1 or 10:1, and the heating curing mode is as follows: gradually heating at 30-40-50-60-70 deg.C for 5min at 30 deg.C, 40 deg.C, 50 deg.C and 60 deg.C, respectively, at 70 deg.C, keeping PDMS at a mass ratio of 5:1 to the curing agent for 1.5h, keeping PDMS at a mass ratio of 7.5:1 to the curing agent for 2h, and keeping PDMS at a mass ratio of 10:1 to the curing agent for 2.5 h;
7) depositing a layer of parylene film on the uncovered film to finish the manufacture of the PDMS groove needle point array structure mold; the thickness of the deposited parylene film is 500 nm;
8) mixing the graphene aqueous dispersion liquid subjected to ultrasonic treatment with PDMS, stirring uniformly by magnetic force, and finally evaporating the volatile solvent at a certain temperature; the concentration of the graphene aqueous dispersion liquid is 2mg/ml, the mass ratio of the graphene aqueous dispersion liquid to PDMS is 1: 5-1: 20, the temperature of evaporation treatment is 70 ℃, and the holding time is 1 h;
9) adding a curing agent into the mixture prepared in the step 8), uniformly stirring and extracting bubbles in the mixture; when the curing agent is added into the mixture, the curing agent is added according to the mass ratio of the PDMS to the curing agent of 5:1, 7.5:1 or 10: 1;
10) pouring the mixture prepared in the step 9) on a PDMS groove needle point array structure mould, standing for a period of time, heating for curing, and then uncovering the film to complete the manufacture of the graphene-PDMS flexible conductive substrate with the needle point array structure; the heating and curing mode is as follows: gradually heating at 30-40-50-60-70 ℃, wherein the temperature respectively lasts for 5min at 30 ℃, 40 ℃, 50 ℃ and 60 ℃, the mixture with the mass ratio of PDMS to curing agent of 5:1 lasts for 1.5h at 70 ℃, the mixture with the mass ratio of PDMS to curing agent of 7.5:1 lasts for 2h, and the mixture with the mass ratio of PDMS to curing agent of 10:1 lasts for 2.5 h;
11) depositing a layer of parylene film on a needle point array structure of a graphene-PDMS flexible conductive substrate, and then carrying out plasma surface treatment; the thickness of the deposited parylene film is 500 nm;
12) carrying out magnetron sputtering on a metal seed layer on the parylene film, and carrying out magnetron sputtering on a metal layer on the metal seed layer;
13) and coating a conductive silver adhesive layer on the back of the graphene-PDMS flexible conductive substrate, wherein the thickness of the conductive silver adhesive layer is 500 μm, and finally finishing the manufacture of the electrocardio dry electrode array of the graphene-PDMS flexible substrate based on the pinpoint structure.
2. The needle tip array structure-based graphene-PDMS flexible substrate electrocardio dry electrode according to claim 1, characterized in that: the length and width of the electrocardio dry electrode are 1 multiplied by 1 cm; the thickness of the graphene-PDMS flexible conductive substrate (1) is 300-500 μm; the distance between adjacent needle points in the needle point array structure (2) is 160-240 mu m; the diameter of the bottom circle of each needle point is 70 mu m, the diameter of the top circle is 5 mu m, and the height is 90 mu m; the thickness of the parylene film (3) is 500 nm; the thickness of the metal seed layer (4) is 150nm and the material is titanium; the thickness of the metal layer (5) is 20nm and the material is gold; the thickness of the conductive silver glue layer (6) is 500 mu m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810784683.2A CN108975266B (en) | 2018-07-17 | 2018-07-17 | graphene-PDMS flexible substrate electrocardio dry electrode based on needle tip array structure and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810784683.2A CN108975266B (en) | 2018-07-17 | 2018-07-17 | graphene-PDMS flexible substrate electrocardio dry electrode based on needle tip array structure and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108975266A CN108975266A (en) | 2018-12-11 |
| CN108975266B true CN108975266B (en) | 2020-11-10 |
Family
ID=64549383
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810784683.2A Active CN108975266B (en) | 2018-07-17 | 2018-07-17 | graphene-PDMS flexible substrate electrocardio dry electrode based on needle tip array structure and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108975266B (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109998533B (en) * | 2019-01-11 | 2020-09-04 | 休美(北京)微系统科技有限公司 | Flexible microneedle electrode array device and preparation method |
| EP3980740A4 (en) * | 2019-06-10 | 2022-08-10 | National University of Singapore | Composite structure for a pressure sensor and pressure sensor |
| TWI794527B (en) * | 2019-07-10 | 2023-03-01 | 國立成功大學 | Device comprising physical properties controlled by microstructure and method of manufacturing the same |
| CN110993577B (en) * | 2019-12-24 | 2022-02-15 | 上海交通大学 | PDMS microchannel heat sink, PDMS mold, silicon mold and preparation method thereof |
| CN111829697B (en) * | 2020-06-17 | 2022-07-05 | 华中科技大学 | Flexible pressure sensor with convex hemispherical structure and preparation method thereof |
| CN114660140B (en) * | 2020-12-23 | 2024-02-23 | 北京京东方技术开发有限公司 | Biological detection device, biological chip, microelectrode structure and preparation method thereof |
| CN112811386A (en) * | 2020-12-30 | 2021-05-18 | 哈尔滨工业大学（深圳） | Preparation method of 3d microelectrode |
| CN113080977B (en) * | 2021-03-25 | 2022-12-20 | 山东科技大学 | Preparation method of flexible electrode, flexible electrode and use method of flexible electrode |
| CN113274026A (en) * | 2021-04-01 | 2021-08-20 | 中国乐凯集团有限公司 | Flexible electrode and preparation method and application thereof |
| CN113217313B (en) * | 2021-04-22 | 2022-05-17 | 北京航空航天大学杭州创新研究院 | Response actuating device, preparation method and application |
| CN113588795B (en) * | 2021-06-24 | 2022-12-02 | 清华大学 | Flexible ultrasonic area array manufacturing method, flexible ultrasonic area array and ultrasonic imaging method |
| CN113647952A (en) * | 2021-08-18 | 2021-11-16 | 北京航空航天大学 | Flexible dry electrode made of silver/silver chloride nanowires and preparation method thereof |
| CN113697757B (en) * | 2021-08-26 | 2023-12-29 | 上海交通大学 | Metal composite flexible substrate and preparation method thereof |
| CN116421191A (en) * | 2023-03-08 | 2023-07-14 | 宁波康麦隆医疗器械有限公司 | Flexible integrated bioelectric signal sensor, detection method and device |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102499667A (en) * | 2011-10-20 | 2012-06-20 | 中国科学院半导体研究所 | Flexible skin surface dry electrode and preparation method thereof |
| CN102920452A (en) * | 2012-11-02 | 2013-02-13 | 上海交通大学 | Graphene-based flexible coronary electrocardio-electrode and preparation method thereof |
| CN105286855A (en) * | 2015-11-24 | 2016-02-03 | 深圳大学 | Preparation method of dry ECG (electrocardiogram) electrode |
| CN105615874A (en) * | 2016-03-01 | 2016-06-01 | 中国科学院半导体研究所 | Flexible electrocardio-electrode for dynamic electrocardiograph measurement and manufacturing method of flexible electrocardio-electrode for dynamic electrocardiograph measurement |
| CN106983507A (en) * | 2017-02-21 | 2017-07-28 | 中山大学 | A kind of flexible microelectrode arrays measured for body electrical signals and preparation method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8865288B2 (en) * | 2006-07-17 | 2014-10-21 | University Of Utah Research Foundation | Micro-needle arrays having non-planar tips and methods of manufacture thereof |
-
2018
- 2018-07-17 CN CN201810784683.2A patent/CN108975266B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102499667A (en) * | 2011-10-20 | 2012-06-20 | 中国科学院半导体研究所 | Flexible skin surface dry electrode and preparation method thereof |
| CN102920452A (en) * | 2012-11-02 | 2013-02-13 | 上海交通大学 | Graphene-based flexible coronary electrocardio-electrode and preparation method thereof |
| CN105286855A (en) * | 2015-11-24 | 2016-02-03 | 深圳大学 | Preparation method of dry ECG (electrocardiogram) electrode |
| CN105615874A (en) * | 2016-03-01 | 2016-06-01 | 中国科学院半导体研究所 | Flexible electrocardio-electrode for dynamic electrocardiograph measurement and manufacturing method of flexible electrocardio-electrode for dynamic electrocardiograph measurement |
| CN106983507A (en) * | 2017-02-21 | 2017-07-28 | 中山大学 | A kind of flexible microelectrode arrays measured for body electrical signals and preparation method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108975266A (en) | 2018-12-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108975266B (en) | graphene-PDMS flexible substrate electrocardio dry electrode based on needle tip array structure and preparation method thereof | |
| CN108318161B (en) | Wearable pressure sensor and manufacturing method thereof | |
| Solazzo et al. | PEDOT: PSS interfaces stabilised using a PEGylated crosslinker yield improved conductivity and biocompatibility | |
| US20190313933A1 (en) | Implantable flexible neural microelectrode comb, and preparation method and implantation method therefor | |
| CN100591388C (en) | Method of preparing micro needle array syringe | |
| CN109801739B (en) | High-precision patterned stretchable electrode and preparation method thereof | |
| WO2021115056A1 (en) | Flexible electrode and preparation method therefor | |
| WO2009014805A2 (en) | Micro-needle arrays having non-planar tips and methods of manufacture thereof | |
| CN109490998B (en) | Preparation method of double-layer chiral structure | |
| KR20140069144A (en) | Biocompatible electrode component and method for fabrication thereof | |
| CN110118624A (en) | A kind of pressure sensor and preparation method thereof | |
| US11926524B1 (en) | Methods, apparatus, and systems for fabricating solution-based conductive 2D and 3D electronic circuits | |
| CN113816362A (en) | Preparation of precisely patterned three-dimensional porous graphene, and precise transfer printing method and application thereof | |
| Yang et al. | An electrostatically self-assembled fluorinated molecule as a surface modification layer for a high-performance and stable triboelectric nanogenerator | |
| CN101229396A (en) | Blood vessel stent and fabricating method thereof | |
| Ruggiero et al. | Two-photon polymerization lithography enabling the fabrication of PEDOT: PSS 3D structures for bioelectronic applications | |
| KR101561961B1 (en) | All solid state planar type supercapacitor and fabrication method thereof | |
| CN105977038A (en) | Stretchable super capacitor with porous structure and preparation method of stretchable super capacitor | |
| US10984965B2 (en) | Fully biodegradable supercapacitor and method for manufacturing same | |
| CN112221010B (en) | Preparation method and application of silicon-based microneedle by metal-assisted wet etching | |
| CN115172589A (en) | Stretchable organic electrochemical transistor and preparation method thereof | |
| CN115196585A (en) | Magnetic control micro-nano robot and manufacturing method and application thereof | |
| JP2016531246A (en) | Method for making corrugated flexible diaphragm | |
| WO2021114287A1 (en) | Flexible electrode and preparation method therefor | |
| CN112618946A (en) | Pyramid-shaped flexible microneedle array and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |