阅读说明：本技术 一种微针离子凝胶压力传感器件的制备方法 (Preparation method of microneedle ionic gel pressure sensing device ) 是由 李秋瑾 董裕 巩继贤 于 2021-09-09 设计创作，主要内容包括：本发明涉及一种微针离子凝胶压力传感器件的制备方法,属于复合材料领域。这种具有特殊结构传感器的主要特点是应变范围广、灵敏度高和响应及时等,不仅能够实现对人体大运动的实时监测,还能对人体微小的生理信号进行监测。本发明中微针离子凝胶压力传感器件的制备方法为,先将含有大量离子液体的前驱体溶液导入模具中,然后通过紫外聚合的方法制得微棱锥结构的离子凝胶,最后在其两端连接导线制备得到。本发明不仅制备方法简单,绿色环保,且制得的压力传感器具有较高的灵敏度和较宽的压力响应范围,为未来柔性压力传感器在人体运动监测和医疗健康监测等领域的广泛应用提供了研究思路。(The invention relates to a preparation method of a microneedle ionic gel pressure sensor, belonging to the field of composite materials. The sensor with the special structure has the main characteristics of wide strain range, high sensitivity, timely response and the like, not only can realize real-time monitoring of large motion of a human body, but also can monitor tiny physiological signals of the human body. The preparation method of the microneedle ionic gel pressure sensor comprises the steps of introducing a precursor solution containing a large amount of ionic liquid into a mold, preparing ionic gel with a micro pyramid structure by an ultraviolet polymerization method, and finally connecting conducting wires at two ends of the ionic gel to prepare the microneedle ionic gel pressure sensor. The preparation method is simple and environment-friendly, and the prepared pressure sensor has high sensitivity and a wide pressure response range, so that a research idea is provided for the wide application of the flexible pressure sensor in the fields of human motion monitoring, medical health monitoring and the like in the future.)

1. A preparation method of a microneedle ionic gel pressure sensing device comprises the following steps:

(1) preparing a precursor solution: tetraethyl orthosilicate (TEOS), 1-butyl-3-methylimidazolium tetrafluoroborate ([ Bmim) are added in sequence][BF₄]) Under the condition of introducing nitrogen, magnetically stirring the solution for a certain time to obtain an evenly mixed ionic solution, and placing the ionic solution in a constant-temperature oven in a dark place for continuously heating for a period of time to obtain a precursor solution;

(2) selecting a mould: selecting a die with a specific size and a specific material;

(3) preparing the microneedle array ionic gel: and (2) dripping the precursor solution prepared in the step (1) into a selected film, placing the film in an oven for a period of time, and irradiating the film by using ultraviolet light with certain intensity to ensure that the film is fully polymerized. Finally, drying for a period of time to obtain the microneedle array ionic gel;

(4) preparing an ionic gel-based sensor of the microneedle array: and (4) taking the ionic gel in the step (3) as a sensing element, and connecting wires at two ends of the sensing element to obtain the ionic gel-based sensor.

2. The method of claim 1, wherein the amount of tetraethyl orthosilicate (TEOS) used in the step (1) is 0.1-1g, the amount of 1-butyl-3 methyl-imidazolium tetrafluoroborate used in the step (5-10 g), the amount of N, N' -Methyleneacrylamide (MBA) used in the step (1) is 1-2g, the amount of N, N-dimethylacrylamide used in the step (0.4% MBA) is 1-3mg, the concentration of the hydrochloric acid solution is 1-20mmol/L, the amount of the hydrochloric acid solution is 0.1-1mL, the nitrogen gas introduction time is 10-30min, the magnetic stirring time is 1-2h, the constant oven temperature condition is 10-60 ℃, and the heating time is 1-30 h.

3. The method according to claim 1, wherein the mold in the step (2) has a height of 1-500 μm, a length of a bottom edge of the microneedle is 1-500 μm, a width of the bottom edge of the microneedle is 1-500 μm, the microneedle array is 10 x 10, and the material is a PDMS material with strong hydrophobicity.

4. The method for preparing a microneedle ionic gel pressure sensor according to claim 1, wherein the amount of the precursor solution dropped in the step (3) is 1-5mL, the oven is placed in a vacuum oven for a period of time, the intensity of the ultraviolet light source is 75%, the irradiation time is 1-30min, the ionic gel is dried in vacuum, the drying temperature is 10-60 ℃, and the drying time is 1-30 h.

Technical Field

The invention relates to a preparation method of a microneedle ionic gel pressure sensor, belonging to the field of composite materials.

Background

In recent years, with the vigorous development of the fields of novel medical monitoring, human-computer interaction, wearable electronic products and the like, the flexible pressure sensor is receiving attention. The conventional thin film based pressure sensor has been studied for a certain degree, but generally, in order to facilitate the application of the pressure sensor, the thickness of the sensor is only several tens to several hundreds micrometers, and the distance that can be compressed is very limited, so the thin film based pressure sensor generally shows a low sensitivity. The fabrication of a pressure sensor with high sensitivity cannot be realized by a simple thin film structure. The microstructure is constructed on the film, and the stressed deformation range is greatly enlarged by increasing the contact area when the film is stressed, so that the effect of improving the sensitivity of the sensor is achieved. The ionic gel with the micro pyramid array is widely researched in the field of flexible pressure sensors due to the unique structure of the ionic gel.

Disclosure of Invention

The invention aims to solve the problems of low sensitivity and small strain range of the existing film-based sensor and provides a preparation method of a micro-needle ionic gel pressure sensing device. The sensor with the special structure has the main characteristics of wide strain range, high sensitivity, timely response and the like, not only can realize real-time monitoring of large motion of a human body, but also can monitor tiny physiological signals of the human body. The preparation method of the microneedle ionic gel pressure sensor comprises the steps of introducing a precursor solution containing a large amount of ionic liquid into a mold, preparing ionic gel with a micro pyramid structure by an ultraviolet polymerization method, and finally connecting conducting wires at two ends of the ionic gel to prepare the microneedle ionic gel pressure sensor. The preparation method is simple and environment-friendly, and the prepared pressure sensor has high sensitivity and a wide pressure response range, so that a research idea is provided for the wide application of the flexible pressure sensor in the fields of human motion monitoring, medical health monitoring and the like in the future.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

(1) preparing a precursor solution: tetraethyl orthosilicate (TEOS), 1-butyl-3-methylimidazolium tetrafluoroborate ([ Bmim) are added in sequence][BF₄]) N, N' -methylene acrylamide (MBA), N-dimethylacrylamide, ketoglutaric acid and hydrochloric acid solution, introducing nitrogen gasUnder the condition (1), magnetically stirring for a certain time to obtain an ion solution which is uniformly mixed, and keeping away from light, putting the ion solution in a constant-temperature oven and continuously heating for a period of time to obtain a precursor solution;

(2) selecting a mould: selecting a die with a specific size and a specific material;

(3) preparing the microneedle array ionic gel: and (2) dripping the precursor solution prepared in the step (1) into a selected film, placing the film in an oven for a period of time, and irradiating the film by using ultraviolet light with certain intensity to ensure that the film is fully polymerized. Finally, drying for a period of time to obtain the microneedle array ionic gel;

(4) preparing an ionic gel-based sensor of the microneedle array: and (4) taking the ionic gel in the step (3) as a sensing element, and connecting wires at two ends of the sensing element to obtain the ionic gel-based sensor.

Preferably, tetraethyl orthosilicate (TEOS) is used in an amount of 0.1 to 1g, 1-butyl-3 methyl-imidazolium tetrafluoroborate is used in an amount of 5 to 10g, N, N' -Methyleneacrylamide (MBA) is used in an amount of 1 to 2g, N, N-dimethylacrylamide is used in an amount of 0.4% MBA, ketoglutaric acid is used in an amount of 1 to 3mg, and a hydrochloric acid solution is used in an amount of 1 to 20mmol/L and in an amount of 0.1 to 1mL in step (1). Introducing nitrogen for 10-30min, magnetically stirring for 1-2 hr, keeping the oven temperature at 10-60 deg.C, and heating for 1-30 hr;

preferably, the size of the mold in the step (2) is that the height of the microneedle is 1-500 μm, the length of the bottom edge of the microneedle is 1-500 μm, the width of the bottom edge of the microneedle is 1-500 μm, the microneedle array is 10 × 10, and the material is a PDMS material with strong hydrophobicity;

preferably, the amount of the precursor solution dropped in the step (3) is 1-5mL, the oven is placed for a period of time, the vacuum oven is placed for 1-60min, the intensity of the ultraviolet light source is 75%, and the irradiation time is 1-30 min. The drying mode of the ionic gel is vacuum drying, the drying temperature is 10-60 ℃, and the drying time is 1-30 h.

Due to the adoption of the technical scheme, the method has the following beneficial effects:

(1) the main raw material used in the preparation process of the precursor solution is ionic liquid, the ionic liquid has the characteristics of difficult volatilization, good thermal stability, difficult combustion, high conductivity, greenness, no pollution and the like, and the prepared precursor solution not only can provide good conductivity, but also has better environmental friendliness;

(2) the sensing element prepared by the invention is ionic gel which is a novel flexible transparent material which is formed by compounding ionic liquid and polymer and can keep excellent conductivity at extreme temperature, and the sensing element not only has unique ionic conductivity and thermal stability, but also has good mechanical property and high sensing performance;

(3) the prepared ionic gel with the specific microneedle array structure has excellent performances such as high sensitivity, wide strain response range and the like, and the preparation method is simple, green and environment-friendly;

(4) the ionic gel-based sensor prepared by the invention has wide application prospect in the fields of real-time motion monitoring of human bodies, medical health detection and the like.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1: is a graph showing the results of example 1 of the present invention.

FIG. 2: is a graph showing the results of example 2 of the present invention.

FIG. 3: is a graph showing the results of example 3 of the present invention.

Detailed Description

The invention is described below in connection with specific embodiments with the attached figures. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. In addition, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications in the components and amounts of the materials used in these embodiments can be made without departing from the spirit and scope of the invention.

Example 1: and (3) selecting a specific mould, and preparing the microneedle array ionic gel by adopting an ultraviolet polymerization method. As shown in fig. 1, the precursor solution is completely cured under the irradiation of an ultraviolet lamp to form a neat micro-needle array ionic gel.

Example 2: connecting two ends of the prepared ionic gel with a lead to obtain the ionic gel-based sensor, and attaching the ionic gel-based sensor to the wrist of a human body to collect pulse signals at the wrist. As shown in figure 2, the prepared ionic gel-based sensor has certain flexibility and can be well contacted with a human body.

Example 3: the ionic gel based sensing device adopting the micro-needle array is used for monitoring the pulse at the wrist of a human body in real time. As shown in fig. 3, the sensor can convert the pulse signal of the human body into an electrical signal and can rapidly respond to each pulse, thereby realizing real-time monitoring of the pulse at the wrist of the human body.