阅读说明：本技术 一种可压缩应变传感器的制备方法 (Preparation method of compressible strain sensor ) 是由 顾俊杰 于 2019-08-21 设计创作，主要内容包括：本发明公开了一种制备应变传感器的方法,采用聚酰亚胺(PI)胶带用作掩模制作石墨烯应变层并采用自组装工艺将石墨烯应变层转移到聚二甲基硅氧烷(PDMS)衬底上,然后制作电极并封装,制得石墨烯应变传感器。本发明与现有技术相比具有更高的应变能力、更高的灵敏度因子、制备工艺简单、技术使其应用场景更宽阔。并且由于原材料易得、生产成本较低,可广泛用于可穿戴电子器件领域。(The invention discloses a method for preparing a strain sensor, which comprises the steps of manufacturing a graphene strain layer by using a Polyimide (PI) adhesive tape as a mask, transferring the graphene strain layer to a Polydimethylsiloxane (PDMS) substrate by using a self-assembly process, manufacturing an electrode and packaging to obtain the graphene strain sensor. Compared with the prior art, the invention has higher strain capacity, higher sensitivity factor, simple preparation process and wider application scene due to the technology. And because the raw materials are easy to obtain and the production cost is low, the wearable electronic device can be widely applied to the field of wearable electronic devices.)

1. A method for preparing a compressible strain sensor is characterized in that a polyimide PI adhesive tape is used as a mask to manufacture a graphene strain layer, the graphene strain layer is transferred to a polydimethylsiloxane PDMS substrate through a self-assembly process, then an electrode is manufactured and packaged, and the graphene strain sensor is manufactured;

The preparation method comprises the following steps:

(1) Carrying out plasma cleaning and hydrophilization treatment on the polydimethylsiloxane substrate;

(2) Mixing aqueous graphene and absolute ethyl alcohol, performing ultrasonic treatment and centrifugation, and taking supernatant of the solution to obtain graphene spreading liquid;

(3) Preparing deionized water with a clean liquid surface, sucking the graphene spreading liquid prepared in the step (2) by using a cleaned injector, spreading the graphene spreading liquid on the liquid surface of the deionized water, and standing the graphene spreading liquid after spreading to form a graphene layer; then placing the graphene layer in a membrane analyzer for compression to obtain a compact graphene solution;

(4) Laser etching the shape of a strain layer on a polyimide adhesive tape, adhering the etched polyimide adhesive tape to the polydimethylsiloxane substrate treated in the step (1), fixing the polydimethylsiloxane substrate at the front end of the dipping coating head, and then vertically lifting the polydimethylsiloxane substrate in the graphene solution to transfer a graphene film to obtain a graphene strain layer sample transferred to the substrate;

(5) heating the polydimethylsiloxane substrate after the treatment, then removing the polyimide adhesive tape, and preparing a graphene strain layer on the substrate;

(6) and respectively dripping silver paste electrodes at two ends of the graphene strain layer, connecting a copper wire to wait for the solidification of the silver paste, and then heating, curing and packaging the silver paste to obtain the graphene strain sensor.

2. the method according to claim 1, wherein in the step (2), the mass ratio of the aqueous graphene to the absolute ethyl alcohol is 1: 0.5-1; the ultrasonic treatment time is 30min-40 min.

3. The method of claim 1, wherein in step (3), the rate of compression is 2 milli-newtons per minute/meter.

4. The method according to claim 1, wherein in the step (3), the standing time is 15min to 20 min.

5. the method of claim 1, wherein in the step (3), the step of spreading the graphene spreading liquid on the liquid level of the deionized water comprises the following specific steps: and (3) spreading the graphene spreading liquid on the liquid surface of the deionized water drop by drop, and in the dropping process, adopting a left-right cyclic dropping mode to keep the surface pressure stable.

6. the method according to claim 1, wherein in the step (4), the vertical pulling speed is 2 to 5 mm/min.

7. The method according to claim 1, wherein in the step (4), the setting parameters of the immersion plating head are as follows: the descending height is-20 mm, the ascending height is 5mm, the descending speed and the ascending speed are both 4mm/min, and the descending residence time is 1 second.

8. The method of claim 1, wherein in step (5), the temperature of the heating is 70 ℃ to 80 ℃; the heating time is 3-5 min.

9. A compressible strain sensor prepared according to the method of any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of compressible sensors, in particular to a preparation method of a strain sensor based on an ordered monolayer technology.

Background

With the increasing application requirements of the information age, in the face of more and more special signals and the measurement of gas, pressure, humidity and the like in special environments, the novel sensor technology gradually develops towards the trend of microminiaturization, intellectualization, extension, portability and wearability. With the development of matrix materials, sensors become one of the important development directions of new-generation sensors, and are widely applied to aspects such as medical diagnosis, electronic skin, smart home and the like. Patent (CN107726971) discloses a strain sensor, which is manufactured by carbon nano fiber and has high maximum deformation amount but insufficient sensitivity. The patent (CN107655398A) discloses a high sensitivity tensile strain sensor and its manufacturing method, but its maximum strain range is small.

Disclosure of Invention

The object of the present invention is to provide a method of manufacturing a compressible strain sensor that addresses the deficiencies of the prior art. According to the invention, the Polyimide (PI) adhesive tape is used as a mask to manufacture the graphene strain layer, the graphene strain layer is transferred to a Polydimethylsiloxane (PDMS) substrate by adopting a self-assembly process, and the single-layer graphene film with excellent electrical and thermal properties is combined with PDMS with high optical transparency to prepare the compressible strain sensor with strong strain capacity and high sensitivity factor, so that the compressible strain sensor can be widely used for wearable electronic devices, and has good elasticity, stretchability and stability, the preparation process is simple, the preparation efficiency is high, and the quality of finished products is high.

the specific technical scheme for realizing the purpose of the invention is as follows:

A preparation method of a compressible strain sensor is characterized in that a Polyimide (PI) adhesive tape is used as a mask, the strain sensor is made into different shapes meeting the requirements of application scenes, and the method is suitable for a graphene preparation method of a self-assembly technology. The preparation method comprises the following steps:

(1) And carrying out plasma cleaning and hydrophilization treatment on the polydimethylsiloxane substrate.

(2) Mixing aqueous graphene and absolute ethyl alcohol, performing ultrasonic treatment and centrifuging, and taking supernatant of the solution to obtain graphene spreading liquid.

(3) And (3) preparing deionized water with a clean liquid surface, sucking the graphene spreading liquid prepared in the step (2) by using a clean injector, spreading the graphene spreading liquid on the liquid surface of the deionized water, and standing the graphene spreading liquid after spreading to form the graphene layer. And then placing the graphene layer in a membrane analyzer for compression to obtain a compact graphene solution.

(4) And (3) performing laser etching on a strain layer shape on a Polyimide (PI) adhesive tape, adhering the etched Polyimide (PI) adhesive tape to the polydimethylsiloxane substrate treated in the step (1), fixing the Polyimide (PI) adhesive tape at the front end of the dipping coating head, and vertically pulling the polydimethylsiloxane substrate in the graphene solution obtained in the step (3) to transfer the graphene film to obtain a graphene strain layer sample transferred to the substrate.

(5) and heating the polydimethylsiloxane substrate after the treatment, then removing the polyimide adhesive tape, and preparing the graphene strain layer on the substrate.

(6) And respectively dripping silver paste electrodes at two ends of the graphene strain layer, connecting a copper wire to wait for the solidification of the silver paste, and then heating, curing and packaging the silver paste to obtain the graphene strain sensor.

In the step (1), the specific operation steps of the plasma cleaning and hydrophilization treatment are to utilize a plasma cleaning machine to realize the plasma cleaning of the polydimethylsiloxane substrate and remove the surface chemical substance residues and the natural oxide layer.

In the step (2), the mass ratio of the aqueous graphene to the absolute ethyl alcohol is 1: 0.5-1; preferably, 1: 1.

In the step (2), the ultrasonic treatment time is 30-40 min; preferably, it is 30 min.

In the step (3), the step of spreading the graphene spreading liquid on the liquid level of the deionized water specifically comprises: and (3) spreading the graphene spreading liquid on the liquid surface of the deionized water drop by drop, and in the dropping process, adopting a left-right cyclic dropping mode to keep the surface pressure stable.

In the step (3), the compression speed is 2 milli-newtons per minute/meter.

In the step (3), the standing time is 15-20 minutes; preferably, it is 15 minutes.

The purpose of the standing was to remove ethanol.

In the step (4), the setting parameters of the dip coating head are preferably as follows: the descending height is-20 mm, the ascending height is 5mm, the descending speed and the ascending speed are both 4mm/min, and the descending residence time is 1 second.

in the step (4), the speed of vertical pulling is 2-5 mm/min; preferably, it is 2 mm/min.

The vertical pulling in the step (4) aims to enable the graphene strain layer to be uniformly stressed and separated from the liquid surface, and the sample is prevented from being transversely torn due to surface tension.

In step (5), the heating is preferably performed on a heating platform.

Wherein the purpose of the heating is to remove moisture carried in the transfer process on the substrate.

In the step (5), the heating temperature is 70-80 ℃; preferably, it is 80 ℃.

In the step (5), the heating time is 3-5 minutes; preferably, it is 5 minutes.

The method has the beneficial effects that the graphene strain layer is transferred to the Polydimethylsiloxane (PDMS) substrate by adopting a self-assembly process, and the single-layer graphene film with excellent electrical and thermal properties is combined with the PDMS with high optical transparency to prepare the compressible strain sensor with strong strain capacity, high sensitivity factor, and the capability of being widely used for wearable electronic devices, and the strain sensor has good elasticity, stretchability and stability, and is simple in preparation process, high in preparation efficiency and high in finished product quality.

Drawings

FIG. 1 is a process flow diagram of the present invention;

FIG. 2 is a schematic diagram of a PI tape with an etched pattern;

FIG. 3 is a schematic view of a substrate structure to which a PI tape is attached;

FIG. 4 is a graph of area-surface pressure of a strained layer of graphene;

FIG. 5 is a graph of a graphene strain layer transfer process;

Fig. 6 is a schematic diagram of a sensor structure.

Detailed Description

the present invention will be described in further detail with reference to the following specific examples and drawings, and the present invention is not limited to the following examples. Variations and advantages that may occur to those skilled in the art may be incorporated into the invention without departing from the spirit and scope of the inventive concept, and the scope of the appended claims is intended to be protected.

Referring to fig. 1 and 2, the present invention will be further described in detail by taking the specific preparation of the graphene strain sensor as an example.