CN113252741A - Flexible humidity sensor and preparation method thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种基于疏水多孔聚四氟乙烯隔离和保护的柔性湿度传感器及其制备方法，传感器由下至上包括疏水多孔聚四氟乙烯衬底，金属电极层，疏水多孔聚四氟乙烯隔离层，氧化石墨烯敏感层及疏水多孔聚四氟乙烯材料保护层。本发明制备的湿度传感器由于在金属电极层和湿敏材料层之间有一层绝缘的疏水多孔聚四氟乙烯，可以有效的减小高湿度下器件的电容损耗，另外在最外层有一层疏水多孔聚四氟乙烯材料保护层，可以防水防污，具有良好的透气性，同时又不会影响器件的性能。

The invention discloses a flexible humidity sensor based on hydrophobic porous polytetrafluoroethylene isolation and protection and a preparation method thereof. The sensor comprises a hydrophobic porous polytetrafluoroethylene substrate, a metal electrode layer, and a hydrophobic porous polytetrafluoroethylene isolation from bottom to top layer, graphene oxide sensitive layer and hydrophobic porous polytetrafluoroethylene material protective layer. The humidity sensor prepared by the present invention has a layer of insulating hydrophobic porous polytetrafluoroethylene between the metal electrode layer and the humidity-sensitive material layer, which can effectively reduce the capacitance loss of the device under high humidity. The protective layer of porous polytetrafluoroethylene material is waterproof and antifouling, and has good air permeability without affecting the performance of the device.

Description

Flexible humidity sensor and preparation method thereof

Technical Field

The invention relates to the technical field of semiconductor processes, in particular to a flexible humidity sensor and a preparation process thereof.

Background

Humidity is a common environmental parameter in life, and humidity sensors are widely applied to the aspects of meteorology, semiconductors, food processing, medical treatment and the like. The capacitive humidity sensor is researched by broad researchers due to low power consumption, high performance and long-term stability, however, the leakage loss in the dielectric material can increase the total power consumption of the device and reduce the performance of the device, and on the other hand, the surface contamination of the humidity sensitive material can also rapidly reduce the sensitivity of the device.

In 2005, jin Wang et al prepared a capacitive humidity sensor using nano barium titanate as a sensitive material, and the test results showed that there was dielectric loss in almost all relative humidity ranges, and with the increase of relative humidity, the peak value of dielectric loss would move in the high frequency direction, and at the same time, the sensor had no protective layer, and the humidity sensitive layer was easily contaminated. In 2008, to Zhang et al prepared a humidity sensor with polypyrrole as a sensitive material on an alumina ceramic substrate, and observed similar dielectric loss characteristics. In order to protect the humidity sensitive layer from being polluted and prevent high-humidity water vapor from condensing on the humidity sensitive layer, a protective layer is formed on the humidity sensitive layer by spin coating ethyl cellulose acetate solution, but the protective layer also has certain water absorption and can influence the humidity sensitive characteristic of a device.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the capacitance loss of the capacitive humidity sensor due to humidity increases the power consumption of the device and reduces the performance of the device. The humidity sensitive layer is easily polluted by the outside, and the reliability of the device is not high.

In order to solve the technical problem, the invention provides a flexible humidity sensor which comprises a hydrophobic porous polytetrafluoroethylene substrate, a metal electrode layer, a hydrophobic porous polytetrafluoroethylene isolation layer, a humidity sensitive material layer and a hydrophobic porous polytetrafluoroethylene material protection layer from bottom to top;

the metal electrode layer is positioned on the hydrophobic porous polytetrafluoroethylene substrate, the hydrophobic porous polytetrafluoroethylene isolation layer is arranged between the metal electrode layer and the graphene oxide sensitive layer, and the hydrophobic porous polytetrafluoroethylene material protection layer is arranged on the graphene oxide sensitive layer.

Preferably, the metal electrode layer is a silver electrode, and the metal electrode layer is formed on the hydrophobic porous polytetrafluoroethylene substrate by a screen printing process.

Preferably, the thickness of the hydrophobic porous polytetrafluoroethylene substrate is between 0.18mm and 0.22 mm; the pore diameter of the micropores is between 0.22um and 0.8 um.

Preferably, the humidity sensitive material layer is made of graphene oxide sensitive material.

The invention discloses a preparation method of a flexible humidity sensor, which comprises the following specific steps:

step S1, printing a layer of metal electrode on a hydrophobic porous polytetrafluoroethylene substrate by utilizing a screen printing process;

step S2, forming a hydrophobic porous polytetrafluoroethylene isolating layer on the metal electrode by utilizing an electrostatic spinning process;

s3, performing vacuum suction filtration on the graphene oxide aqueous dispersion on the hydrophobic porous polytetrafluoroethylene isolation layer to form a graphene oxide sensitive layer serving as a humidity sensitive material layer;

and step S4, forming a hydrophobic porous polytetrafluoroethylene material protective layer on the humidity sensitive material layer through an electrostatic spinning process.

The invention has the beneficial effects that: the hydrophobic porous polytetrafluoroethylene material has very low surface adsorption energy, a large contact angle between water and the hydrophobic porous polytetrafluoroethylene material, can effectively isolate liquid water, has excellent electrical insulation performance, and can reduce the capacitance loss of devices. The hydrophobic polytetrafluoroethylene layer prepared by the electrostatic spinning process has a net-shaped porous structure, is breathable and waterproof, and can be simultaneously used for isolation and protection in a moisture-sensitive capacitor structure.

The hydrophobic porous polytetrafluoroethylene isolating layer is formed on the metal electrode layer through electrostatic spinning, so that the capacitance loss of the device under high humidity can be effectively reduced, and the performance of the device is improved. In addition, the outermost layer forms a hydrophobic porous polytetrafluoroethylene material protective layer through electrostatic spinning, and the waterproof and antifouling fabric has good air permeability.

Drawings

FIG. 1 is a schematic front view of a flexible humidity sensor according to the present invention;

FIG. 2 is a schematic cross-sectional view of a flexible humidity sensor according to the present invention.

Wherein: the humidity sensor comprises a 1-hydrophobic porous polytetrafluoroethylene substrate, a 2-metal electrode layer, a 3-hydrophobic porous polytetrafluoroethylene isolation layer, a 4-humidity sensitive material layer and a 5-hydrophobic porous polytetrafluoroethylene material protection layer.

Detailed Description

In order that the invention may be better understood, the invention will now be further described by way of the following examples, which are intended to be illustrative only and not limiting:

as shown in fig. 1 and 2, the flexible humidity sensor provided by the present invention comprises, from bottom to top, a hydrophobic porouspolytetrafluoroethylene substrate 1, ametal electrode layer 2, a hydrophobic porouspolytetrafluoroethylene isolation layer 3, a humiditysensitive material layer 4, and a hydrophobic porous polytetrafluoroethylenematerial protection layer 5;

themetal electrode layer 2 is positioned on the hydrophobicporous polytetrafluoroethylene substrate 1, the hydrophobic porouspolytetrafluoroethylene isolation layer 3 is positioned between themetal electrode layer 2 and the humiditysensitive material layer 4, the hydrophobic porous polytetrafluoroethylenematerial protection layer 5 is also arranged on the humiditysensitive material layer 4, and the humiditysensitive material layer 4 is electrically connected with themetal electrode layer 2; the humidity sensitive material is a graphene oxide sensitive material.

In the embodiment, themetal electrode layer 2 is a tiled interdigital electrode, is made of a silver material, and is formed on the hydrophobicporous polytetrafluoroethylene substrate 1 through a screen printing process; the hydrophobic porouspolytetrafluoroethylene isolating layer 3 is formed on themetal electrode layer 2 through an electrostatic spinning process; the humiditysensitive material layer 4 is formed on the hydrophobic porouspolytetrafluoroethylene isolation layer 3 through vacuum filtration of graphene oxide dispersion.

In the embodiment, the thickness of the hydrophobicporous polytetrafluoroethylene substrate 1 is between 0.18mm and 0.22 mm; the pore diameter of the micropores is between 0.22um and 0.8 um.

The invention discloses a preparation method of a flexible humidity sensor, which comprises the following specific steps:

step S1, forming ametal electrode layer 2 on the hydrophobicporous polytetrafluoroethylene substrate 1 by utilizing a screen printing process;

step S2, forming a hydrophobic porouspolytetrafluoroethylene isolation layer 3 on themetal electrode layer 2 by utilizing an electrostatic spinning process, wherein the hydrophobic porouspolytetrafluoroethylene isolation layer 3 covers themetal electrode layer 2 and the area where themetal electrode layer 2 is located;

s3, performing vacuum filtration on the hydrophobic porouspolytetrafluoroethylene isolation layer 3 to form a graphene oxide sensitive layer serving as a humiditysensitive material layer 4, wherein 0.1ml of graphene oxide aqueous dispersion with the concentration of 0.5mg/ml is formed in a vacuum filtration manner;

and S4, forming a hydrophobic porous polytetrafluoroethylenematerial protection layer 5 on the humiditysensitive material layer 4 through an electrostatic spinning process, wherein the hydrophobic porous polytetrafluoroethylenematerial protection layer 5 covers the humiditysensitive material layer 4 and the area where the hydrophobic porouspolytetrafluoroethylene isolation layer 3 is located.

The invention is not described in detail, but is well known to those skilled in the art.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (5)

Translated fromChinese

1.一种柔性湿度传感器,其特征在于，由下至上包括，疏水多孔聚四氟乙烯衬底(1)、金属电极层(2)、疏水多孔聚四氟乙烯隔离层(3)、湿度敏感材料层(4)和疏水多孔聚四氟乙烯材料保护层(5)。1. A flexible humidity sensor, characterized in that it comprises, from bottom to top, a hydrophobic porous polytetrafluoroethylene substrate (1), a metal electrode layer (2), a hydrophobic porous polytetrafluoroethylene isolation layer (3), a humidity sensitive A material layer (4) and a protective layer (5) of a hydrophobic porous polytetrafluoroethylene material.2.根据权利要求1所述一种柔性湿度传感器,其特征在于，所述金属电极层(2)是银电极，并通过丝网印刷工艺形成于疏水多孔聚四氟乙烯衬底1之上。2 . The flexible humidity sensor according to claim 1 , wherein the metal electrode layer ( 2 ) is a silver electrode and is formed on the hydrophobic porous polytetrafluoroethylene substrate 1 by a screen printing process. 3 .3.根据权利要求1所述一种柔性湿度传感器,其特征在于，所述疏水多孔聚四氟乙烯衬底(1)的厚度在0.18mm-0.22mm之间，微孔孔径在0.22um-0.8um之间。3. The flexible humidity sensor according to claim 1, wherein the thickness of the hydrophobic porous polytetrafluoroethylene substrate (1) is between 0.18mm-0.22mm, and the micropore diameter is between 0.22um-0.8 between um.4.根据权利要求1所述一种柔性湿度传感器,其特征在于，所述湿度敏感材料层(4)采用的是氧化石墨烯敏感材料。4 . The flexible humidity sensor according to claim 1 , wherein the humidity sensitive material layer (4) adopts a graphene oxide sensitive material. 5 .5.一种如权利要求4所述柔性湿度传感器的制备方法，其特征在于，包括如下步骤：5. A preparation method of a flexible humidity sensor as claimed in claim 4, characterized in that, comprising the steps of:步骤S1、利用丝网印刷工艺在疏水多孔聚四氟乙烯衬底(1)上形成金属电极层(2)；Step S1, using a screen printing process to form a metal electrode layer (2) on the hydrophobic porous polytetrafluoroethylene substrate (1);步骤S2、利用静电纺丝工艺在金属电极层(2)上形成一层疏水多孔聚四氟乙烯隔离层(3)。Step S2, using an electrospinning process to form a hydrophobic porous polytetrafluoroethylene isolation layer (3) on the metal electrode layer (2).步骤S3、在疏水多孔聚四氟乙烯隔离层(3)上真空抽滤氧化石墨烯水分散液，形成氧化石墨烯敏感层作为湿度敏感材料层(4)；Step S3, vacuum-filtering the graphene oxide aqueous dispersion on the hydrophobic porous polytetrafluoroethylene isolation layer (3) to form a graphene oxide sensitive layer as the humidity sensitive material layer (4);步骤S4、在湿度敏感材料层(4)上通过静电纺丝工艺形成疏水多孔聚四氟乙烯材料保护层(5)。Step S4, forming a protective layer (5) of a hydrophobic porous polytetrafluoroethylene material on the moisture-sensitive material layer (4) by an electrospinning process.

Images