| In recent years,flexible sensing technology has developed rapidly and different flexible sensors have gradually entered people's field of vision.Flexible sensors make up for the shortcomings of rigid sensing and they can realize real-time monitoring of human physiological information and apply to many special occasions such as medical treatment.The flexible temperature sensor can be used as a wearable device to monitor the body temperature of different parts of the human body in real time.The flexible strain sensor can not only monitor the strain of the key parts of the human body,but also realize the real-time measurement of heart rate;the flexible acetone gas sensor can detect the concentration of acetone exhaled by the human body.By moniting them,they not only allow people to conduct a simple self-analysis of their own health,but also provide a basis for doctors to judge the disease.For example,lung cancer is one of the most serious malignant tumors to human health.Patients with early stage lung cancer are often characterized by elevated body temperature and increased heart rate.At the same time,the concentration of acetone gas in exhaled gases of lung cancer patients generally exceeds 1.0 ppm.The normal person exhaled the acetone gas concentration to 0.3-0.9 ppm.With its large surface-to-volume ratio,unique thermal properties,excellent carrier mobility and modification,graphene can be combined with flexible sensors to improve the performance of flexible sensors.Based on the above,this article mainly studies the following:1.Reduced graphene oxide was prepared by reducing graphene oxide with environmentally friendly ascorbic acid,and the prepared reduced graphite oxide?r-GO?was characterized by SEM,XRD and Raman.At the same time,a flexible film type temperature sensor was prepared by using r-GO as temperature sensitive material.The material was prepared with a flexible film type temperature sensor.The sensor achieves a temperature measurement from 30°C to 100°C with a sensitivity of 0.6345%°C-1.The sensor has good mechanical properties and is not affected by external pressure,which greatly enhances the anti-interference ability of the sensor,improves the accuracy of the sensor,and facilitates temperature monitoring of the sensor on any curved surface.2.The conductivity of graphene prepared by redox method is low.In this paper,r-GO and PEDOT:PSS were combined at room temperature by ultrasonic vibration method to prepare a composite material of r-GO/PEDOT:PSS.The conductivity of r-GO is improved and a new sheet structure is formed.Two kinds of flexible strain sensors were prepared by using r-GO and r-GO/PEDOT:PSS as sensitive materials.The sensors were then pre-stretched to demonstrate the importance of pre-stretching on the recoverable conductance and reliability of the sensor;and the strain factor?sensitivity?in the strain range of 10%to 70%for both sensors was performed.In comparison,it is found that the sensitivity of the strain sensor of r-GO/PEDOT:PSS is much higher than the r-GO strain sensor.Finally,the r-GO/PEDOT:PSS sensor was characterized by the human body,which realizes the test of wrist bending and heart rate.It provides an experimental basis for its application to wearable devices and detection of diseases;3.High surface-to-volume ratio three-dimensional r-GO/Na-ZnO was prepared by simple solution method at a lower temperature.Using the prepared r-GO/Na-ZnO as sensitive materials,a flexible sensor capable of detecting the concentration of acetone gas at normal temperature was designed.The sensor has excellent response to 10 ppm to 200 ppm acetone gas and has good repeatability and long-term stability in a 150 ppm acetone atmosphere.At the same time,the sensor can respond to a minimum of 0.2 ppm of acetone gas and is insensitive to three different organic exhaled volatile gases?ethanol,methanol and isopropanol?.This means that the sensor can be used in more applications,especially for the detection of human diseases such as diabetes and lung cancer. |
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