A Self-powered Temperature-sensitive Electronic Skin Based On Tribotronic Effect Of PANI/PDMS Nanostructures

Skin is the largest organ of human body,and also one of the most important organs.Its main functions are perspiration,protection and perception.There are abundant neurons under the skin.Through these neurons,the skin can respond sensitively to the external stimulation or the coming danger.In the field of scientific research and sensor,scientists pay more and more attention to the research of a kind of sensor which can realize the similar human skin perception ability.This kind of sensor,which is similar to skin perception,can sense the biological information in pressure,gas,pH and sweat.In recent years,with the continuous development of economy and industry,global warming is more serious.Global warming makes the "urban heat island effect" more and more obvious.The "urban heat island effect" has greatly increased the incidence of heat radiation disease,which can rapidly develop into multiple organ dysfunction and death.Therefore,it is urgent to monitor and prevent the disease.Although a common thermometer can measure the temperature of human body,it is not easy to carry or need to replace batteries frequently.So a portable,non power bound wearable device can solve this problem.With the advent of triboelectric nanogenerators,they can collect the mechanical energy of people which generated in daily life,such as the energy generated by human movement and muscle contraction.Vibrational energy,such as that produced by sound and ultrasonic waves;Fluid energy,such as fluid flow,blood flow,and arterial contraction.As a result,a variety of new electronic skins(olfactory,visual,pressure,etc.)have been created to replace the human senses,but temperature electronic skins have not appeared.In order to be able to monitor and enable people to detect and treat heat sickness in time,we designed a new type of temperature electronic skin.In this experiment,a kind of flexible temperature sensitive electronic skin based on tribological effect was designed with poly anil ine(PANI)and polydimethylsiloxane(PDMS)nanomaterials as the core,and the human body temperature was monitored.Specific work content is as follows:(1)preparation of flexible,self-powered,temperature-sensitive electronic skin:the preparation of electronic skin is completed through a series of technological means including lithography,development,PDMS soft model method,inductively coupled plasma method,wet etching,electrochemical deposition,electron beam evaporation and coating.PDMS is both a flexible substrate and a negative friction material.Patterned Cu electrodes are embedded on the top of the PDMS,and electrochemical deposition of PANI is carried out on the surface of Cu electrodes.The back of PDMS was coated with a Cu electrode of 100 nm thickness by electron beam evaporation film for signal acquisition.As a temperature sensing material and a friction positive material,PANI is the core material in the whole electronic skin.(2)Characterization and temperature sensing test of electronic skin:after successful preparation of electronic skin,it was characterized by SEM.Under SEM,it was observed that PANI on the electronic skin surface was evenly coated on the flexible electrode,and there was a gap between PANI and PDMS,which strongly demonstrated that contact separation friction could be conducted between them.Then,the surface of PDMS under SEM was nanoparticles,which effectively increased the contact area of friction.Next,we first tested the triboelectric output performance of the electronic skin and found that the triboelectric output was different at different temperatures.Then a number of experiments were conducted between 30℃ and 44℃.It was found that the triboelectric output current of the electronic skin increased with the increase of temperature and decreased with the decrease of temperature,and the temperature sensing was dynamic and repeatable.(3)Electronic skin and human body temperature test:before the application of human skin,we conducted different frequency,different Angle and temperature resolution test.The experiment found that the low frequency had no effect on the output of electronic skin.The larger the bending Angle is,the larger the output of the electronic skin will be,so maintaining an Angle during the temperature sensing test can eliminate its influence.The temperature resolution was gradually improved in the test,and it was finally found that after changing 0.4℃,there was no significant difference in the signal,so the temperature resolution of the electronic skin was 0.4℃.Finally,the electronic skin was fixed at the joint of the arm,and the bending of the human arm drove the electronic skin and conducted skin surface temperature sensing.The output of the electronic skin at 36.5℃ and 42.0℃ was 10.25 and 13.04 nA,respectively.It realizes the monitoring of human body surface temperature and provides an innovative idea for the monitoring and discovery of thermal radiation.