Preparation Of Patterned Elastomer Surface Via Hot-pressing Method And Its Application

Wearable flexible pressure sensors have sparked a considerable interest for their promising applications（e.g.,disease diagnosis,personal healthcare,human-machine interfaces,speech recognition and so on）.Up to now,various flexible pressure sensors have been developed based on different sensing mechanisms,such as transistor sensing,piezoresistivity,piezoelectricity,triboelectricity,capacitive and optical sensing.The preparation process of capacitive and piezoresistive flexible pressure sensors is simple,and their pressure response performance is very excellent（especially the short response time and high working stability）.However,the pressure sensitivity of common capacitive and piezoresistive flexible pressure sensors can’t meet the needs of practical application.At present,the most effective way to improve the response sensitivity of sensors is to prepare micropatterns in the dielectric layer or electrode.To enhance their sensitivity,the dielectric layers and electrodes are generally micro-structured via various methods（e.g.,lithography,microcontact printing,direct writing technique,self-assembly of block copolymers,etc.）.However,aforementioned fabrication technologies often suffer from complicated process,expensive equipment,time consuming,etc.,which substantially restricts their wide applications.Therefore,it is still a huge challenge to fabricate flexible pressure sensor coupled with outstanding performances through a facile but cost-efficient method.In this paper,with the help of hot-air-gun,TPU film and SWCNTs/TPU composite film with quasi-hemispherical micropatterned array have been successfully prepared.Subsequently,TPU film and SWCNTs/TPU composite film with quasi-hemispherical micropatterned array were used as the dielectric layer of capacitive response sensor and flexible electrode of resistance response sensor,respectively.Finally,capacitive and piezoresistive flexible pressure sensors were fabricated based on the dielectric layer or flexible electrode pressure.The main research contents are as the follows:1.Preparation and application of capacitive flexible pressure sensor.TPU dielectric layer with micropatterned array was prepared by hot-air-gun.A capacitive flexible pressure sensor was fabricated by assembling aluminum foil electrode and TPU dielectric layer with micropattern.The results suggested that the capacitive flexible pressure sensor high sensitivity(0.008 k Pa^-1),wide measure range（0～170 k Pa）as well as excellent durability over 5000 loading/unloading cycles.The capacitive flexible pressure sensor can be used to measure finger curvature and finger pressing.2.Preparation and application of piezoresistive flexible pressure sensor.In this paper,with the help of hot-air-gun,SWCNTs/TPU composite film with quasi-hemispherical micropatterned array have been successfully prepared.They are further assembled into the interlocked flexible pressure sensor,exhibiting fast response time（<46 ms）and a wide pressure monitoring range（0.055～254.8 k Pa）as well as excellent durability over 20000 loading/unloading cycles.Interestingly,the interlocked flexible pressure sensor exhibits multifunction to simultaneously discriminate pressure-temperature stimuli.Moreover,it can monitor a variety of human physiological signals（e.g.,arterial pulse waveform,voice recognition and human breathing behavior）,indicating a promising application in human-machine interaction.Furthermore,the as-prepared interlocked flexible pressure sensor could be connected to a wireless transmitter for wireless monitoring respiratory rates.Considering the facile preparation process and the low-cost raw materials,this approach can be easily scaled up for practical production.