Preparation Of Super-wetting Flexible Triboelectric Materials And Construction Of Portable Sensing Devices

The use of mine flexible sensors can monitor the physiological parameters of miners in real time for many consecutive days,which provides a basis for systematically recording various indicators among users.At present,most flexible sensors are single function and cannot adapt to some extreme environments,especially liquid environments such as dampness and sweat.Despite the enormous progress of flexible sensors in reducing power consumption,the supply and consumption of energy still limit the continued development of such devices.In this paper,we prepared environment resistant flexible conductive sensing materials to improve the environmental stability of flexible sensing devices by adjusting the interfacial wettability.Through the interface design,porous structure,micro cilia structure and porous/micro cilia composite structure were introduced on the surface of the friction layer to endow the device with great flexibility and sensitivity.On the basis of the research of sensor unit devices,a flexible multifunctional sensing system with an efficient energy supply platform was constructed to function electricity by incorporating friction technology.The main results are as follows:（1）Aiming at the stability of flexible wearable electronics in wet water and high temperature environments,a super-amphiphobic,flame-retardant smart sensing coating was constructed on the surface of cellulose cotton fabric by a multilayer deposition method.On this basis,a new all-weather conductive fabric（ACF）and a fire warning sensor（AFWS）were developed.The as-prepared ACF exhibited a high electrical conductivity of 1.1Ω/sq and excellent electrical stability even in harsh environments such as aqueous phase,oil phase,corrosive liquid,and flame.Meanwhile,the developed ACF works well even after 30%stretching and 1000 bending deformations.Benefiting from the fast reconstruction of the conductive network at high temperature,the as-prepared AFWS exhibits extremely fast response time（3 s）for flame and high temperature detection.Furthermore,a high-temperature sensing mechanism was proposed based on the reconstruction of the conductive network during ambient temperature rise.All these attractive advantages show great application potential in large-area fabrication of wearable electronic textiles,real-time health monitoring,and fire warning.（2）Aiming at the challenge of energy supply for flexible wearable sensing devices,a triboelectric nanogenerator（PFL@WFCF-TENG）composed of a superhydrophobic porous flexible layer（PFL）and a waterproof flexible conductive fabric（WFCF）was fabricated by sacrificial template method and multilayer chemical deposition method.The designed PFL triboelectric layer and functional conductive fabric significantly enhance the output performance and stability of PFL@WFCF-TENG,including high output voltage（135 V）,high output power（631.5 mW/m²）and more than 15000 cycles work.The device is expected to power a variety of low-power electronics through mechanical motion.As a tactile sensor,PFL@WFCF-TENG still exhibits good linear sensitivity under various external conditions such as tensile strain,humid environment,and sweat.The designed portable haptic controller can precisely control a variety of electronic peripheral devices,and realize practical applications in the field of self-powered haptic sensing and human-computer interaction.（3）Aiming at the sensing range,electrical output characteristics,and biocompatibility of triboelectric sensing devices,a novel waterproof hybrid-dielectric-based TENG（HD-TENG）was fabricated by a simple two-step spraying process.The designed HD-TENG consists of a superhydrophobic hybrid dielectric layer（HDL）,an indium tin oxide（ITO）electrode,and a pure polydimethylsiloxane（PDMS）film on the bottom.Since the superhydrophobic HDL film has an internal micro/nanopore structure and a hierarchical superhydrophobic microciliary structure of the epidermis,this greatly improves the specific surface area and compressibility of the entire device.Through structural optimization,HD-TENG exhibits high flexibility,excellent washability and moisture resistance.In single-electrode mode,the HD-TENG with an effective area of 5 × 5 cm² exhibits high output performance with an open-circuit voltage(V_oc)of 465 V,a short-circuit current(I_sc)of 60 μA,and a maximum power density of 3.2 W/m².As a wearable sensor,HD-TENG can not only be used as a pressure sensor to monitor various external pressures,but also identify the type of objects according to the voltage generated when different external objects are touched.It can also be used as a motion sensor to realize self-powered motion monitoring while harvesting various human motion energy.（4）Aiming at the influence of the interfacial shielding effect of triboelectric sensing devices at the water-containing interface,a new type of hydrovoltaic electricity generator（HEG）was fabricated by a simple two-step spraying process using magnetic field assistance.The designed HEG consists of a top metal electrode,a middle superhydrophobic microciliary film（SMF）,and a bottom ITO electrode.This upgraded configuration enables the bulk effect between the top electrode,the inner ITO electrode,and the SMF to replace the traditional liquid-solid interface effect,thereby facilitating charge transfer.As a charge-inducing layer,the as-prepared SMF has excellent superhydrophobicity,transparency,and triboelectricity,which greatly improves the charge refresh efficiency on the device surface.The results show that the bulk-effect based HEG can obtain water droplet and wave energy in nature with good output efficiency,and output power can reach 215 mW/m² and 1.3 W/m²,respectively.As a water environment monitoring sensor,HEG can not only be used to monitor water movement,including water droplet drop frequency,drop height,water droplet size and water wave frequency,but also can be used for liquid composition identification in harsh environments.This water environment monitoring device has broad application prospects in some high-risk environments,especially in the monitoring of chemical leakage accidents that occur in laboratories and chemical plants.