Study On Interface Structure Design And Properties Of Organic-inorganic Hybrid Conductive Composites

With the development of information technology,wearable electronic devices and some intelligent electronics have received the widespread attention.However,current smart electronic devices usually only have a single performance,and cannot adapt to multiple functional requirements in a complex environment.By introducing the inorganic conductive filler into the polymer matrix,the advantages of each component can be combined effectively,so as to create the conductive polymer composites with not only good processing properties,but also a variety of functions.At present,how to exploit the various properties of conductive composites,improve the various properties of composites and realize the high integration of various properties are the focus of research.In this paper,several new multifunctional organic-inorganic hybrid conductive composites have been developed with the aim of designing the interface structure and studying the properties of conductive polymer composites.Firstly,a conductive PVDF/CI/MXene film which can detect strain and shield electromagnetic radiation is developed.Based on the sensing and electromagnetic shielding performance,it is expected to be used as a wearable electronic device to monitor and protect the human body.In order to meet the requirements of the wearable device,the non-woven fabric is assembled with PVDF/Ag NWs/CNTs.The wearable fabric not only has human monitoring and protection properties,but also is softer and more comfortable compared to the thin film.Then,PVDF/MXene/PI sandwich conductive film was developed.The composite material can not only be used to monitor and protect the human body,but also has the electric heating property,which can be used for thermal treatment of human body.To develop other properties of conductive composites,PTFE/MXene/PI composite material was developed.The composite material possess both electromagnetic shielding and electro-thermal driving properties.Taking intelligent shielding curtain as an example,it can be used as an intelligent electronic device,which adapts to the development of the intelligent era.Finally,in order to improve the external impact resistance of the conductive composite material,the PBS/MXene sponge composite was developed.The introduction of PBS successfully gave the composites excellent ability to resist external impact.The specific research contents and results are as follows:1.Development of PVDF/CI/MXene magnetic conductive composite film and its sensing and electromagnetic shielding performance.The solution casting method was used to prepare PVDF/CI film and PVDF/CI/MXene conductive film was obtained by further spraying MXene nanosheets.Based on the piezoelectricity of polyvinylidene fluoride(PVDF)and magnetism of carbonyl iron(CI)particles,the composite film exhibited dual stimulus-response properties to the external strain and magnetic field.The introduction of conductive MXene endows PVDF/CI/MXene composite films with excellent conductivity,which can effectively shield the electromagnetic radiation from the outside world.Finally,based on the sensing performance and electronic shielding performance of the conductive composite film,it is expected to be used as a wearable electronic device to monitor the movement of the human body and protect the human body from electromagnetic radiation.2.Development of PVDF/Ag NWs/CNTs fabric sensor and its performance of human body monitoring and electromagnetic shielding.Firstly,silver nanowire(Ag NWs)and carbon nanotubes(CNTs)were coated on the non-woven fabric by dropping and drying method,and then PVDF solution was cast on the fabric to obtain PVDF/Ag NWs/CNTs multifunctional conductive fabric.The introduction of the non-woven fabric improved the softness and comfort,which make the conductive composite meet the development requirements of wearable devices.The double conductive network of Ag NWs and CNTs improves the electrical conductivity of the non-woven fabric,which makes the composites exhibit excellent electromagnetic shielding performance with the maximum shielding value up to 34 dB.In addition,the excellent mechanical properties of CNTs also help to improve the mechanical strength of the non-woven fabric.Moreover,the sensor possesses a force-sensing property by generating different piezoelectric voltages(0,0.4,1.0,and 1.5 V)when stimulated by various forces(0,20,44,and 60 N).Finally,not only can it respond to different external stress in a timely manner(response sensitivity of?0.024 V/N,response time of?35 ms),but it can also monitor different body movements,such as joint bending,running,and jumping.3.Preparation of PVDF/MXene/PI sandwich conductive composite film and its human thermal management,monitoring and electromagnetic shielding performance.The conductive MXene was sprayed on the PVDF surface by solution spraying method,and then polyimide(PI)tape was pasted to assemble the PVDF/MXene/PI sandwich type conductive composite film.The shielding ability of the composite to electromagnetic radiation was improved by controlling the spraying amount of MXene.The influence of external strain on the intermediate MXene conductive network gives the composite film excellent and sensitive human monitoring function,which can monitor finger bending,arm bending,speaking,drinking,touching and pressing.Finally,according to the Joule heat,PVDF/MXene/PI composite film can generate heat under the loading of electric stimulus.The adhesion of high-temperature insulating PI tape effectively avoids the direct contact between the conductive layer and the human body,and make PVDF/MXene/PI composite film can be used for thermotherapy of the human body.4.Development of PTFE/MXene/PI conductive sandwich structure and its electro-thermal actuation and electromagnetic shielding performance.A flexible,PTFE/MXene/PI conductive sandwich structure is constructed through a very simple and fast "cutting and sticking" method by taping polytetrafluoroethylene(PTFE)and PI tapes onto the surface of MXene film.The commercially available PTFE and PI tapes endow PTFE/MXene/PI sandwich structure with ideal mechanically robustness and hydrophobic self-cleaning function,thus it can work in different environments.Remarkably,PTFE/MXene/PI sandwich structure shows an outstanding EMI shielding ability with the maximum SET value of 44 dB owing to the high electrical conductivity of MXene film.More importantly,the PTFE/MXene/PI sandwich actuator can bend from PTFE side toward PI side under the electrical stimulus,because the excellent electrothermal MXene layer is sandwiched between the two tapes with large difference in thermal expansion coefficients.At last,a smart shielding curtain with the combination of actuation properties and EMI shielding performance is finally developed as a principle of concept,which further indicates the multifunctional PTFE/MXene/PI ETA can be widely applied in smart EMI shielding system and soft robotic devices.5.Development of flexible and lightweight melamine sponge/MXene/polyborosiloxane(MSMP)hybrid structure for high performance electromagnetic interference shielding and anti-impact safe-guarding.To improve the mechanical anti-impact property of conductive composites,a lightweight and flexible Melamine Sponge/MXene/Polyborosiloxane(MSMP)hybrid structure is proposed by incorporating conductive Ti3C2TX and polyborosiloxane(PBS)into porous melamine sponge(MS).The nanocomposite shows outstanding energy dissipation ability which can efficaciously degrade the external impact force due to the shear stiffening characteristic.Meanwhile,the nanocomposite presents an excellent electromagnetic interference(EMI)shielding ability with a maximum SET value of 39 dB.Besides,the MSMP displays obvious adhesion property after being cut due to the viscoelastic property and internal supramolecular network of PBS,thus can repeatedly resist the external damage.Finally,a safety sports protective equipment is developed by integrating the MSMP nanocomposite into the common sportswear,which could provide bi-protection for human.Owing to the good integration of safe-guarding performance and EMI shielding properties,the MSMP nanocomposites show high prospective potential in precision electronic instruments and wearable protective equipment.