Preparation And Flexible Sensing Properties Of Cellulose-based Composite Carbon Aerogel/Hydrogel

Today,with the development of science and technology,the intelligence and automation of equipment play an irreplaceable role in social production and people’s life.With the development of society and the improvement of people’s living standards,in the face of risks such as population aging and food health problems,electronic devices,especially high-performance micro-flexible devices,are becoming more and more important in the fields of medical diagnosis,human-computer interaction and real-time sports monitoring.The development of high-performance core component sensors is still an important problem in electronic devices,and people’s requirements for materials are getting higher and higher.Many traditional materials cannot meet the diversified needs of modern technology.More importantly,the shortage of resources and environmental problems are particularly prominent,so the modification and development of bio-based materials has become an important research direction for workers,which is of great significance to the construction of sustainable green technology.As the most abundant natural polymer polysaccharide on the earth,cellulose has great potential development value due to its huge advantages such as environmental protection,wide range of sources,and sustainable recycling.In this work,using coniferous wood pulp as raw material,after beating,oxidation,freeze-drying and carbonization processes,carbon aerogels with porosity,extremely low density and good conductivity were obtained,and a carbon aerogel was constructed based on this A wearable pressure sensor with good stability,fast response and reusability;based on carbon aerogel,a carbonized crepe paper and hydrogel with carbon aerogel as the conductive network and hydrogel coating material were designed Composite gel,the composite gel of carbonized crepe paper and hydrogel not only retains the excellent electrical conductivity of carbon airgel,but also endows it with the stretchable plasticity and toughness of hydrogel.At the same time,the physical and chemical properties,morphology and mechanical properties of carbon aerogels and hydrogels were characterized,and then the mechanical and electrical properties of sensors and various human sports applications were studied.In addition,the hydrogel self-healing Properties,adhesion and antibacterial properties were characterized.This article researches as follows:Using coniferous wood pulp as raw material,the cellulose fibers are divided into fibrils through dispersing and beating mechanical treatment,and nano-scale microfibrils are constructed on the surface,and then chemically treated with sodium periodate oxidation and tannic acid crosslinking Promote fiber network entanglement and chemical combination,strengthen fiber network interaction,and enhance mechanical strength.Then,the cellulose fiber suspension is freeze-dried to prepare airgel,and the carbon aerogel is prepared through certain carbonization process technology.Through infrared,X-ray diffraction,X-ray photoelectron spectroscopy,Raman and scanning electron microscopy,etc.The samples were characterized from structure and morphology.The results show that the obtained carbon airgel has good electrical conductivity(10S/m)and low density(16mg/cm~3),and the mechanical strength is 80% higher than that before the untreated one.The pressure sensor assembled with this sensing material has The response time is 45 ms,the recovery time is 35 ms,the sensitivity is 3.5kPa-1,and it has a good cycle stability of 3000 times.It has the ability to accurately recognize facial expressions,and the 5×5 sensor array formed can accurately identify the position and weight of objects.At the same time,it is also accurate in the temperature range of-60℃～60℃ and the humidity range of 23～75%HR.The linear response relationship confirmed the potential application value of carbon airgel sensors in monitoring human motion and multifunctionalization of sensors.Using softwood pulp as raw material,cellulose fiber suspension was prepared by dispersion,cellulose fiber aerogel was prepared by freeze-drying,and carbon aerogel was carbonized.At the same time,using polyvinyl alcohol,gelatin and glycerol as raw materials,the gel solution was prepared by 80 ℃ treatment,and the solution was cast in the mold with cut carbon aerogel in advance,and the carbon aerogel and hydrogel composite gel was prepared by repeated freeze-thaw method.The composite gel of carbon aerogel and hydrogel was analyzed by infrared,X-ray electron diffraction,X-ray photoelectron spectroscopy and frozen scanning electron microscope,in order to characterize the properties and morphology of the samples.The mechanical properties and sensing properties of carbon aerogel and hydrogel composite gel were characterized by texture instrument and digital source table.The results show that the composite gel of carbon aerogel and hydrogel has high tensile strength of 50 kPa,500% breaking length and excellent mechanical stability which can be repeated for 12500 times.As a strain sensing material,it has the response time of 87 ms,the recovery time of 87 ms and the strain coefficient of 3.5.it can make a rapid response to various movements of the human body,such as pronunciation,drinking water and limb movement,and has accurate recognition ability for frowning and smiling.It can work in the temperature range of-60 ℃ ～ 60 ℃.the composite gel of carbonized wrinkle paper and hydrogel still maintains stable sensing performance and plasticity even if stored at room temperature for 7 days.Using the crepe paper composed of cellulose fiber as raw material,carbonized crepe paper was prepared after carbonization and used as electronic conductive network,polyvinyl alcohol and metal ion crosslinking and polyacrylic acid synthesized in situ were used as hydrogel polymer network to prepare conductive hydrogel.Carbonized crepe paper was coated in hydrogel with conductive hydrogel as coating material.A kind of carbonized crepe paper and hydrogel composite gel with good self-healing,antibacterial,adhesion and sensing properties was constructed.The composite gel made from carbonized crep paper and hydrogel based sensor of carbonized crepe paper and hydrogel has a fast response of 90 ms,and the strain coefficient is as high as 114.it still has good mechanical and sensing properties even under cyclic loading and unloading for more than5000 times.The composite gel made from carbonized crep paper and hydrogel has strong self-healing properties,including 50 ms conductive self-healing properties and mechanical self-healing properties for 15 h.Meanwhile,it has strong inhibitory effect on Escherichia coli and Staphylococcus aureus.Meanwhile,it has strong inhibitory effect on Escherichia coli and Staphylococcus aureus.It also has antibacterial activity against Escherichia coli and Staphylococcus aureus.