Bio-inspired Assembly And Mechanisms Of Graphene-based Nanometer Material On The Bamboo Surface

The purpose of this study is to solve the problems from the bamboo industry including poor resistance to mould and rot fungi,poor dimensional stability and inflammable.It is the first time to build graphene-based nanomaterials on bamboo surface and to form new type functional bamboo composite materials.As a result of our expriments,several functional bamboo was made with hydrophobic performance,excellent dimensional stability,photocatalytic degradation,antibacterial and antifungal properties,conductive properties and flame retardant properties.Our research conclusion is helpful for the bamboo industry to improve the bamboo product and to produce new product with more added value,which is of great significance to the promotion of bamboo industry.Based on the bionic concept and inspired from the shell strcuture,a new type bamboo coated with graphene-based nanomaterials was made with a special structure like the shell.Bamboo,as the substrate in the bottom layer,firstly was coated with reduced graphene oxide nanosheet as the middle layer,and then was coated with nano structure matal materilas as the surface layer.A hydrothermal treatment method was used and ZnO?TiO₂?SiO₂?Ag were choose as the surface nanometal.The crystal phase,morphology,microstructure and other physicochemical properties of the as-prepared samples were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscope,energy-dispersive X-ray analysis,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy.Meanwhile the improved properties such as antibacterial,hydrophobic,dimensional stability,photocatalytic degradation,anti mildew,conductivity and flame retardant,were tested.The preparation mechanisms of several new multifunctional bamboo were discussed.The main research results and conclusions are as follows:?1?A novel and efficient process for fabrication of antifungal bamboo timber was reserched using reduced graphene oxide as coating materials.The reduced graphene oxide coating bamboo timber?RGOBT?was formed as the following mechanism,graphene oxdie was reduced to RGO nano plate in the hydrothermal process and self-assembly deposited on the bamboo surface via the adsorption and hydrogen bonding.The weight loss of RGOBT decreased 12.9% when caused by white rot fungi and decreased 34.5% when caused by brown rot fungi,which showed that corrosion resistance of RGOBT was significantly improved.?2?A new type bamboo timber?RGO@ZnOBT?coated with ruduced graphene oxide and nano crystal ZnO was fabricated by two steps combined with dip-dry and hydrothermal process.The Aspergillus niger mould resistance of RGO@ZnOBT is grade 2,and both the trichoderma virideduring and Penicillium citrinum mould resistance of RGO@ZnOBT are grade 0,according the China standards,which is better than the grade 4 of original bamboo timeber?BT?.The Escherichia coli resistance test showed that antibacterial circle of RGO@ZnOBT is 8mm,which is greatly higher than BT.The antibacterial and thermal stability is greatly significantly improved.?3?A new type bamboo timber?RGO@TiO₂BT?coated with ruduced graphene oxide and nano crystal TiO₂ was fabricated by two hydrothermal processes.The crystal phase,morphology,microstructure and other physicochemical properties of BT,RGOBT and RGO@TiO₂BT were characterized by X-ray diffraction,scanning electron microscopy,energy-dispersive X-ray analysis,and Fourier transform infrared spectroscopy.The GO dispersion and RGOBT-TiO₂ reaction solution were analyzed by transmission electron microscopy.The RGO@TiO₂BT composite posses excellent photocatalytic activity,and the removal rate of Rhodamine B,methylene blue and methyl orange after 60 min photodegradation were respectively 73.7%,80.7%and 88.4%,superior to the BT and RGOBT.Additionally,RGO@TiO₂BT exhibited improved thermal stability and fire-resistant properties with a limiting oxygen index of 33.2%.?4?A new type bamboo timber?RGO@SiO₂BT?coated with ruduced graphene oxide and nano crystal SiO₂ was fabricated by two hydrothermal process.SEM showed that the diameter of spherical SiO₂ nanoparticles is about 400 nm,with further FAS-17 coating treament,the as-prepared FAS-RGO@SiO₂BT has excellent hydrophobic property.The FAS-RGO@SiO₂BT,with a WCA more than 152°,have good hydrophobic obvious on tea,orange juice,milk,coffee green fruit juice,red wine and blue ink.With pH range from 1-14 of solution,FAS-RGO@SiO₂BT all showed higer hydrophobic obvious.After 90 d immersion test,the water weight of FAS-RGO@SiO₂BT is 9.7%,and the thickness of the expansion is 0.5%,which showed that the dimensional stability was greatly enhanced.?5?A new type bamboo timber?RGO@AgBT?coated with ruduced graphene oxide and nano crystal Ag was fabricated via a hydrothermal proces and a silver mirror reaction.The RGO@AgBT composite posses excellent photocatalytic activity,and the removal rate of Rhodamine B,methylene blue and methyl orange after 60 min photodegradation were respectively 77.6%,88.8%and 78.4%,superior to the BT and RGOBT.Also the RGO@AgBT has a good antibacterial effect on Escherichia coli and Staphylococcus aureus.Moreover,the RGO@AgBT has excellent flame retardant properties with the limiting oxygen index 30.5%,which showed extinguish spontaneous in air combustion process.More intersting is that RGO@AgBT has the electrical conducting properties.