Based On Organic-Inorganic Nanoparticle Composite Construction Of Wood Superhydrophobic Surface And Performance Study

Wood is a porous structure rich in hydroxyl groups and other hydrophilic groups,which is highly susceptible to water absorption and deformation,microbial and fungal growth,which seriously affects its use.Superhydrophobic modification of wood surface can make wood water repellent,chemically resistant and self-cleaning,thus it is of great practical importance to broaden the range of wood applications.In this study,based on the bionic principle of"lotus leaf effect",a fluorine-free chemical reagent was chosen to combine organic and inorganic nanoparticles in a simple and mild way to design and construct a solid micro-nanostructure on the wood surface,and after low surface energy treatment,a superhydrophobic wood with mechanical stability,chemical durability,and self-cleaning properties was obtained.The superhydrophobic wood with mechanical stability,chemical durability,and self-cleaning properties was obtained by low surface energy treatment.The main research contents and results are as follows:（1）Construction of hydrophobic surface of wood based on TA-Fe^III reduced Ag ions and its performance studyThe hydrophobic wood was prepared by using TA-Fe^Шcomposite coating formed by coordination of organic compound tannic acid（TA）with inorganic trivalent iron ion(Fe³⁺),in situ reduction of Ag⁺to Ag nanoparticles loaded on the wood surface by using the adhesion of the composite coating and the good reduction ability of free catechol in TA,and grafting hydrophobic long chains on the composite coating by low surface energy treatment.The results showed that with the increase of the number of self-assembly and the deposition of the reduced Ag nanoparticles on the wood composite coating,it led to the development of a moderate rough structure on the wood surface.The contact angle on the unmodified wood surface was 52.0°,which decreased rapidly with increasing contact time,and water droplets penetrated into the wood quickly.In contrast,the contact angle of the modified wood increased from 138.2°to 143.7°for the TA-Fe^III/wood specimen and from 142.3°to146.7°for the TA-Fe^III/Ag/wood specimen as the number of self-assembly increased,giving the wood excellent hydrophobic properties.The contact angles of the hydrophobic wood were higher than 135.0°under severe conditions such as strong acid,strong alkali,organic solvent,ultrasonic shock and UV irradiation,and the prepared hydrophobic wood exhibited excellent environmental stability and chemical durability.（2）Construction of a superhydrophobic surface for wood based on the adhesion of polydopamine and its performance studyFirstly,a polydopamine coating was deposited on the wood surface by dopamine oxidative autopolymerization,and 3-aminopropyltriethoxysilane（silane coupling agent KH550）and ethylene glycol diglycidyl ether（EDGE）were added,and KH550 could improve the dispersion of TiO₂ and graft amino functional groups on its surface,and the amino groups on the polydopamine coating or KH550 and the epoxy groups in the cross-linking agent EDGE underwent The ring-opening reaction of poly（dopamine）coating or KH550 with the epoxy group in cross-linker EDGE firmly fixes the nano-TiO₂ on the surface of wood,and then the superhydrophobic wood is prepared by low surface energy treatment with octadecyltrichlorosilane（OTS）.When the added nano-TiO₂ concentration was2%,the static contact angle of the PDA/KH550/TiO₂/EDGE/OTS wood surface reached 156.5°and the rolling angle was 6.9°,and the wood superhydrophobic surface was successfully constructed.The prepared wood superhydrophobic surface still has excellent hydrophobic properties after the tests of strong acid and strong alkali solution immersion and ultrasonic shock,indicating that the prepared wood superhydrophobic surface has excellent chemical resistance and stability.（3）Construction of PDMS/TiO₂ superhydrophobic film on wood surface and its performance studyPolydimethylsiloxane（PDMS）with stable physicochemical properties and hydrophobic properties and TiO₂ nanoparticles were selected to be blended,and PDMS would physically coat TiO₂nanoparticles and thus hydrophobically modified.The mixed solution is then sprayed on the wood surface by one-step spraying method,thus a superhydrophobic film of organic matter-inorganic nanoparticles composite is prepared on the wood surface to realize the superhydrophobic modification of the wood surface.The surface morphology and microstructure of the composite films were adjusted by changing the mass ratio of PDMS and TiO₂ nanoparticles to change the surface roughness and wettability of the wood.The results show that when the mass ratio of PDMS to TiO₂ is 4﹕4,the superhydrophobic wood surface has the best hydrophobic effect with a contact angle of 165.2°and a rolling angle lower than 10.0°;the modified wood not only has good hydrophobic properties but also has excellent self-cleaning properties.The results of sandpaper rubbing and outdoor weathering experiments also proved that the PDMS/TiO₂ composite superhydrophobic film on wood surface has good mechanical stability and environmental durability.The prepared superhydrophobic wood retains its superhydrophobic properties and has good chemical resistance after impregnation with strong acids and alkalis.