Preparation And Properties Study Of The Superhydrophobic Surfaces With Controlled Adhesion By Benzoxazine

Wettability and wetting state are two important properties of the solid surface.In recent years,researchers inspired by superhydrophobic phenomena such as lotus leaves and red rose petals in nature have prepared a large number of biomimetic superhydrophobic surface materials and successfully applied them to self-cleaning,no loss transfer of microdroplets,oil-water separation and other fields.Superhydrophobic surfaces have been widely studied and can now be obtained by a variety of materials and methods,but most preparation methods of superhydrophobic surface have disadvantages of high cost,complicated process,environmental pollution,and instability,which seriously impede the application of superhydrophobic surface materials in the actual industry.Whether the solid surface properties are related to their bulk phase composition and growth environment,and whether the superhydrophobic surface materials with controlled adhesion can be prepared by regulating the bulk phase composition and growth environment,these important issues have not attracted the attention of researchers.In view of the above problems,the research topic was based on benzoxazine as the matrix resin,utilized different metal chlorides to regulate the bulk phase compositions of the matrix and selected different curing medias to control the solid surface growth environments.The hydrophobicity and adhesion to water were evaluated by contact angle and sliding angle of water on the surface of the new synthetic materials named Metal chlorides-polybenzoxazine?M-PBZ?.The effects of loading substrate,volume ratio of solvent methanol and phase separation agent toluene,aging time,the type and mass percentage of metal chlorides,curing temperature,curing time and curing medium on the hydrophobicity and adhesion to water of synthetic materials were investigated.The surface morphology,chemical composition and performance of M-PBZ superhydrophobic surface were characterized by modern scientific analysis instruments.The relationships between surface chemical composition and performance were studied,and the effects of bulk phase composition and growth environment on surface wettability and wetting state were also analyzed.Moreover,the formation mechanism of M-PBZ superhydrophobic surface and the adhesion control mechanism were both explored.The simulation application of no loss transfer of microdroplets on the high adhesion superhydrophobic surface and the self-cleaning performance of low adhesion superhydrophobic surface were also investigated.The results showed that the Sn-PBZ superhydrophobic surface with a contact angle of up to 154.2°can be successfully prepared under the follow conditions,aluminum plate as the surface of the load substrate,volume ratio of methanol to toluene 1:2,aging time 11 h,mass percentage of SnCl₄·5H₂O/benzoxazine 18.75%,curing temperature 200°C,and curing time 2 h.Superhydrophobic surface of M-PBZ with controlled adhesion can be synthesized in situ in one step by controlling the bulk phase composition and surface growth environment of polybenzoxazine.It has been found for the first time that the wettability and wetting state of the superhydrophobic surface of M-PBZ with controlled adhesion strongly depended on its bulk phase composition and growth environment.Moreover,this in situ synthesized superhydrophobic surface with controlled adhesion had very high stability.The formation mechanism of M-PBZ superhydrophobic surface was that under the induction of metal cations and toluene,benzoxazine monomers formed micelle-like structures by molecular self-assembly,cured in non-polar curing medium,these micelle-like structures retained and connected to each other by covalent bonds to form micro–nanoscale hierarchical rough structures,and finally obtained the superhydrophobic surface of M-PBZ.Analysis of the adhesion of water to superhydrophobic surface showed that the high adhesion superhydrophobic surface of M-PBZ belonged to the"petal"state,while the low adhesion superhydrophobic surface of M-PBZ belonged to the"lotus"state.The prepared M-PBZ superhydrophobic surface can be applied to no loss transfer of microdroplets and self-cleaning.The research of this subject not only injects new ideas for the study of superhydrophobic surface materials with controlled adhesion,but also provides useful enlightenment for the preparation of heterogeneous catalysts and drag reducing materials.