Fabrication And Properties Of Micro/Nano Structure Based On Superhydrophobic Na-Mg-Al-Si Glass-ceramic Surface

Constructing rough surface and low surface energy modification is the main preparation method of superhydrophobic surface.However,the current preparation methods of superhydrophobic surfaces are mostly time-consuming,involving expensive instruments and equipment,tedious experimental procedures,poor durability,and the rough surface that is easily damaged,which makes it difficult to be used on a large scale in real life.Herein we fabricated a durable superhydrophobic surface by using crystals in glass-ceramic to construct fine three-dimensional micro-nano structures and low surface energy modification.In this paper,we find that the choice of the nucleating agent has a great influence on the morphology of the crystal,and then affects the size of the wettability.We used Cr₂O₃as the nucleating agent and nepheline as the glass-ceramic system to construct a three-dimensional flower-like micro-cluster structure.Differential thermal analysis（DTA）,X-ray diffraction（XRD）,scanning electron microscope（SEM）,laser scanning confocal microscope（CLSM）,X-ray photoelectron spectroscopy（XPS）,and contact angle test were used to characterize the sample structure and performance.The effects of different Cr₂O₃contents on the surface structure and wettability of the glass-ceramic were studied.The effects of different heat treatment processes and corrosion conditions on the surface roughness and wettability of the glass-ceramic were also studied.Determine the best heat treatment process and corrosion conditions.Finally,various performance tests were performed on the superhydrophobic glass-ceramic surface.The results show that the best sample processing conditions:the content of doped Cr₂O₃is 2.50%,the heat treatment conditions are 680℃nucleation for 4 h,790℃crystallization for 4 h,hydrofluoric acid corrosion concentration and time are 5 vol.%and30 s,respectively.The average roughness（Ra）of the surface obtained by processing the samples under this condition was 2.418μm,and the root mean square roughness（Rq）was2.810μm.After FAS-17 grafting,the water contact angle can reach 170.3±0.1°,and the sliding angle is about 2°.The surface structure of glass-ceramic is composed of continuous flower-like micro-clusters,and the length is 2-15μm.A large number of flower-like structures are self-assembled to form flower-like micro-clusters,and the flower-like structure is self-assembled from a large number of nepheline and forsterite nanocrystal pieces.The length of the nano-pieces is 0.1-3μm and the width is 50-900 nm.This special micro/nano structure can capture up to 98%of air to reduce the solid-liquid contact area and absorb a large number of low surface energy groups to reduce the surface energy,so that the surface reaches a superhydrophobic state.The formation of flower-like structure is that Cr₂O₃promotes the precipitation of nucleus of Mg Al Cr O₄spinel phase with octahedral structure.The octahedral nuclei provided more surfaces for the growth of nepheline and forsterite,resulting in the vertical growth of nepheline and forsterite along the eight outer surfaces of octahedron to form a three-dimensional flower-like crystal structure.The sample surface has excellent self-cleaning performance and resistance to strong acids and bases.The WCA is still as high as 165°after soaking in a strong acid and base solution for 48 h.In addition,the sample surface passed the 4H pencil hardness scratch test,which has excellent mechanical durability.The surface still has a WCA of167°after several tape peeling tests.