Study On The Properties Of Self-assembled Aluminum-based Superamphiphobic Surfaces Of Perfluoroalkyl Phosphates

In recent years,researches on superhydrophobic surfaces has attracted extensive attention and been deeply studied.In order to expand the application fields of the surfaces,researchers have made great efforts to design the surfaces with both superhydrophobic and superoleophobic properties.In general,the typical two strategies are needed to achieve superamphiphobicity,i.e.(1)constructing micro/nanoscale hierarchical surface structures and(2)modifying the structured surfaces with low free energy chemicals.At present,according to the existing methods,superamphiphobic surfaces people have been prepared successfully.However,many of these methods usually require special equipment or complex technological process.In order to reduce the cost of preparation,in this paper,taking the ordinary industrial pure aluminum sheet as the matrix,based on the two steps of chemical etching and hot water bathing,the micro/nano structure was constructed.Stable superamphiphobic Al surfaces were achieved by derivitization with self-assembly monolayers of fluoride alkylphosphoric acid.Field emission scanning Electron Microscopy(SEM),Energy Dispersive Spectrometer(EDS),X-ray diffractometer(XRD),Fourier transform infrared spectrometer(FTIR spectrometer),-X-ray photoelectron spectrometer(XPS)and Contact angle measuring instrument were used to study the superamphiphobic surfaces.The composition and wettability were analyzed.The main works of this paper are as follows:(1)By adjusting the treating time of copper chloride etching and 90 ? hot water bathing,the micro / nano composite structure of pure aluminum surfaces were controlled.Proper self-assembly time of fluorinated alkylphosphoric acid was found.The superamphiphobic Al surfaces and liquid droplets are in Cassie state.The optimum value of static water contact angle is 170°,and the hysteresis is 2°.Meanwhile,the static contact angle of peanut oil is 156°,and the hysteresis is 4°(2)The durability tests showed that the surface micro-mechanism of superamphiphobic aluminum is destroyed after sand flushing,and the solid-liquid contact state transformed from Cassie to wenzel,which is mainly reflected in the enhanced adhesion between the surface and the liquid.Through the electrochemical corrosion of NaCl solution,it is found that the corrosion resistance of aluminum surface is improved because the superamphiphobic surfaces are in Cassie state,and the self-assembled monolayer and the air layer in the rough structure gap alleviate the corrosion process.The results of heating experiment showed that the superamphiphobic properties of aluminum surface can be kept stable below 300 ?.(3)The smooth aluminum surface was constructed by magnetron sputtering,and the self-assembly process of fluorinated alkyl phosphoric acid on aluminum surface after water bathing was studied.It was resulted that the-AlOOH species exist on the activated surfaces after water bathing.The organic molecules bind to the activated aluminum surfaces in the form of P-O-Al bonds.