Preparation And Properties Of Fluorocarbon/Silica Composite Superhydrophobic Coating

Superhydrophobic materials have attracted much attention in marine anticorrosion and antifouling,automobile,construction and other industries because of their excellent properties,such as self-cleaning,waterproof,anti-fogging,anti-corrosion and so on.However,although there are endless reports on superhydrophobic materials,so far,there are no superhydrophobic materials really used in commercial production,because the superhydrophobic materials prepared by the current technology are not only expensive and complicated,but also the durability,weather resistance and other properties are not satisfactory.The purpose of this paper is to prepare superhydrophobic coatings with low cost and simple preparation process.Superhydrophobic coatings were prepared with 3X fluorocarbon resin as matrix material and silica(SiO2)as surface roughness material under the action of curing agent and various coating auxiliaries.Firstly,SiO2 particles were prepared by stober method using tetraethyl orthosilicate(TEOS)as silicon source and ammonia as catalyst.The effects of the amount of TEOS and ammonia on the micro-morphology and particle size of SiO2 were discussed respectively.The test and analysis shows that with the increase of the amount of TEOS,the particle size of SiO2 increases at first and then tends to be stable,and when the volume percentage of TEOS is 5%;the particle size reaches the maximum,which is 213 nm.The lipophilic degree of SiO2 increased at first and then decreased with the amount of TEOS,and the lipophilic degree in butyl acetate was higher than that in xylene.With the increase of the amount of ammonia,the particle size and lipophilic degree of SiO2 gradually increased,and the smoothness and regularity of SiO2 particles became better and better.Secondly,the nano-sized SiO2 was modified with silane coupling agents(KH-550,KH-560,KH-570,HMDS),and the modified nano-SiO2 was characterized.FT-IR results showed that the four silane coupling agents were successfully grafted onto the surface of nano-SiO2 without changing the structure of nano-SiO2.SEM and lipophilic degree analysis showed that the dispersibility of nano-SiO2,modified nano-SiO2 was improved compared with that of unmodified nano-SiO2.In terms of all aspects of properties,the modification effect of KH-550 is the best,KH-570 is the second,and HMDS is the worst.Finally,using the prepared and modified SiO2 as reinforcing fillers,the FEVE/prepared SiO2 composite coating andFEVE/modified nano-SiO2 composite coating were prepared,and the water drop contact angle(WCA),hardness,impact resistance and adhesion of the coating were characterized.The results show that the properties of the coating are improved to some extent after adding SiO2.In order to further improve the WCA of the composite coating,dimethyl silicone oil(PDMS)was dripped on the surface of the composite coating,according to the measurement of contact angle,it is found that the increase of WCA by PDMS is 7°?13°,and the highest contact angle is 112°.