Preparation And Properties Of Organic-Inorganic Hybrid Abrasion-Resistant Superhydrophobic Coatings

In recent years,inspired by"Lotus effect"and other superhydrophobic phenomena in nature,superhydrophobic surfaces which exhibit good excellent application performance in self-cleaning,oil–water separation,anticorrosion and anti-icing,have attracted much attention from researchers.However,the artificial superhydrophobic surfaces are often vulnerable to external force damages and lose superhydrophobicity due to their weak mechanical durability.In addition,the existed methods for preparing superhydrophobic coatings usually require complicated equipments and expensive chemical reagents.Thus it is of great significance to develop superhydrophobic coatings with low cost,simple preparation process,good practicality and strong mechanical durability.The main research contents of this study are summarized as follows:First,polydimethylsiloxane?PDMS?was synthesized by using hydroxy terminated polydimethylsiloxane?H-PDMS?and tetraethylorthosilicate?TEOS?as raw materials under the catalysis of dibutyltin dilaurate;Then ATP-P25/ER/PDMS superhydrophobic coatings were fabricated via a one-pot method by compounding PDMS with inorganic particles?attapulgite?ATP?and nano-TiO₂?P25??and epoxy resin?ER?.The effects of addition of ATP,mass ratio of ATP and P25,and the addition of ER on the hydrophobic properties and abrasion resistance of the coatings were studied.It was found that when the mass ratio of ATP to P25was 1.7?0.3,and the addition of ER was 14%of the mass of the solid filler,the prepared coating had good superhydrophobicity and abrasion resistance.Under this condition,the WCA and WSA of the coating were 152°and 6.7°,respectively.And the coating could maintain its superhydrophobicity after 280 cm of abrasion length under 100 g of weight.The surface morphology and chemical composition of the coating were characterized by SEM and FT-IR,respectively.The preparation mechanism of the superhydrophobic coating was discussed.It could be observed from the SEM images that the micro-nano rough structure constructed by P25 and ATP was favorable to the superhydrophobicity.And PDMS provided the low surface energy for the superhydrophobic coating.The hydrophobic properties of the coating did not change significantly after heat treatment at 300?for 12 h and irradiation by300 W UV light for 24 h,indicating good chemical durability.And the coating exhibited lower water adhesion performance and good self-cleaning property.The hydrophobic reagent stearic acid?SA?was used to modify ZnO particles to obtain stearic acid-modified hydrophobic ZnO?SA-ZnO?;while methyl polysiloxane?MPS?with three-dimensional network structure was produced by the hydrolysis and condensation of methyltriethoxysilane?MTES?.On the basis of this,a SA-Zn O/MPS/PDMS superhydrophobic coating was prepared by droplet-coating method,in which polydimethylsiloxane?PDMS,Sylgard-184?and curing agent were introduced.And MPS would bond SA-ZnO particles tightly onto substrates to enhance the mechanical durability of the coating,and PDMS could hinder the photocatalytic activity of ZnO particles,and improve the UV-durability of the hydrophobic coating.When the mass ratio of ZnO to SA was 2.8:0.35,and MTES to PDMS was 2.5:0.2,the prepared SA-ZnO/MPS/PDMS coating exhibited the superhydrophobicity with higher WCA?154.3°?and lower WSA?1.9°?.The mechanical durability of the coating was evaluated by the sandpaper abrasion test and the knife-scratch test.The coating still maintained good superhydrophobic properties after knife-scratch test and 320 cm of abrasion test.Furthermore,after irradiation by 300 W UV light for 24 h,WCA is still about 153.8°,WSA is about 2.8°.And the results of SEM and FT-IR showed that the rough surface structure and low surface energy supplied by the SA-ZnO particles were beneficial for the coating to capture air.The area fraction of air-liquid contact was 89%calculated from the Cassie-Baxter theoretical equation.And the SA-ZnO/MPS/PDMS superhydrophobic coating with good mechanical durability also showed easily physical repairability.When the superhydrophobic coating was damaged by strong acid and alkali,such as HCl aqueous solution?1 M?and NaOH aqueous?1 M?,it could recover its superhydrophobicity through simple sandpaper abrasion.The whole repair-damage process could be repeated for many times.And the coating exhibited good self-cleaning properties and temperature stability.