Ultrasound-assisted Preparation Of Superhydrophobic Materials And Application Of Oil-water Separation

In recent years,the application of superhydrophobic materials in oil-water separation has attracted wide attention.The study found that the super-hydrophobic material can effectively recover the oil phase and oil leakage in the oily wastewater,thereby reducing the waste of resources and protecting the ecological environment.At present,inspired by the phenomenon of biological adhesion of marine mussels,the technology of constructing superhydrophobic layered structure by using polydopamine coating greatly limits its practical application because of the long time consumed for self-polymerization of dopamine to polydopamine in weak alkaline environment.Therefore,how to quickly and efficiently realize dopamine polymerization to construct superhydrophobic materials for oil-water separation has become an urgent problem to be solved.In this paper,we use cheap and easily available commercial sponges and textiles as substrates to prepare superhydrophobic materials.The main contents include the following two aspects:(1)we propose an ultrasound-accelerated strategy to construct superhydrophobic hierarchical surfaces on various commercial porous sponges by simply immersing sponges into an alkaline solution of dopamine(DA)and dodecyltrimethoxysilane(DTMS)in the presence of ultrasound.Ultrasound irradiation can significantly accelerate the formation of hierarchical surface comprising of PDA and DTMS.As a result,the hierarchical superhydrophobic surfaces are obtained within 25 min.These superhydrophobic sponges not only can efficiently recover oil or organic solvents from oil-water mixture,but also has good physical,chemical and environmental stability.It also maintains high oil absorption efficiency and superhydrophobic performance after several cycles of oil absorption.This strategy proposes a rather high efficiency and time-saving process for constructing superhydrophobic hierarchical surf-aces,which may be useful for the rapid engineering of superhydrophobic surfaces.(2)Dopamine(DA)and octadecyltrimethoxysiloxane(ODTMS)were placed in alkaline water medium to form coating solution by ultrasound.After soaking the fabric in the above coating solution for 24 hours,polydopamine and low surface energy substances will deposit on the surface of the fabric,forming superhydrophobic fabric with contact angle as high as 157.8±2.4°.The coating is self-healable against acid/base etching and plasma damage.The prepared superhydrophobic fabric can be used as a sieve or oil absorbing material to separate the oil/water mixture,and the separation efficiency is above 90%.