Nanostructured metal surfaces and their passivation for superhydrophobic and anti-icing applications =

Abstract

In cold regions, ice accretion on the power transmission lines can cause several undesirable mechanical or electrical events often leading to power failures. A natural phenomenon, called superhydrophobicity or “Lotus Effect”, seems to be promising to develop surface modification techniques suitable to eliminate pollution from the power lines and to reduce the ice adhesion effectively. The aim of this project is to mimic the lotus effect on conducting surfaces, using metallic nanostructures and then passivating them with low surface energy coatings, to achieve materials with low bonding affinity to water and ice, with a view to ultimately preventing ice accumulation on electricity network parts. Attempts have been made to study the superhydrophobicity of copper surfaces covered with silver structures, made by galvanic exchange reaction and passivated with stearic acid. A water contact angle of higher than 156o with a contact angle hysteresis lower than 4o has been obtained. Also, superhydrophobic copper surfaces have been prepared by coating them with previously made silver nanoparticles in colloidal solution, after passivating with plasmapolymerized Teflon and comparable contact angles have been found. Results of optimization of chemical processes and coating methods, the essential parts of this research, will be discussed.