A Green Process to Prepare Hydrophobic and Transparent CNT-Based Surface

Abstract

A green process to prepare the hydrophobic and transparent CNT-based surface was developed without using any toxic chemicals, solvents or gases. CNT brush (CNT-b) powder, which was prepared by the repeated CVD, was the main material to prepare the desired surface. An adhesive layer of ethyl cellulose (EC) was spin coated on the glass substrate, where EC formed a networked porous microstructure. A low concentration CNT-b suspension was obtained by sonication of the mixture of CNT-b powders, sodium dodecylbenzenesulfonate (SDBS) and deionized water. To obtain the stabilized CNT-b suspension, it was found that 40 min of sonication time and SDBS/CNT-b weight ratio being 0.1 were required. The target surface was then prepared by spin coating CNT-b suspension on the EC coated glass. The contact angle of the prepared surface was around 120o and the optical transmittance was around 93% for the visible light. Either increasing the number of spin coatings or increasing the concentration of CNT-b suspension could slightly increase the contact angle to around 130o but the optical transmittance significantly reduce to about 75%, leading to a semi-transparent sample.