Superhydrophobic and Low Reflectance Carbon Nanotubes Buckypapers

Abstract

In this paper, carbon nanotube (CNT) buckypapers (BPs) were produced by vacuum filtration of CNT water suspensions prepared by sonication using 0.5 wt % of Triton X-100 dispersing agent. The as-produced BPs were efficiently dispersed and presented very low optical reflectance, with an average reflectance of 1.30% in the visible range and hydrophilic/oleophilic properties, readily absorbing water or oil liquid drops through their network of pores. Plasma treatment with 1, 1, 1, 2 tetrafluoroethane (C 2 H 2 F 4 ) turned the BPs superhydrophobic with water contact angles (CA) greater than 140°, while still maintaining their oleophilic properties unchanged. This effect is attributed to the combination of the decrease of surface energy and modification of the surface structure with micro/ nanopores due to the coating with a fluorocarbon film. After only 1 minute plasma treatment, the BPs presented high hydrophobicity (CA = 145°) while keeping their oleophilicity and the very low optical reflectance essentially unaffected. These results indicate that a good combination of low reflectance and a superhydrophobic/oleophilic behavior can be achieved which is of importance for technological applications that require super black surfaces and prevent water from being absorbed, improving the handling of optical signals and increasing the useful life of materials.

Post-Consumer Polyurethane Foams Hydrophobization Through Surface Modifications for Oil Spill Sorption

“…For the S46 lubricating oil, Un-N presented an angle of 77.3° and Un-PC 82.2°, while for seawater the angles were 90.1° and 104.4°, respectively. This suggests that both new and post-consumer unmodified foam should be poorly attracted to oil but too attractive to seawater since the closer to 180°, the lower the seawater sorption and the closer to 0°, the greater the oil sorption 18 . All modified foams in contact with lubricant oil showed a contact angle of 0° after 5 s, which means that all the oil deposited on the foam surface was sorbed due to the success in increasing the oil affinity.…”