Functionalization of carbon nanotube carpets for wettability tailoring

LM. He, A. Karumuri and S.M. Mukhopadhyay
Wright State University,
United States

Keywords: nanotube arrays, hydrophobic, hydrophilic, surface modification, plasma treatment

Summary:

Controlled arrays of carbon nanotube (CNT) arrays on solids can provide very strong enhancement of several surface related properties. For selected applications where the CNT should interact with a liquid, wettability of CNT arrays may be desirable. Pure aligned CNT carpets are super-hydrophobic, and short-term microwave plasma was used to make it hydrophilic (decreasing its contact angle with water). Contact angles could be tuned by controlling the exposure time and microwave power. Moreover, the hydrophilic behavior could be reversed with thermal treatment, making this a very effective approach of creating structures with tunable and reversible wettability. Surface morphology was studied using scanning electron microscopy (SEM) and chemical states were analyzed by x-ray photoelectron spectroscopy (XPS). A contact angle model based on Young, Wenzel and Cassie regimes has been used to explain some of these effects.