title: Effect of airborne contaminants on the wettability of supported graphene and graphite.
abstract: It is generally accepted that supported graphene is hydrophobic and that its water contact angle is similar to that of graphite. Here, we show that the water contact angles of freshly prepared supported graphene and graphite surfaces increase when they are exposed to ambient air. By using infrared spectroscopy and X-ray photoelectron spectroscopy we demonstrate that airborne hydrocarbons adsorb on graphitic surfaces, and that a concurrent decrease in the water contact angle occurs when these contaminants are partially removed by both thermal annealing and controlled ultraviolet-O3 treatment. Our findings indicate that graphitic surfaces are more hydrophilic than previously believed, and suggest that previously reported data on the wettability of graphitic surfaces may have been affected by unintentional hydrocarbon contamination from ambient air.
authors.affiliation: 1] Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA [2].
authors.forename: Zhiting
authors.initials: Z
authors.lastname: Li
authors.forename: Yongjin
authors.initials: Y
authors.lastname: Wang
authors.forename: Andrew
authors.initials: A
authors.lastname: Kozbial
authors.forename: Ganesh
authors.initials: G
authors.lastname: Shenoy
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Rebecca
authors.initials: R
authors.lastname: McGinley
authors.forename: Patrick
authors.initials: P
authors.lastname: Ireland
authors.forename: Brittni
authors.initials: B
authors.lastname: Morganstein
authors.forename: Alyssa
authors.initials: A
authors.lastname: Kunkel
authors.forename: Sumedh P
authors.initials: SP
authors.lastname: Surwade
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Haitao
authors.initials: H
authors.lastname: Liu