Intrinsic Wettability of Talc

Hydrophobicity of talc is traditionally considered as an intrinsic property of this mineral. Here, we show that this hydrophobicity is likely caused by airborne hydrocarbon contamination. We found that a freshly prepared talc surface is much more hydrophilic than previously reported. Upon exposure to ambient air, the water contact angle of talc increases over time. Spectroscopy analysis and control experiments indicate that this wetting transition is due to the deposition of airborne hydrocarbons, the kinetics of which are highly dependent on relative humidity.