How long is the long-range hydrophobic attraction?

We present direct surface force measurements performed using smooth and robust hydrophobic monolayers deposited on mica. From atomic force microscopy measurements we show that these surfaces are composed of large polymerized domains surrounded by a less densely packed, probably gaseous, phase. They exhibit electrical neutrality and stability on exposure to water and aqueous electrolyte solution and are, we suggest, relatively defect free. Despite these characteristics, these novel surfaces do not show the typical long-range hydrophobic interaction that is often associated with good quality hydrophobic films. However, we believe that the quality of these surfaces provides the dearest characterization of the interaction between macroscopic hydrophobic surfaces to date and that the novel observation of spontaneous cavitation occurring between these hydrocarbon films is further proof of the suitability of these surfaces in such an investigation.