Fig. 2.

Representative force curves measured between surfaces hydrophobized by three different techniques. (a) Short-range attraction typical between stable surfaces. [Reproduced with permission from ref. 54 (Copyright 1995, American Chemical Society).] (b) Long-range, biexponential attraction between physisorbed or self-assembled surfactant surfaces. (c) Step-like force curves indicative of bridging nanobubbles. [Reproduced with permission from ref. 73 (Copyright 1994, American Chemical Society).]