Enhanced instability in thin liquid films by improved compatibility

We investigated experimentally the morphological evolution of thin polydime thylsiloxane films sandwiched between a silicon wafer and different boundin g liquids with interfacial tensions varying by 2 orders of magnitude. It is shown that increasing the compatibility between film and bounding liquid b y adding a few surfactant molecules results in a faster instability of shor ter characteristic wavelength. Inversely, based on the characteristic param eters describing the instability we determined extremely small interfacial tensions with a remarkable accuracy.