Chemical structure and phase sequence of 8CB.
Experimental setup (a) computer controlled syringe for the manually controlled inflation of the bubbles and (b) positions of the illumination and the observation cameras.
Contrast enhanced rupture sequences of two smectic A bubbles of 8CB. (Top row) membrane thickness ; (Bottom row) membrane thickness ; scale bars 1 mm.
Distance covered by the rim from the point of puncture as a function of time t for a 27 nm thick film. The origin of the time axis was chosen with respect to the first frame after puncture. From a linear regression, one can conclude that the rupture started at t ≈ −17 μs. The rim velocity (slope of the dotted line) is approximately 29 m/s.
Comparison of the measured data with the theoretical prediction by Taylor 7 and Culick, 8 and with the previous experimental results on smectic films by Müller et al. The measured velocities are systematically smaller than predicted, in particular for thin membranes, δ < 100 nm. The dashed, dotted, and solid lines correspond to ϕ = 2, 1.5, and 1 in Eq. (1) , respectively.
Onset time for the lateral instability of the retracting film edge. There is a clear correlation with the film thickness, the onset time increases with increasing bubble thickness. The solid curve marks a linear dependence with τ = 2 μs/nm δ, the dashed curve represents a power law with τ ∝ δ3/4 as given in Eq. (2) .
The wavelength λ of the instability at onset increases with increasing film thickness. The solid curve is a linear fit, which somewhat underestimates the wavelengths observed in thin films. The dashed curve is a square root dependence, as predicted by Eq. (3) .
Flapping edge in a 140 nm thick retracting smectic film. Image (a) is a larger view of the hole, (b)–(l) is a sequence with 39.5 k fps frame rate. The white arrows point at the end of the flat film, the dark arrows at the flapping edge. The flapping frequency is approximately 7 kHz. In the last two image rows, the filamentation of the rim is visible. The size of images (a)–(l) is approximately 2.8 mm × 2.8 mm.
Comparison of the onset time τ of the lateral rim instability in a flapping film edge for smectic films and soap films. (Soap film data were kindly provided by H. Lhuissier and E. Villermaux (private communication).)
Comparison of the wavelength λ of the lateral rim instability in a flapping film edge for smectic films and soap films. (Soap film data were kindly provided by H. Lhuissier and E. Villermaux (private communication).)
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