Fig. S7.

An enlarged view of the tensiometric force curve for the first receding measurement shows sawtooth waves corresponding to the stick-slip of capillary fingers at the receding contact line. The Upper Inset figure shows the power spectrum of a 1D Fourier transform of the sawtooth waves, with a primary peak at 800 μm, in good agreement with the spacing between creases shown in the Lower Left Inset optical micrograph. The large spectral noise observed in the power spectrum is due to the limited number of creases that can be probed in the tensiometry measurement. Nevertheless, this data in conjunction with Fig. 4B together confirm that stick-slip periodicity in tensiometry measurement matches the average spacing of creases.