Figure 4
DoS images and schematic of proposed film formation for 3 mg/mL PEO/chloroform (no chamber). (a) Trial 1 exhibits subcritical film formation, where a connected film fails to span the entire bridge surface. (b) In trial 2, a critical film spans the entire surface, lengthening \(t_{b}\) and \(\lambda _{E}\) substantially. In both trials, the film has already formed by the time the drop contacts the substrate and begins to thin (frame 1). However, while trial 1 maintains axial symmetry, symmetry is broken in trial 2 and the surface film dominates thinning, explaining the large deviations in \(\lambda _{E}\) and breakup time for PEO/chloroform trials performed outside of the chamber.
