Capillary breakup of emulsion filaments tuned by in situ gelation of dispersed droplets

We find that emulsions with a liquid internal phase exhibit viscous-dominated thinning, whereas gelation leads to elongated filaments that thin significantly more slowly. This transition appears to correlate with a shift in the ratio of viscous to elastic modulus, from greater than one to less than one, driven by gelation of the dispersed droplets and network percolation among the gel particles. These findings provide new insight into how internal-phase transitions in colloidal systems such as emulsions influence filament stability and offer design strategies for applications that require tunable breakup behavior. Moreover, the formation of colloidal gel droplets in the continuous liquid phase enables encapsulation of molecules and nanomaterials as they are deposited or printed.