10.1021/acs.langmuir.6b00779.s001 Victoria C. Harrold Victoria C. Harrold Maxime Paven Maxime Paven Doris Vollmer Doris Vollmer James S. Sharp James S. Sharp Rheological Properties of Viscoelastic Drops on Superamphiphobic Substrates American Chemical Society 2016 measurement refracting laser light rheological properties photodiode vibration solution frequency 2016-04-01 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Rheological_Properties_of_Viscoelastic_Drops_on_Superamphiphobic_Substrates/3171913 The rheological properties of microliter sized drops of polymer solutions were investigated using measurements of their mechanical vibrational response. Drops were suspended on superamphiphobic substrates and vibrated by the application of a short mechanical impulse. Surface vibrations were monitored by refracting laser light through the drops and focusing the refracted light onto the surface of a photodiode. Time dependent variations in the photodiode output were Fourier transformed to obtain the frequency and spectral width of the mechanical resonances of the drops. These quantities were related to the frequency dependent shear storage and loss moduli (<i>G</i>′ and <i>G</i>″, respectively) using a simple theoretical model. The resulting rheological properties were found to be in agreement with microrheology measurements of the same solutions. Drop vibration therefore provides a fast and accurate method of quantifying the rheological properties of single drops.