Condensing droplets on the soft surfaces with varying shear modulus

The behavior of the liquid drops on the soft surfaces during condensation has been intriguing due to the viscoelastic nature of the substrates. The effects of viscoelastic characteristics during condensation are poorly understood due to the substrate's deformability, which is influenced by elastic and interfacial tension forces acting at the solid–liquid interface. The rheology of soft substrates plays a significant role during condensation, influencing several processes such as droplet growth, drop coalescence, contact line motion, and wetting ridge dynamics. This study investigated these condensation processes on soft polydimethylsiloxane (PDMS) substrates with varying shear moduli. We observed a higher drop coverage fraction and an average condensate drop size on the soft surface with a low shear modulus magnitude. Regardless of the shear moduli of the PDMS substrates, the relaxation time of coalescing drops follows a linear trend with the drop equilibrium size, with the magnitude being higher for softer substrates.