Evaporation of sessile water droplet on polydimethylsiloxane (PDMS) surfaces with three different curing ratios (5 : 1, 10 : 1, and 20 : 1) was experimentally investigated in this paper. We show that the constant contact radius (CCR) evaporation on surface with high curing ratio lasts longer than that with low curing ratio. We also measured Young's moduli of PDMS films by using atomic force microscopy (AFM) and simulated surface deformation of PDMS films induced by sessile water droplet. With increasing curing ratio of PDMS film, Young's modulus of PDMS film is getting lower, and then there will be larger surface deformation and more elastic stored energy. Since such energy acts as a barrier to keep the three-phase contact line pinned, thus it will result in longer CCR evaporation on PDMS surface with higher curing ratio.

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