Wetting of Substrates with Phase-Separated Binary Polymer Mixtures

We investigate a wetting reversal transition in thin films of two-phase mixtures of poly(ethylene-propylene) (PEP) and its deuterated analog (dPEP) on substrates covered by self-assembled monolayers (SAM) whose surface energy, ${\ensuremath{\gamma}}_{\mathrm{SAM}}$, is tuned by varying the SAM composition. As ${\ensuremath{\gamma}}_{\mathrm{SAM}}$ increases from 21 to $24\mathrm{mJ}/{\mathrm{m}}^{2}$, a transition from a dPEP/PEP/dPEP/SAM to a dPEP/PEP/SAM structure occurs at increasing ${T}_{C}\ensuremath{-}T$, where ${T}_{C}$ and $T$ are the critical and transition temperatures, respectively. The dependence of $T$ on ${\ensuremath{\gamma}}_{\mathrm{SAM}}$ is predicted by a simple model from surface and interfacial energies of PEP/dPEP.