An interpenetrating polymer network (IPN) combining a hydrophobic polymer (polydimethylsiloxane, PDMS) and a hydrophilic polymer (polyvinylpyrrolidone, PVP) was synthesized in different solvents via a two-step preparation method. The solvent used during polymerization of the IPN showed a significant impact on the properties of the PVP/PDMS-IPN. The choice of solvent was affecting both the wettability and transparency of the PVP/PDMS-IPN. The PVP/PDMS-IPNs turned hydrophilic in all the solvents used in this study, but the transition from a hydrophobic to a hydrophilic PVP/PDMS-IPN occurred at lower PVP concentration if a solvent with similar solubility parameter as PVP was chosen. Also, the PVP/PDMS-IPNs were transparent when the samples were polymerized in a good solvent for PVP. It was concluded that the properties of the PVP/PDMS-IPN can be tuned by the selection of the solvent used during polymerization. The size of the PVP phase domains in the PVP/PDMS-IPNs were analyzed with X-ray scattering techniques (SAXS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC), and the sizes of the domains were found to be smaller than 350 nm. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1828-1839, 2009