Poly(dimethylsiloxane) (PDMS) and a poly(DMS-styrene) block copolymer were compared as extraction and optical detection media for hydrophobic compounds in water and water/ethanol solutions. Partitioning to both polymers increased exponentially with increased percent water in ethanol. Partition coefficients to the copolymer were 1030-fold higher than to PDMS. Ultraviolet absorbance spectra of pyrene showed a 4-nm red-shift in copolymer versus PDMS, providing evidence of pp interactions, accounting for greater partitioning. The extinction coefficient coefficient of pyrene at 334 nm was twice as high in the copolymer as in PDMS. The combination of higher affinity for polycyclic aromatic hydrocarbons with higher absorbance make poly(DMS-styrene) copolymers promising material for extraction and in situ detection of hydrophobic aromatic compounds in water. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012