In this work, we performed impedance spectroscopy measurements of organically modified silicate membranes based on polydimethylsiloxane (PDMS) and tetraethoxysilane (TEOS) with the inclusion of sodium dodecyl sulfate (SDS) at five different concentrations. The results indicated that the conduction in a pure PDMS/TEOS hybrid membrane mainly resulted from a hopping mechanism. The conduction of membranes modified with the addition of SDS increased for SDS concentrations up to 20% and decreased for higher concentrations. This effect was explained on the basis of the porosity of the membranes due to SDS. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 851-854, 2010