The behavior of methanol adsorption on platinum/poly(2,5-dimethoxyaniline) (Pt/PDMA) composite is investigated using UV-vis spectroscopy (UV-vis) and open circuit potential (OCP). The results of scanning electron microscopy and energy dispersive spectroscopy are used to verify the uniform dispersion of Pt in PDMA. The Fourier transform infrared spectra and OCP results revealed that Pt particles interact with PDMA through the electron-rich nitrogen sites, influencing the oxidation state of PDMA. A model is proposed for the methanol adsorption on Pt particles which changes the interaction between Pt and PDMA. With the proposed model, methanol concentration can be discerned using potentiometric measurements. The results of this Study can be applied to methanol sensors for direct methanol fuel cells. (C) 2008 Elsevier B.V. All rights reserved.