The inner-structure of polypyrrole (PPy) nanoparticles can be straightly adjusted by a simple alcohol-assisted microemulsion polymerization. The characteristic peaks of PPy in infrared spectroscopy (IR) confirm the formation of PPy. The morphology of PPy nanoparticles was characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). UV-vis and Raman spectra exhibit that the conjugation and order of PPy chains were improved directly in the presence of alcohols and adjusted by the alkyl unit of alcohols. These changes in the molecular structure lead to the improvement in the electrical conductivity of as-prepared PPy nanoparticles obviously. (c) 2005 Elsevier B.V. All rights reserved.