Conducting polyaniline-polymannuronate (PANI-PM) composites were synthesized via in situ deposition techniques. By dissolving different weight percentages of polymannuronate (PM) (5, 10, 15, and 25%), the oxidative polymerization of aniline was achieved through the use of ammonium persulfate as oxidant. Structural morphology, FT-IR, and X-ray diffraction (XRD) studies support a strong interaction between PANI and PM. The temperature-dependent DC conductivity of PANI-PM composites was studied within the range of 300 <= T <= 500 degrees K, presenting evidence for the transport properties of PANI-PM composites. Conductivity was analyzed through Mott's equation, which leveraged the variable range hopping model in three dimensions. Parameters such as density of states at the Fermi energy, hopping energy, and hopping distance were calculated. Based on the above factors, the synthesis of PANI-PM composites envisages the future development of biomimetic materials for the creation of a new bionanocomposite as a multicomponent and multifunctional material. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 36-45, 2009