Water-Dispersible Magnetic Polyaniline Nanocomposites

Brian Berry1 and Tito Viswanathan2

1 Polymer Division, National Institute of Standards and Technology

2Department of Chemistry, University of Arkansas at Little Rock

 

Polyanilines as well as polyaniline nanocomposites have been touted as excellent materials for radar evasion and electromagnetic interference shielding.  However, the use of these materials for such applications has been limited by their poor dispersibility. In this study, water-dispersible magnetic polyaniline nanocomposites were synthesized using lignosulfonic acid, a renewable resource, as an acid/template.  Magnetic nanocrystals were synthesized via hydrothermal and coprecipitation techniques in the presence of the lignosulfonic acid followed by the in-situ polymerization of aniline.  Conductivities of all the samples were found to remain relatively constant in the 100 S/cm range for samples containing 0-45% by weight magnetic nanocrystals.  The crystal sizes of the nanocomposites synthesized using the hydrothermal method were determined to be between 10 and 66 nm using XRD.  This size was influenced greatly by the initial amount of ferrous salts in the reaction mixture.  Mössbauer spectroscopy indicated that the magnetic nanocrystals formed was nonstoichiometric magnetite.  The crystal size for samples synthesized via the coprecipitation method was calculated to be approximately 6 nm and was found to be independent of the initial amount of ferrous salts in the reaction mixture.  Variable temperature Mössbauer spectroscopy confirmed that the crystals formed using this method exhibited superparamagnetic behavior.  All of the nanocomposite samples exhibited appreciable dispersibility in aqueous systems. 

 

 

Author Information:

Brian Berry

Mentor: Ronald Jones

Polymer Division

Building 224, B230, MS 8541

Phone: x5696

Fax: 301-975-3928

brian.berry@nist.gov

Not a Sigma Xi member

Poster Category: Materials