Mu Sang Lee

Bio: Mu Sang Lee is an academic researcher from Kyungpook National University. The author has contributed to research in topics: Nanocomposite & Thermogravimetric analysis. The author has an hindex of 20, co-authored 34 publications receiving 1132 citations.

Synthesis and characterization of conducting polythiophene/carbon nanotubes composites

Abstract: Conducting polythiophene (PTh)/single-wall carbon nanotubes (SWNTs) composites were synthesized by the in situ chemical oxidative polymerization method. The resulting cablelike morphology of the composite (SWNT–PTh) structures was characterized with elemental analysis, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared, ultraviolet–visible spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, X-ray diffraction, and transmission electron microscopy. The standard four-point-probe method was used to measure the conductivity of the samples. Field emission scanning electron microscopy and transmission electron microscopy analysis revealed that the SWNT–PTh composites were core (SWNTs) and shell (PTh) hybrid structures. Spectroscopic analysis data for the composites were almost identical to those for PTh, supporting the idea that SWNTs served as templates in the formation of a coaxial nanostructure for the composites. The physical properties of the composites were measured and also showed that the SWNTs were modified by conducting PTh with an enhancement of various properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5283–5290, 2006

Synthesis of core-shell silver–polyaniline nanocomposites by gamma radiolysis method

Abstract: Core-shell silver (Ag)–polyaniline (PAni) nanocomposites have been synthesized by the in-situ gamma radiation-induced chemical polymerization method. Aqueous solution of aniline, a free-radical oxidant, and/or silver metal salt were irradiated by γ-rays. Reduction of the silver salt in aqueous aniline leads to the formation of silver nanoparticles which in turn catalyze oxidation of aniline to polyaniline. The resultant Ag-PAni nanocomposites were characterized by using different spectroscopy analyses like X-ray photoelectron, UV–visible, and infrared spectroscopy. The optical absorption bands revealed that the bands at about 400 nm are due to the presence of nanosilver and the blue-shifted peak at ∼ 555 nm is due to the presence of metallic silver within the PAni matrix. X-ray diffraction pattern clearly indicates the broad amorphous polymer and the sharp metal peaks. Scanning electron microscopy and transmission electron microscopy of the nanocomposite showed a uniform size distribution with spherical and granular morphology. Thermogravimetric analysis revealed that the composites have a higher degradation temperature than polyaniline alone. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5741–5747, 2007

SERS of dithiocarbamate pesticides adsorbed on silver surface; Thiram

Abstract: In the present work, we studied thiram on silver surface by SERS. Investigations of disulfides with SERS revealed that the molecules undergo a surface reaction on silver, namely easy cleavage of the S-S bond. We believe that the two S atoms of resonance formed from the thiram may be chemisorbed strongly on Ag sol. This resonance form adheres perpendicularly to the Ag surface via the two S atoms, since the δ (CH3) and ν (CN) mode perpendicular to the surface showed strong enhancement. The important roles of halide anion adsorption have been discussed and the pH effects of thiram on Ag sol in acidic, neutral, and alkaline conditions were examined.