Yong Joo Kim

A STUDY ON A NEW SYNTHETIC METHOD OF CdS AND CdSe NANOPARTICLES AND THEIR ORGANIC/INORGANIC NANOCOMPOSITE

Materials such as CdS and CdSe inorganic nanoparticles have photoluminescence. Sodium oleate has been used as effective stabilizers for the synthesis of CdS and CdSe nanoparticles in water by autoclave method. Photoluminescence of CdS and CdSe with particle size of 5–14 nm showed λmax at 520 nm and 600 nm, respectively, when were excited at 365 nm. These nanoparticles doped into the PVA resulted in the organic/inorganic films (PVA/CdS, CdSe). Photoluminescence, X-ray diffraction and transmission electron microscopy were employed for their characterization.

The Synthesis and Characterization of SmCo Magnetic Nanoparticle by Thermal Decomposition

The magnetic nanoparticle of SmCo was synthesized as thermal decomposition of metal salt by using pyrex bottle in the furnace. The magnetic properties of SmConanoparticle were compared according to the ratio of Sm and Co component. The size of nanoparticle was confirmed by transmission electron microscopy (TEM) and scanning electron microscopy images (SEM). The crystal structure of nanoparticle was characterized by X-ray diffraction pattern (XRD). The magnetic properties were characterized with saturation magnetization from hysteresis loop by vibrating sample magnetometer (VSM).

Preparation of Heat Insulating Nanocomposite Film with MPS (Mercaptopropyl Trimethoxysilane) Coated-Nanoparticles

ABSTRACT To improve the heat insulating property of plastic films, SiO2 nanoparticles as inorganic insulating filler were prepared from sodium metasilicate by emulsion method in reverse micelle. MgO, Al2O3 and CaO nanoparticles were also prepared. Surface modifications of synthesized heat insulating nanoparticles were accomplished with MPS (mercaptopropyl trimethoxysilane) coating to maximize homogeneous distribution and compatibility between obtained heat insulating nanoparticles and EVA (ethylene vinylacetate). Finally heat insulating films were prepared with MPS coated-heat insulating nanoparticles at the ratio of 2 wt% and EVA. The insulating capacity was tested by IR spectroscopy and light transmission was observed by UV-vis spectroscopy. The mechanical properties such as tensile strength, elongation, impact strength, tear strength, clarity and haze were also studied.

Characterization of Photochromic Azobenzene Derivatives in the Liquid Crystalline Matrix

We investigated on the photoisomerization of azobenzene derivatives in liquid crystalline matrix that is 4-pentyl-4-bisphenyl carbonitrile (5CB) for holographic memory. In order to investigate of photoisomerization of azobenzene derivatives at the air/water interface, the azobenzene derivative having side chain monomer with alkyl chain was synthesized. The azobenzene derivatives in liquid crystalline matrix were characterized by the measurements of UV-vis spectroscopy, photorefractive index by two-beam coupling (2CB).