Search results for: Jee-Hyun Ryu

Items from 1 to 16 out of 16 results

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Non‐invasive Transdermal Delivery Route Using Electrostatically Interactive Biocompatible Nanocapsules

Jinseob Shin, Kyomin Shin, Hanna Lee, Jeong‐Beom Nam, more

A robust means of fabricating skin‐penetrating and compatible nanocarriers comprising poly(D, L‐lactide‐co‐glycolide) is reported. The resultant nanocapsules have the ability to load biologically active ingredients and selectively release them through the epidermis lipid layer. Their release of genistein (left figure) is determined to be diffusion‐controlled, and they are shown to successfully deliver...

article

Influence of viologen lengths on the response time of the reflective electrochromic display prepared by monodisperse viologen-modified polymeric microspheres

Jee-Hyun Ryu, Jung-Hun Lee, Seung-Jin Han, Kyung-Do Suh

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2008 > 315 > 1-3 > 31-37

To improve the response time of reflective electrochromic display (R-ECD), the distance between particle surface and viologen moiety was controlled. Firstly, cyano-functionalized polymeric microspheres were prepared by seeded polymerization and then the synthesized viologen compounds, containing alkyl chains of varying lengths, were reacted on the surface of the microspheres. Faster response time...

article

Monodisperse micrometer-ranged poly(methyl methacrylate) hybrid particles coated with a uniform silica layer

Seung-Jin Han, Kyomin Shin, Kyung-Do Suh, Jee-Hyun Ryu

Macromolecular Research > 2008 > 16 > 5 > 399-403

Monodisperse, micron-sized, hybrid particles having a core-shell structure were prepared by coating the surface of poly(methyl methacrylate)(PMMA) microspheres with silica and by copolymerizing acrylamide (AAm) to supply the hydrogen bonding effect by means of the amide groups. Tetraethoxysilane (TEOS) was then slowly dropped onto the medium under certain conditions. Because of the hydrogen bonding...

article

Electrorheological properties of carbon nanotubes-coated monodisperse polymeric microspheres

Bumsu Kim, Yun-Ho Lee, Seung-Jin Han, Jee-Hyun Ryu, more

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2007 > 298 > 3 > 245-251

Monodisperse polymeric microspheres coated by single- and multi-wall carbon nanotubes were prepared and applied to electrorheological (ER) fluids. First, functionalized carbon nanotubes (fCNTs) were prepared by the chemical oxidation method. Then, the polymeric particles were functionalized by incorporating glycidyl methacrylate. Epoxy rings on the particles surface were modified to amine groups by...

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Influence of SMA content on the electro-optical properties of polymer-dispersed liquid crystal prepared by monodisperse poly(MMA-co-SMA)/LC microcapsules

Jee-Hyun Ryu, Sung-Guk Lee, Jeong-Beom Nam, Kyung-Do Suh

European Polymer Journal > 2007 > 43 > 5 > 2127-2134

Monodisperse poly(methyl methacrylate) (PMMA) particles containing various concentrations of stearyl methacrylate (SMA) were prepared, and a liquid crystal (LC) was swollen into the particles using a solute co-diffusion method (SCM). Phase separation behaviors between the polymer and LC were monitored by utilizing an optical and a polarized microscope (OM/POM). The monodisperse LC microcapsules were...

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Effect of particle diameter on the electro-optical property of reflective electrochromic display based on monodisperse viologen-modified polymeric microspheres

Jee-Hyun Ryu, Min-Su Park, Kyung-Do Suh

Colloid and Polymer Science > 2007 > 285 > 15 > 1675-1681

A reflective electrochromic display (R-ECD) based on viologen-modified polymeric microspheres was prepared and the influence of particle size on the electro-optical characteristics was investigated. The diameters of the viologen-modified polymeric microspheres were altered changing the solvency of the medium during the dispersion polymerization. The chloro-functionalized polymeric microspheres were...

article

Electro-optical properties of polymer-dispersed liquid crystal prepared by monodisperse poly(methyl methacrylate)/fluorinated liquid crystal microcapsules

Jee-Hyun Ryu, Young-Hun Choi, Kyung-Do Suh

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2006 > 275 > 1-3 > 126-132

A liquid crystal (LC) containing the fluorine group was encapsulated into poly(methyl methacrylate) (PMMA) particles by using the solute co-diffusion method (SCM). The PMMA/LC composites were applied to a polymer-dispersed liquid crystal (PDLC) and their electro-optical properties were investigated. The medium solvency, methylene chloride (MC) content, and the crosslinking density of substrate particles...

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Enhanced colloidal properties of single-wall carbon nanotubes in α-terpineol and Texanol

Bumsu Kim, Yun-Ho Lee, Jee-Hyun Ryu, Kyung-Do Suh

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2006 > 273 > 1-3 > 161-164

The solubility of single-wall carbon nanotubes (SWCNTs) in solvents is a critical factor for the potential applications of SWCNTs. Recently, it has been reported that SWCNTs are relatively well-dispersed in organic amide solvents, such as, dimethylformamide (DMF). However, it is still a challenge to disperse and to stabilize SWCNTs in solvents for further chemical reactions. In this research, α-terpineol...

article

Stabilization of resveratrol immobilized in monodisperse cyano-functionalized porous polymeric microspheres

Jeong-Beom Nam, Jee-Hyun Ryu, Jin-Woong Kim, Ih-Scop Chang, more

Polymer > 2005 > 46 > 21 > 8956-8963

To preserve the high anti-oxidant activity of resveratrol for a long period of time, porous particles were utilized. The porosity of these substrate particles was controlled by DVB content and toluene/heptane ratios in the seeded polymerization. The influence of porosity on the anti-oxidant activity of the immobilized resveratrol was investigated. From SEM and CLSM analysis, it was confirmed that...

article

Surface modification of monodisperse hydroxyl functionalized polymeric microspheres using ceric ammonium nitrate

Seong-Heun Cho, Jee-Hyun Ryu, Jin-Gyu Park, Kyung-Do Suh

European Polymer Journal > 2005 > 41 > 10 > 2209-2215

The surface modification of monodisperse hydroxyl functionalized polymeric microspheres was carried out by utilizing a redox initiation system. Styrene, divinylbenzene and hydroxyethyl methacrylate were used as the second monomer in the seeded polymerization. An excessive amount of the second monomer emulsion was swollen into the polystyrene (PS) seed particles completely by controlling the medium...

article

Synthesis and characterization of monodisperse magnetic composite particles for magnetorheological fluid materials

Jung-Bae Jun, Seong-Yong Uhm, Jee-Hyun Ryu, Kyung-Do Suh

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2005 > 260 > 1-3 > 157-164

Monodisperse magnetic composite particles (MCP) were prepared and characterized for a study of magnetic field-responsive fluids. Magnetic composite particles used are iron oxide-coated polymer composite particles, which were synthesized through in situ coating of iron oxide onto pre-existing polymer particles by the reduction of ferrous fluids. For a uniform and bulk coating of iron oxide, the porous...

article

Preparation of monodisperse poly(divinylbenzene) macrobeads via a drop breaking and polymerization method

Seong-Heun Cho, Jung-Bae Jun, Jee-Hyun Ryu, Kyung-Do Suh

Colloids and Surfaces A: Physicochemical and Engineering Aspects > 2005 > 254 > 1-3 > 1-7

Monodisperse polydivinylbenzene macrobeads over 100μm in diameter were prepared by using a drop breaking and polymerization technique. The monomer droplets formed by the nozzle were stabilized by polyvinyl alcohol solution, which is used as a carrier fluid, and moved to a reactor along the polytetraflouroethylene tube, then polymerized. The monomer viscosity, piston pump velocity, and syringe pump...

article

Monodisperse chloromethyl-functionalized macroporous polymer particles by seeded polymerization in aqueous media

Jin-Woong Kim, Jin-Gyu Park, Jee-Hyun Ryu, Ih-Seop Chang, more

Colloid and Polymer Science > 2005 > 283 > 11 > 1233-1240

This study presents a method to produce monodisperse chloromethyl-functionalized macroporous poly(styrene-co-divinylbenzene) polymer particles by seeded polymerization in aqueous media. We observed that the molecular structure of polystyrene seed particles, the composition of the secondary monomer mixtures, and the type of solvents were very important factors that determine the morphology and porosity...

article

Monodisperse polystyrene particles crosslinked with poly(dimethyl siloxane) diacrylate using dispersion polymerization and their monomer swelling capability

Seong-Heun Cho, Jee-Hyun Ryu, Jung-Bae Jun, Kyung-Do Suh

Colloid and Polymer Science > 2005 > 284 > 3 > 266-275

A flexible poly(dimethyl siloxane) diacrylate (PDMSDA) crosslinker was synthesized using different molecular weights of poly(dimethyl siloxane) (PDMS, M _n=550, 1,700, 4,000 g/mol). The monodisperse polystyrene (PS) particles crosslinked with various contents of PDMSDA were prepared by dispersion polymerization, and applied as seed particles in the seeded polymerization. The crosslinking density...

article

Synthesis of silver/polymer colloidal composites from surface-functional porous polymer microspheres

Jin-Woong Kim, Jung-Eun Lee, Su-Jin Kim, Jong-Suk Lee, more

Polymer > 2004 > 45 > 14 > 4741-4747

This study presents a different colloidal silver (Ag)/polymer system where Ag nanoparticles are deposited uniformly onto surface-functional porous poly(ethylene glycol dimethacrylate-co-acrylonitrile) (poly(EGDMA-co-AN)) microspheres. The formation and morphology of the composite microspheres were characterized from electron microscopy and X-ray diffraction analyses. The significance of the present...

article

Polymer/Ag composite microspheres produced by water-in-oil-in-water emulsion polymerization and their application for a preservative

Jung-Eun Lee, Jin-Woong Kim, Jung-Bae Jun, Jee-Hyun Ryu, more

Colloid and Polymer Science > 2004 > 282 > 3 > 295-299

Nanosized Ag particles were entrapped successfully in multihollow porous poly(methyl methacrylate) (PMMA) microspheres by water-in-oil-in-water emulsion polymerization. The structure of the PMMA/Ag microspheres prepared was characterized by scanning electron microscopy and X-ray powder diffraction analysis. It was found that the Ag nanoparticles were impregnated in the inner voids of the microspheres...

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