• Macromolecular Research
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• v.16 no.7
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• pp.604-608
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• 2008

Color dye-doped silk fibroin nanoparticles were successfully fabricated using a microemulsion method. An aqueous silk fibroin solution was prepared by dissolving cocoons (Bombyx mori) in a concentrated lithium bromide solution followed by dialysis. A color dye solution was also mixed with the aqueous silk fibroin solution. The surfactants used for the microemulsion were then removed by methanol and ethanol, yielding color dye-doped silk fibroin nanoparticles, approximately 167 nm in diameter. The secondary structure of the nanoparticles showed a $\beta$-sheet conformation, as characterized by Fourier transform infrared spectroscopy. The morphology of the nanoparticles was determined by field emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy, and their size and size distribution were measured by dynamic light scattering. The color dye-doped silk fibroin nanoparticles were examined by confocal laser scanning microscopy.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.26-34
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• 2016

In this study, core-crosslinked amphiphilic polymer (CCAP) nanoparticles prepared using a reactive amphiphilic polymer precursor (RARP) were used for preparing some valuable compounds encapsulated polymer nanoparticles with high payload through nanoprecipitation process. Various solvents (acetone, ethanol, and THF) having different polarity and CCAP nanoparticles prepared using different amphiphilicity were used for the preparation of ${\alpha}$-tocopherol encapsulated polymer nanoparticles to investigate their effects on the encapsulation efficiency, payload, nanoparticle size, and stability. CCAP dissolved in hydrophobic solvent, THF, could form ${\alpha}$-tocopherol encapsulated polymer nanoparticles dispersed in water with the high payload of ${\alpha}$-tocopherol and encapsulation efficiency. Because of their physically and chemically robust nano-structure originated from crosslinking of the hydrophobic core, CCAP nanoparticles could encapsulate ${\alpha}$-tocopherol with the high payload (33 wt%) and encapsulation efficiency (97%), and form 70 nm-sized stable nanoparticles in water.

• Macromolecular Research
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• v.16 no.2
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• pp.85-102
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• 2008

The development of reliable synthetic routes to polymer nanomaterials with well-defined size and morphology is a critical research topic in contemporary materials science. The ability to generate nanometer-sized polymer materials can offer unprecedented, interesting insights into the physical and chemical properties of the corresponding materials. In addition, control over shape and geometry of polymer nanoparticles affords versatile polymer nanostructures, encompassing nanospheres, core-shell nanoparticles, hollow nanoparticles, nanorods/fibers, nanotubes, and nanoporous materials. This review summarizes a diverse range of synthetic methods (broadly, hard template synthesis, soft template synthesis, and template-free synthesis) for fabricating polymer nanomaterials. The basic concepts and significant issues with respect to the synthetic strategies and tools are briefly introduced, and the examples of some of the outstanding research are highlighted. Our aim is to present a comprehensive review of research activities that concentrate on fabrication of various kinds of polymer nanoparticles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.119-122
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• 2003

We report a dramatic increase in the photo-stability of a blue-emitting polymer, poly(9,9-dioctylfluorene), achieved by the addition of gold nanoparticles to the polymer. The optical absorption band of gold nanoparticles is tuned to resonate the triplet exciton-ground state band gap energy of the polymer. The photo-oxidation rate of poly(9,9-dioctylfluorene) was drastically reduced by doping the polymer with a very small amount ($10^{-6}-10^{-5}$ volume fraction) of gold nanoparticles. The gold nanoparticles used herein act as the quenching agent of the triplet states and can be directly applied to various blue light emitting polymer thin film ( < 100 nm ) devices.

• Macromolecular Research
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• v.17 no.3
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• pp.187-191
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• 2009

Platinum (Pt) nanoparticles were prepared by the liquid-phase reduction of tetraammineplatinum (II) chloride $([Pt(NH_3)_4]Cl_2)$ using Nafion as a stabilizer under various conditions of the Nation phase. This method is novel in its use of electrostatic interactions between the Pt complex ions and sulfonic groups in the hydrated Nation molecules. The synthesized Pt nanoparticles of the recast film system had a cubic shape. In the case of the Nation solution system, the Pt nanoparticles mainly had a spherical shape. The shapes and sizes of the Pt nanoparticles were strongly influenced by the Nation phase.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.283-283
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• 2006

Multigram-scale product exclusively containing magnetic carbon nanoparticles (MNCPs) with uniform size was successfully fabricated without a specific separation process. The iron-doped PPy nanoparticles were synthesized by micelle templating and used as the carbon precursor in order to generate MCNPs. The magnetic carbon nanoparticles possessed a microporous structure and exhibited ferromagnetic properties at room temperature. This approach may be an effective alternative to generate magnetic carbon nanoparticles against the conventional arc-discharge technique.

• Macromolecular Research
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• v.14 no.1
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• pp.66-72
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• 2006

The purpose of this study is to develop novel nanoparticles based on polyion complex formation between low molecular weight water-soluble chitosan (LMWSC) and all-trans retinoic acid (atRA). LMWSC nanoparticles encapsulating atRA based on polyion complex were prepared by mixing of atRA into LMWSC aqueous solution using ultrasonication. In FTIR spectra, the carbonyl group of atRA at 1690 $cm^{-1}$ disappeared or decreased when ion complexes were formed between LMWSC and atRA. In ${1}^H$ NMR spectra, specific peaks of atRA disappeared when atRA-encapsulated LMWSC (RAC) nanoparticles were reconstituted into $D_{2}O$ while specific peaks both of atRA and LMWSC appeared in $D_{2}O$/DMSO (1/3, v/v) mixture. XRD patterns also showed that the crystal peaks of atRA were disappeared by encapsulation into LMWSC nanoparticles. LMWSC nanoparticles encapsulating atRA have spherical shapes with particle size below 200 nm. The mechanism of encapsulation of atRA into LMWSC nanoparticles was thought to be an ion complex formation between LMWSC and atRA. LMWSC nanoparticles showed high atRA loading efficiency over 90$\%$ (w/w). AtRA was continuously released from nanoparticles over 10 days. In in vitro cell cytotoxicity test, free atRA showed higher cytotoxic effect against CT 26 colon carcinoma cell line on 1 day. However, RAC nanoparticles showed similar cytotoxicity against CT 26 cells on 2 day. These results suggest the potential for the introduction of LMWSC nanoparticles into various biomedical fields such as drug delivery.

• Macromolecular Research
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• v.14 no.2
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• pp.146-154
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• 2006

Organic and inorganic hybrid nanocomposites based on poly(ethylene 2,6-naphthalate) (PEN) and silica nanoparticles were prepared by a melt blending process. In particular, polymer nanocomposites consisting mostly of cheap conventional polyesters with very small quantities of inorganic nanoparticles are of great interest from an industrial perspective. The crystallization behavior of PEN/silica hybrid nanocomposites depended significantly on silica content and crystallization temperature. The activation energy of crystallization for PEN/silica hybrid nanocomposites was decreased by incorporating a small quantity of silica nanoparticles. Double melting behavior was observed in PEN/silica hybrid nanocomposites, and the equilibrium melting temperature decreased with increasing silica content. The fold surface free energy of PEN/silica hybrid nanocomposites decreased with increasing silica content. The work of chain folding (q) for PEN was estimated as $7.28{\times}10^{-20}J$ per molecular chain fold, while the q values for the PEN/silica 0.9 hybrid nanocomposite was $3.71{\times}10^{-20}J$, implying that the incorporation of silica nanoparticles lowers the work required to fold the polymer chains.

• Polymer(Korea)
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• v.34 no.6
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• pp.491-494
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• 2010

Colored, electrophoretic polymer nanoparticles of poly (styrene-co-divinylbenzene-co-vinyl acetate)[poly(St-co-DVB-co-VAc)] were prepared by emulsifier-free emulsion co-polymerization and reactive dyeing. The emulsifier-free emulsion polymerization of styrene, divinyl benzene and vinyl acetate was carried out at $70^{\circ}C$ for 20 hrs to obtain monodisperse polymer nanoparticles of poly(St-co-DVB-co-VAc) with an average diameter of 180~200 nm. These nanoparticles were transformed into poly(styrene-co-divinylbenzene-co-vinyl alcohol) [poly(St-co-DVB-co-VA)] nanoparticles through the saponification reaction. The poly(St-co-DVB-co-VA) nanoparticles were treated with reactive dyes to obtain the colored, monodisperse electrophoretic nanoparticles, and their morphology and surface charge were characterized by scanning electron microscopy, differential scanning calorimetry, UV/Vis absorbance and zeta-potentiometry.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1683-1688
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• 2007

This paper presents a novel simple method for introducing gold nanoparticles in a poly(4-vinylpyridine) (PVP) polymer layer over a glassy carbon (GC) electrode with the aim of forming a tunable electrochemical interface against a cationic ruthenium complex. Initially, AuCl4 ? ions were spontaneously incorporated into a polymer layer containing positively charged pyridine rings in an acidic media by ion exchange. A negative potential was then applied to electrochemically reduce the incorporated AuCl4 ? ions to gold nanoparticles, which was confirmed by the FE-SEM images. The PVP layer with an appropriate thickness over the electrode blocked electron transfer between the electrode and the solution phase for the redox reactions of the cationic Ru(NH3)6 2+ ions. However, the introduction of gold nanoparticles into the polymer layer recovered the electron transfer. In addition, the electron transfer rate between the two phases could be tuned by controlling the number density of gold nanoparticles.