• Macromolecular Research
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• 제15권4호
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• pp.330-336
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• 2007

Luminescent CdSe/ZnS QDs, with emission in the red region of the spectrum, were synthesized and encapsulated in poly(ethylene glycol)-poly(D,L-lactide) diblock copolymer micelles, to prepare water-soluble, bio-compatible QD micelles. PEG-PLA diblock copolymers were synthesized by ring opening polymerization of D,L-lactide, in the presence of methoxy PEG as a macro initiator. QDs were encapsulated with PEG-PLA polymers using a solid dispersion method in chloroform. The resultant polymer micelles, with encapsulated QDs, were characterized using various analytical techniques, such as UV- Vis measurement, light scattering, fluorescence spectroscopy, transmission electron microscopy (TEM) and atomic forced microscopy (AFM). The polymer micelles, with encapsulated QDs, were spherical and showed diameters in the range of 20-150 nm. The encapsulated QDs were highly luminescent, and have high potential for applications in biomedical imaging and detection.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.211-217
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• 2014

A new needle-based device for headspace wire coated in-needle microextraction (HS-WC-INME) was fabricated using a nichrome wire coated with poly(ethylene glycol) (PEG) and poly(dimethylsiloxane) (PDMS) mixture. The proposed needle device was applied for the determination of volatile compounds in lavender and lavandin essential oils by gas chromatography. Fundamental parameters such as needle design, conditions of extraction and desorption were optimized along with the validation of the extraction and desorption efficiency. The optimal conditions were 30 min extraction at $50^{\circ}C$ and 2 min desorption at $240^{\circ}C$. The calibration curves showed good linearity with the suitable values of the coefficients of determination ($r^2$) greater than 0.99. The limits of detection for linalyl acetate, ${\beta}$-caryophyllene, linalool and (+)-limonene were 7.15, 9.04, 10.79 and 22.26 ng, respectively. Analytical recoveries were acceptable in the test samples, varying from 86.7% to 108.0%. The values of relative standard deviations for run to run showed range less than 0.9% while 3.9% through 7.2% for needle to needle. The proposed PEG-PDMS coating could be more suitable than PDMS coating to extract particular polar groups such as alcohols.

• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.795-799
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• 2007

The bulk properties of poly(γ-benzyl-L-glutamate)-poly(ethylene glycol), PBLG-PEO, diblock copolymer were investigated. The helical transition from 7/2 to 13/5 for pure PBLG was at 120 oC while those of GE-1 and GE-2, which contain flexible PEO block 40 wt% and 60 wt% respectively, were shown at 135℃ on DSC experiments. FT-IR and XRD experiments were shown that the diblock copolymers maintained their α-helical structure in the temperature range between 25℃ and 175℃. Increasing relative size of coil part resulted in the increase of intermolecular packing distances. Due to well-maintained helical structure, lyotropic LC phases were observed for the PBLG-PEO block copolymer by the polarized optical microscope (POM). Especially, GE-3 copolymer, which has 12.5 wt% PEO contents, showed the smectic C phase. The competition of favorable aggregation energy between rod-rod and coil-coil, and unfavorable aggregation energy of rod-coil give rise to change the supramolecular structure in mixed solvent.

• Macromolecular Research
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• 제13권4호
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• pp.344-351
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• 2005

pH-sensitive block copolymers were synthesized by coupling reaction of sulfamethazine and amphiphilic diblock copolymer, and their micellization-demicellization behavior was investigated. Sulfamethazine (SM), a derivative of sulfonamide, was introduced as a pH responsive moiety while methoxy poly(ethylene glycol)poly(D,L-lactide) (MPEG-PDLLA) and methoxy poly(ethylene glycol)-poly($D,L-lactide-co-{\varepsilon}-caprolactone$) (MPEG-PCLA) were used as biodegradable amphiphilic diblock copolymers. After the sulfamethazine was carboxylated by the reaction with succinic anhydride, the diblock copolymer was conjugated with sulfamethazine by coupling reaction in the presence of DCC. The critical micelle concentration (CMC) and mean diameter of the micelles were examined at various pH conditions through fluorescence spectroscopy, dynamic light scattering and transmission electron microscopy. For MPEG-PDLLA-SM and MPEG-PCLA-SM solutions, the pH-dependent micellization-demicellization was achieved within a narrow pH band, which was not observed in the MPEG-PDLLA and MPEG-PCLA solutions. The micelle showed a spherical morphology and had a very narrow size distribution. This pH-sensitive block copolymer shows potential as a site-targeted drug carrier.

• Macromolecular Research
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• 제16권3호
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• pp.231-237
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• 2008

Biodegradable poly($\varepsilon$-caprolactone-co-L-lactide)-b-poly(ethylene glycol) (PCLA-b-PEG) copolymers were synthesized via solution polymerization by varying the feed composition of $\varepsilon$-caprolactone ($\varepsilon$-CL) and L-lactide (LLA) ($\varepsilon$-CL: LLA= 10:0, 7:3, 5:5, 3:7, 0: 10). The feed ratio based on weight is in accordance with the copolymer composition except for the case of $\varepsilon$-CL: LLA=3:7 (C3L7), which was verified by $^1H$-NMR. Two different approaches were used for the exceptional case, which is an extension of the reaction time or the sequential introduction of the monomer. A copolymer composition of $\varepsilon$-CL: LLA=3:7 could be obtained in either case. The chemical microstructure of PCLA-b-PEG was determined using the $^{13}C$-NMR spectra and the effect of the sequential structure on the thermal properties and crystallinity were examined. Despite the same composition ratio of the copolymer, the microstructure can differ according to the reaction conditions.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1999년도 가을 한국섬유공학회 학술발표회 논문집(Proceedings of the Korean Textile Conference)
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• pp.13-16
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• 1999

• 멤브레인
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• 제20권1호
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• pp.13-20
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• 2010

염료감응형 태양전지를 위한 고분자 전해질막을 제조하였다. 고분자물질로는 Poly(ethylene oxide) (PEO)를 사용하였으며, 가소제로서 poly(ethylene glycol) (PEG)를 첨가하였고, 전해질염 및 $I^-/{I_3}^-$의 공급원으로서 KI 및 $I_2$를 첨가하여 고분자 전해질막을 제조하였으며, 이와 같은 고분자 전해질막을 바탕으로 염료감응형 태양전지를 제조하였다. 고분자 전해질 내의 가소제로서의 PEG 함량은 0%에서 85%의 범위로 변화하였다. 이러한 PEG 함량 전 구간에서 고분자 전해질막은 그 형태를 자체적으로 유지하는(self supporting) 완벽한 고체 전해질막의 형태로 제조되었다. PEG 함량이 증가하면서 전해질막을 통한 이온전도도와 ${I_3}^-$ 이온의 확산도계수는 증가하였다. 염료감응형 태양전지에 있어서는 고분자 전해질막 내의 PEG 함량이 증가하면서 그 효율이 증가함을 볼 수 있었다.

• Macromolecular Research
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• 제17권10호
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• pp.729-733
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• 2009

Solution casting films of sulfonated poly[styrene-b-(ethylene-r-butylene)-b-styrene] copolymer (sSEBS)-based composite membranes that contained different amounts of organic, nanorod-shaped polyrotaxane were annealed at various temperatures for 1 h. The films' properties were characterized with respect to their use as polymer electrolyte membranes in direct methanol fuel cells (DMFCs). Different aspect ratios of polyrotaxane were prepared using the inclusion-complex reaction between $\alpha$-cyclodextrin and poly(ethylene glycol). The presence of the organic polyrotaxane inside the membrane changed the morphology during the membrane preparation and reduced the transport of methanol. The conductivity and methanol permeability of the composite membranes decreased with increasing polyrotaxane content, while the annealing temperature increased. All of the sSEBS-based, polyrotaxane composite membranes annealed at $140^{\circ}C$ showed a higher selectivity parameter, suggesting their potential usage for DMFCs.

• 한국염색가공학회지
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• 제15권4호
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• pp.51-56
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• 2003

Poly(ethylene terephthalate) (PET) fabrics were dyed with a series of ethoxylated alkylaminoanthraquinone dyes synthesized by the reaction of 1-aminoanthraquinone with poly(ethylene glycol) via a series of methylene spacer, and their hydrophilicity and durability to laundering were investigated. The results obtained are as follows: 1) Ethoxylated alkylaminoanthraquinone were successfully exhausted on PET fabric without any aid of chemical auxiliary. 2) The wettability of the dyed PET fabric was increased with the length of ethoxylate chain. 3) The durability of the wettability was good enough as to maintain the initial wettability even after 30 repeated launderings.

• 한국염색가공학회지
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• 제15권3호
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• pp.185-191
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• 2003

Surface modification of poly(ethylene terephthalate) (PEI) films by treatment with ethoxylated alkylaminoanthraquinoes which was synthesized by the reaction of 1-aminoanthraquinone with poly(ethylene glycol) via a series of methylene spacer were investigated. The synthesized ethoxylated alkylaminoanthraquinones showed definite cloud point as in nonionic surfactants, and the adsorption of the compounds on PET increased near the cloud point. At same temperature the adsorption increased with the length of methylene spacer; hexyl-octyl-, and decyl-. The adsorption was limited to the extreme surface of PET film, which made the surface of PET film hydrophillic by reducing water contact angle.