• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.1
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• pp.15-22
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• 2015

Poly(ethylene glycol) end-capped with pentafluorophenyl group(s) in ABA (FP-PEG-FP) and AB (mPEG-FP) types were prepared. Even though they were similar in composition, the lower critical solution temperature (LCST) of FP-PEG-FP was observed at $23^{\circ}C$, whereas that of mPEG-FP was observed at $65^{\circ}C$. To understand the large difference in solution behaviour of the two polymers, UV-VIS spectroscopy, microcalorimetry, 1H-NMR spectroscopy, and dynamic light scattering were used. FP-PEG-FP has two hydrophobic pentafluorophenyl groups at the ends of hydrophilic PEG (1000 Daltons), whereas mPEG-PF has a highly dynamic PEG (550 Daltons) block that are anchored to a hydrophobic pentafluorophenyl group. PF-PEG-PF not only has a smaller conformational degree of freedom than mPEG-PF but also can form extensive intermolecular aggregates, therefore, PF-PEG-PF exhibits a significantly lower LCST than mPEG-PF. This paper suggests that topological control is very important in designing a temperature-sensitive polymer.

• Macromolecular Research
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• v.14 no.1
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• pp.73-80
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• 2006

Sulfonated poly(ethylene glycol) (PEG-$SO_{3}$) grafted polyrotaxanes (PRx-PEG-$SO_{3}$) were prepared in order to utilize the unique properties of PEG-$SO_{3}$ and the supramolecular structure of PRx, in which PEG-$SO_{3}$ grafted $\alpha$-cyclodextrins ($\alpha$-CDs) were threaded onto PEG segments in a PEG-b-poly(propylene glycol) (PPG)-b-PEG triblock copolymer (Pluronic) chain capped with bulky end groups. Some of the PRx-PEG-$SO_{3}$ demonstrated a higher anticoagulant activity in case of PRx-PEG-$SO_{3}$ (P 105), and compared with the control they showed a lower fibrinogen adsorption in PRx-PEG-$SO_{3}$ (F68) and a higher binding affinity with fibroblast growth factor. The obtained results suggested that polyrotaxane incorporated with PEG-$SO_{3}$ may be applicable to the surface modification of clinically used polymers, especially for blood/cell compatible medical devices.

• Journal of the Korean Vacuum Society
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• v.14 no.3
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• pp.115-118
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• 2005

Structure analysis of model polymeric micelles, both for non-asosciative and associative cases is done by small angle neutron scattering method. Aggregation number of the hydrophobic cores and the lyotropic ordering transitions of aqueous solutions of poly(ethylene glycol)(PEG) (6 K or 10 K g/mol) end-capped with perfluoroalkyl groups $(-(CH_2)_2C_OnF_{2n+1}$ (n =6,8, or 10) are characterized. Aggregation number is mainly determined by the hydrophobe end group only, and is insensitive to polymer concentration or temperature. Also, there is no difference between non-associative micelles and associative micelles in terms of aggregation number. The model systems order into a BCC structure with increasing concentration.

• Journal of Adhesion and Interface
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• v.20 no.4
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• pp.140-145
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• 2019

In view of environmental considerations, the control of carbon dioxide (CO₂) and volatile organic compounds (VOCs) is one of important issues in the film and coating industries. Therefore, UV-curable system has been developed due to minimize emissions of VOCs and reduce CO₂ emission due to low energy consumption from fast curing. Also, biodegradable polymers economically are attractive because of environmental and economic concerns associated with huge waste plastics. In this study, UV-curable polyurethane acrylates with different compositions of biodegradable polylactide (PLA) diol and poly(ethylene glycol) as diols were synthesized and curing reaction of their end-capped acrylates was performed by UV exposure. Tensile strength, elongation, and Tg of the UV-cured polyurethane acrylates increased with PLA diol content in the diol while their hydrophilicity and thermal stability increased with the PEG content. These results indicated a property of UV-cured polyurethane acrylates could be controlled by environment-friendly diols.