• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.129-129
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• 2010

The conjugated oligomers with rigid and fused-ring structures are of interest for the solution-processable organic thin film transistors (OTFTs) due to their well defined structure and high purity. In this study, alkyl substituted benzothiophene based oligomers were synthesized by a novel route, the key point of which is the acid-induced intermolecular cyclization reaction of aromatic methyl sulfoxides, and were confirmed by $^1H$-NMR and FT-IR studies. The obtained oligomers showed the good solubility in common organic solvents such as hexane, chloroform, and dimethylchloride at room-temperature, which is due to the introduced alkyl chain. The physical and optical properties of the oligomers were studied using differential scanning scalorimetry (DSC), cyclic-voltammetry (CV), UV-visible and PL spectra studies. Solution processed OTFT device based on synthesized oligomers show a high hole mobility of up to $0.01\;cm^2V^{-1}s^{-1}$, $I_{on}/I_{off}$ of $10^5$ and threshold voltage of -14V.

• Bulletin of the Korean Chemical Society
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• v.25 no.2
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• pp.280-284
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• 2004

The optimum conditions for the most effective precipitate of surfactant complex of sodium alkylsulfate with cetylpyridinium chloride were studied in the aqueous solution. The parameters such as the alkyl chain length of anionic surfactants, molar ratio of two surfactants, temperature and the concentration of added NaCl in the aqueous solution were correlatively studied for the productivity of the precipitate formation. By the productivity, the optimum conditions to produce complex of anionic surfactant with cationic surfactant were the longer alkyl chain, equivalent molar ratio between anionic and cationic surfactants, 0 $^{\circ}C$ and 1.5 M NaCl.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3790-3794
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• 2013

Molecular dynamics simulations were performed to study the structure and stability of a nanoscale self-assembled monolayer (SAM) of alkanethiol on a gold (111) surface. The tilt angle and orientational order of the alkyl chains in the SAM island were examined by systematically varying the size of the island. The chain length dependence of the SAM island was examined by considering alkanethiols containing 12, 16, 20, and 24 carbon atoms. The minimum diameter of SAM islands made from 1-tetracosanethiol, 1-ecosanethiol, 1-hexadecanethiol and 1-dodecanethiol were 2.29, 1.9, 4.7 and 4.76 nm, respectively. These set the ultimate resolution that can be patterned by soft nanolithography. As the length of alkanethiol increases, the SAM islands became more ordered in both orientation and conformation of the alkyl chains.

• Journal of Information Display
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• v.11 no.4
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• pp.144-148
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• 2010

In this paper, vertically aligned (VA) liquid crystal (LC) modes were investigated using the alkyl chain ordering effect of self-assembled monolayers (SAMs) prepared on the anisotropic inorganic surface. On the anisotropic surface prepared through oblique ion beam irradiations, the SAM molecules are adsorbed, producing macroscopic alkyl chain ordering, which can determine the pretilt direction of the vertically aligned LC molecules through the intermolecular interactions on the surface.

• Journal of Photoscience
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• v.8 no.2
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• pp.75-77
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• 2001

The Grignard reaction of methyl pyropheophorbide-a (MPP-a) was performed to introduce lengthy alkyl chain for improving lipophilicity. After the introduction of alkyl chain to the both of carbonyls, peripheral aldehyde and cyclopentanone, the obtained diol 3 was subjected to dehydration to give monodehydrate product 4 selectively. The Qy band of prepared compounds were affected by the substituents on the Qy axis (N$\sub$21/-N$\sub$23/).

• Macromolecular Research
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• v.14 no.6
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• pp.630-633
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• 2006

In heterojunction photovoltaic devices of $ITO/TiO_2/poly$(3-alkylthiophene)/Au, the photo current was characterized at different temperatures for different alkyl chain lengths and regioregularities: regiorandom, regioregular poly(3-hexylthiophene), and regioregular poly(3-dodecylthiophene). The regioregularity and alkyl chain length affected the photovoltaic characteristics due to differences in hole-carrier transportation. The drift charge mobilities of these devices were analyzed by the space-charge-limited current theory using the relation between the dark current and the bias voltage. The photocurrent in the devices based on poly(3-alkylthiophene)s decreased rapidly below the temperature at which the drift charge mobility was $10^{-5}\;cm^2/V{\cdot}s$.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.199-205
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• 2016

We present the electrochemical performance of electric double layer capacitors (EDLCs) assembled with pyrrolidinium (Pyr)-based ionic liquid electrolytes at 55 ℃. Cations with various alkyl chain lengths were employed in Pyr-based ionic liquids to investigate the effect of cation structure on the cycling stability of EDLCs. The EDLCs exhibited initial specific capacitances ranging from 122.4 to 131.6 F g⁻¹ based on activated carbon material at 55 ℃. Cycling data and XPS results demonstrate that Pyr-based ionic liquid with longer alkyl chain is more effective for enhancing the cycling stability of EDLC by suppressing the reductive decomposition of pyrrolidinium cations during cycling at high temperatures.

• Macromolecular Research
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• v.16 no.7
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• pp.596-603
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• 2008

To improve the mechanical properties, dimensional stability and blood compatibility, the biomedical material $Pellethene^{(R)}$ was blended with multiblock polyurethane (MPU) containing phospopholipid/long alkyl chain (C-18) at the various MPU contents and crosslinked using dicumyl peroxide as a crosslinking agent. The maximum MPU content for stable $Pellethene^{(R)}$/MPU blended films was approximately 30 wt%. The optimum crosslinking agent content and crosslinking time with respect to the mechanical properties were 4 wt% and 3 h, respectively. The mechanical properties (tensile strength and elongation at break) and water absorption of the crosslinked blend film increased with increasing MPU content. The test of platelet adhesion on the surfaces of the crosslinked blend film showed a decrease in the level of platelet adhesion from 70% to 6% with increasing MPU content from 0 to 30 wt%. These results suggest that the crosslinked $Pellethene^{(R)}$/MPU-30 (MPU content: 30 wt%) sample has strong potential as a novel material for blood compatible material applications.

• Macromolecular Research
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• v.16 no.7
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• pp.631-636
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• 2008

The intrinsic viscosities were determined for poly(DL-lactic acid) (PDLLA) solutions in 1,2-dialkyl phthalate at temperatures ranging from 30 to $60^{\circ}C$. A series of dialkyl phthalate, in which the alkyl group was changed from methyl to propyl, was used as the solvent to control the solvent quality systematically. The intrinsic viscosity of the PDLLA solution was higher in the better quality solvent, with a higher molecular weight of PDLLA, and at lower temperatures. The unperturbed dimensions of the PDLLA molecule and polymer-solvent interaction parameter of PDLLA in dialkyl phthalate were deduced using extrapolation methods based on the temperature-dependent intrinsic viscosities. Slight shrinkage in the unperturbed chain dimension was observed, which resulted from a change in polymer conformation with temperature. It was also observed that the polymer-solvent interaction became more favorable with the dialkyl phthalate containing a shorter alkyl chain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.792-796
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• 1993

The synthesis alcohol-oxidase[EC 1.1.3.13] was investigated in the yeasts, Candida boidinii CBS 8106 and C. boidinii CBS 2428, during growth on different carbon sources. Alcohol-oxidase was undetectable in all strains submitted to the test in the mineral salts medium containing 1.0% glucose, but its production was rapidly increased when the carbon source was changed glucose to 1.0% methanol after 24hrs of incubation. When cells were grown on the various carbon sources (glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), the alcohol-oxidase activity was undetected. These carbon sources together with methanol yielded far better synthesis of alcohol-oxidase than in the case of carbon sources alone. Alcohol-oxidase was active towards alcohol of shorter alkyl-chain length than C5 and unsaturated alcohols. Its affinity for these alcohols decreased with the increasing length of the alkyl-chain. The apparent Km values for the methanol of Candida boidinii CBS 8106 and C. boidinii CBS 2428 were 1.96 and 1.21, respestively.