• 방사성폐기물학회지
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• 제15권1호
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• pp.27-34
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• 2017

본 연구에서는 오염된 점토 내 Cs을 제거하기 위하여, 계면활성제의 소수성 알킬사슬의 길이에 따른 Cs의 탈착특성을 연구하였다. 양이온성 계면활성제로 Alkyl trimethyl ammonium bromide를 사용하였고, 소수성 알킬사슬은 octyl-, dodecyl-, cetyl- 으로 변화시켰다. 소수성 알킬사슬이 길어질수록 montmorillonite 내 계면활성제의 흡착량이 증가하였고, 계면활성제의 층간 흡착으로 층간거리가 증가하는 것으로 나타났다. Cs의 탈착률도 알킬사슬의 길이가 증가함에 따라 향상되었고 cetyl 그룹을 갖는 양이온성 계면활성제는 최대 $992{\pm}2.9%$의 Cs 제거율을 나타냈다.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1009-1011
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• 2009

Nano-structured conducting polypyrroles were synthesized in the ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium family with tetrachloroferrate as an anion ($C_n\;mim\;[FeCl_4]\;with\;n\;=\;4,\;8,\;and\;12$). The polypyrrole nanostructures synthesized in ILs were formed as spherical shapes. For ionic liquids with alkyl side chain length $C_4,\;C_4\;mim\;[FeCl_4]$, the size of particles was ranged around 60-nm with a relatively narrow size distribution. As the length of alkyl chain increases, the particle sizes become larger and their distributions become wider. The self-assembled local structures in the solvent ionic liquids are likely to serve as templates of highly organized nano-structured polymers. The length of the alkyl chain in ionic liquids seems to affect these local structures.

• 한국응용과학기술학회지
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• 제32권1호
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• pp.40-47
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• 2015

Single-walled carbon nanotubes (SWNTs) was modified with various length of linear alkyl chains and passivated to form dielectric filler. The modified SWNTs embedded into epoxy matrix to fabricate a flexible composite with high dielectric constant. The dielectric behavior of the composite was significantly changed with various alkyl chain length(n) of pyrene. The dielectric constant of the epoxy/SWNTs composite significantly increased with respect to increase in length of alkyl chain at the frequency range from 10 to 105Hz (n=12and18).We also found that the passivated epoxy/SWNTs composite with high dielectric constant presented low dielectric loss. The resulted dielectric performances corresponded to de-bundling of nanotubes and their distribution behavior in the matrix in terms of tail length of alkyl pyrene in the passivation layer.

• 한국응용과학기술학회지
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• 제33권3호
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• pp.428-434
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• 2016

본 연구에서는 알킬체인의 길이가 서로 다른 benzyltrialkylammonium chloride계 화합물을 합성하여 리포좀 제조에 응용하였다. 제조된 리포좀의 평균 입도분포, 제타전위, 방출거동 및 항균성을 조사하였으며, 사슬 길이에 따른 특성을 비교하였다. 리포좀의 평균 입도는 120~140 nm의 크기분포를 가졌으며 소수성 사슬의 길이가 증가할수록 큰 입자크기를 가졌다. 리포좀 용액의 제타전위는 양이온성 계면활성제인 benzyltrialkylammonium chloride를 첨가함에 따라 +80~90 mV의 값을 가지며 향상된 분산 안정성을 보였다. 방출거동에서는 사슬 길이에 따라 방출 속도를 조절할 수 있었으며 긴 사슬의 계면활성제를 첨가한 리포좀은 증가된 서방형 방출특성을 보였다. 또한, 리포좀의 포집효율은 25.9~27.5% 이었다.

• Entomological Research
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• 제48권5호
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• pp.448-452
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• 2018

The aggregation pheromone of Monochamus (Coleoptera: Cerambycidae) beetles, 2-(undecyloxy) ethanol (hereafter referred to as monochamol), has gained considerable attention because of its usefulness in monitoring and population control of pine sawyer beetles. The hydroxyether structural motif is conserved in pheromones of the subfamily Lamiinae of the Cerambycidae. In this study, we investigated the effects of C10- and C12-chain length alkyl analogs of monochamol, 2-(decyloxy) ethanol and 2-(dodecyloxy) ethanol, on attracting M. saltuairus in Andong, Gyeongsangbuk-do, Korea. The C10 and C12 analogs attracted M. saltuarius when used in combination with ${\alpha}$-pinene and ethanol, but the responses of these alkyl chain analogs were lower than those of monochamol. Furthermore, the addition of either C10 or C12 analog to the use of monochamol with ${\alpha}$-pinene and ethanol had no effect on attraction of M. saltuarius, indicating high sensitivity of M. saltuarius to monochanol. Taken together, the results of this study suggest that chemical communication within a Monochamus species depends not only on monochamol, but also on other semiochemicals.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.361-368
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• 2018

We investigated the interfacial properties of fluorocarbon self-assembled monolayers (FC-SAMs) with different alkyl chain lengths. It was found that the substrate characteristics were changed rapidly with the fabrication time and temperature of the SAM. FC-3SAM, which has the shortest alkyl chain in this study, showed a contact angle of $54.1^{\circ}$ when it was fabricated in an electric oven at $60^{\circ}C$ for the first minute. The FC-3SAM showed a contact angle of up to $76.9^{\circ}$ when it was fabricated in an electric oven at the same temperature condition for 180 minutes. FC-10SAM, which has the longest alkyl chain in this study, showed a contact angle of $64.7^{\circ}$ when it was fabricated at a temperature condition of $60^{\circ}C$ for 1 minute, and a contact angle of $98.7^{\circ}C$ at a temperature condition of $60^{\circ}C$ for 180 minutes. It was found that the FC-10SAM shows an increased contact angle and hydrophobic properties due to a well-aligned molecular structure resulting from a strong van der Waals force. In contrast, the FC-3SAM shows a small contact angle due to the intermolecular disorder resulting from a weak van der Waals force. The average roughness of FC-SAMs was investigated using AFM. The surface roughness of FC-SAMs, which verifies the results of contact angle, was confirmed. At a fabrication time of 120 minutes, the FC-10SAM showed an improvement in average roughness by 62% compared to that of FC-3SAM due to its good alignment.

• Bulletin of the Korean Chemical Society
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• 제19권10호
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• pp.1047-1054
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• 1998

We present the results of molecular dynamics simulations for three different systems of bilayers of long-chain alkyl thiol [S(CH2)15CH3] molecules on an solid-solid interface using the extended collapsed atom model for the chain-molecule. It is found that there exist two possible transitions: a continuous transition characterized by a change in molecular interaction between sites of different chain molecules with increasing area per molecule and a sudden transition from an ordered lattice-like state to a liquid-like state due to the lack of interactions between sites of chain molecules on different surfaces with increasing distance between two solid surfaces. The third system displays a smooth change in probability distribution characterized by the increment of gauche structure in the near-tail part of the chain with increasing area per molecule. The analyses of energetic results and chain conformation results demonstrate the characteristic change of chain structure of each system.

• 한국전기전자재료학회논문지
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• 제18권10호
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• pp.924-928
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• 2005

We synthesized the two types of photoalignment material of high thermal resistance with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the two types of photopolymer surface can be obtained. The Voltage-transmittance (V-T) curve in the photoaligned TN cell with UV exposure was different from two type. The response time of photoaligned TN cell was measured about 21 ms in two alkyl chain and about 15 ms in four alkyl chain.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1453-1455
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• 1996

The odd-even effect of the alkyl chain length of rubbed polyimide Langmuir-Blodgett (LB) surfaces on the extrapolation length of 5CB has been successfully evaluated for the first time by measuring polar anchoring strength. The extrapolation length of 5CB for rubbed PI-LB surfaces with even-numbers is small compared with odd-numbers for alkyl chain lengths of greater than 7 carbons. The extrapolation length of 5CB on rubbed PI-LB surfaces with odd-numbers increases gradually as the temperature increases but tends to diverge near the clearing temperature (Tc=$35.3^{\circ}C$). The extrapolation length diverges because of rapidly decreasing surface order near $T_c$. We suggest that the polar anchoring strength on rubbed PI-LB surfaces with even-number is strong because of relatively high surface ordering caused by more crystalline surfaces. Finally, we conclude that the odd-even effects of the polar anchoring strength in NLCs are strongly related to the character of the polymer and observed clearly for long alkyl chain lengths.

• 통합자연과학논문집
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• 제1권2호
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• pp.76-78
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• 2008

A series of the long-chain iron(II) alkylsulfonate hydrates were synthesized via self-assembly of surfactant alkyl chains in aqueous medium. Reaction of iron(II) salts with n-alkylsulfonate yields lamellar $Fe(CnH2n+1SO3)2{\cdot}4H_2O$. These compounds show a layered structure, as determined by XRD, consisting of alternating organic alkylsulfonate layers and inorganic iron(II) hydrate layers, with interlayer distances of upto 3.2 nm. This lamellar structure may be attributed to the amphiphilic nature of the surfactants, mediating the coordination and H-bionding interactions, and the hydrophobic alkyl chains. An alkyl chain packing of present system are differ from those of similar Cu(II) series, which are attributed from the size of hydrated metal(II) ions.