• Title/Summary/Keyword: Hydrophobicity

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Synthesis of Red Disperse Dyes with Various Diazo Components and Coloration of Unmodified Pure Polypropylene Fibers

  • Kim, Tae-Kyeong;Jang, Kyung-Jin;Jeon, Seon-Hee
    • Textile Coloration and Finishing
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    • v.22 no.1
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    • pp.1-7
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    • 2010
  • The five new red disperse dyes for unmodified pure polypropylene fibers were synthesized. As a coupling component, a di-n-hexyl substituent was used in common, while various substituents were used for the diazo component. The dye having electron donating group at diazo component showed hypsochromic shift compared to the unsubstituted dye, while the dyes having electron withdrawing groups showed bathochromic shift. Owing to their extreme hydrophobicity caused by the di-n-hexyl substituent, all dyes exhibited very high affinity toward pure polypropylene fibers. Fastness to washing was very good for all dyes and fastness to light was good except two purplish red dyes.

Wettability control in C-SiOx film formed by plasma polymerization of HMDSO/$O_2$ mixture

  • Kim, Seong-Jin;Lee, Kwang-Ryeol;Moon, Myoung-Woon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.328-328
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    • 2011
  • Wetting phenomena have been heavily studied for industrial and academic researches especially tuning the wettability between hydrophilicity and hydrophobicity. Wicking through the surface texture is shown on superhydrophilic surface while rolling (or dewetting) on the patterns of superhydrophobic surface. These wetting phenomena are known to be affected by surface wettability determined with physical surface patterns as well as chemical composition of surface layer. In this research, we introduce a method to control the wettability of a thin C-SiOx film from hydrophobic to hydrophilic using a mixture gas of HMDSO/$O_2$ by plasma polymerization with rf-CVD (radio frequency-Chemical Vapor Deposition). Wettability was finely controlled by changing the ratio of HMDSO/$O_2$. Hydrophilicity increased as the ratio decreased, while hydrophobicity was enhanced by the ratio. Moreover, fine control from superhydrophilicity to superhydrophobicity was achieved by C-SiOx coating on the Si wafer with prepatterns of submicron-sized pillar array formed by $CF_4$ plasma etching.

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A Study on Ageing Characteristics of RTV Silicone Coating Materials by Corona Discharge (RTV 실리콘 코팅재의 코로나 방전 열화 특성)

  • 한세원;한동희;조한구
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.8
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    • pp.359-364
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    • 2003
  • Ageing characteristics of RTV coating materials by corona discharge have been studied. The hydrophobicity recovery of RTV coating materials with 300${\mu}{\textrm}{m}$ thickness was identical with a bulk silicone materials. The RTV coating materials hydrophobicity has been almost lost when its were discharged during 40 seconds by corona discharge of 10㎸, and recovered after about 45 hours. The resistivity of RTV coating materials has not been recovered after 45 hours, though after 80 hours the initiation resistivity value has been recovered up to 95%. There was no critical change of compounds(such as Si and Al) on RTV surfaces by the corona discharge treatment until 100 seconds. In the test of arc erosion, it was seen that the coating sample with silicone rubber as a base material have more longer burn-out time than other samples with FRP or glass base.

UV Aging on EPDM rubber for use in polymer Insulators (폴리머 애자용 EPDM 고무의 자외선 열화특성)

  • Youn, Bok-Hee;Lee, Sang-Yong;An, Jong-Sik;Huh, Chang-Su
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.62-65
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    • 2001
  • The effects of accelerated UV radiation on EPDM used for a polymeric insulator were investigated by contact angle, surface voltage decay after corona charging, SEM-EDX, ATR-FTIR and XPS. EPDM occurs as loss of hydrophobicity by UV treatment, which followed by surface cracking and chalking. The surface voltage decay on UV-treated EPDM show that the shorter decay time corresponded to the treated samples with a longer UV exposure time. The surface oxygen and aluminum content were found to increase and carbon decrease, as is observed in EDX analysis. The ATR-FTIR and XPS indicated that C-C and C-H groups decreased and the highly oxidized carbon bonds such as C-O, C=O and O-C=O increase with time. Also, the effects of surface charges on hydrophobicity based on our results is discussed.

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Study on UV degradation in Polymeric Insulating Materials for Use in Outdoor Insulators by Corona-Charging (코로나 대전을 통한 옥외용 고분자 절연재료의 자외선 열화특성 연구)

  • Youn, Bok-Hee;An, Jong-Sik;Lee, Sang-Yong;Huh, Chang-Su
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.106-109
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    • 2001
  • In this paper, we have investigated the degradation of shed materials of outdoor insulators by UV-radiation by using corona-charging and XPS analysis. The accumulated charges on polymeric surface having intrinsic hydrophobic property have a negative impact on retaining its hydrophobicity. Therefore, shorter decay times of surface charges are preferred. The surface voltage decay on UV-treated silicone rubber and EPDM show a different decay trend with UV treated time. From the XPS analysis, the oxidized groups of silica-like structure in silicone rubber increase with UV treatment time. For EPDM, the oxidized carbon groups of C=O, O=C-O increase as elapse of UV radiation time. These oxidized surface for each material have different electrostatic characteristics, so deposited charges may be expected to have different impacts on their surface hydrophobicity. The degradation mechanism based on our results is discussed.

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Estimation for Retention Factor of Isoflavones in Physico-Chemical Properties

  • Lee, Seung-Ki;Row, Kyung-Ho
    • Bulletin of the Korean Chemical Society
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    • v.24 no.9
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    • pp.1265-1268
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    • 2003
  • The estimation of retention factors by correlation equations with physico-chmical properties maybe helpful in chromatographic work. The physico-chemical properties were water solubility (S), hydrophobicity (P), total energy ($E_t$), connectivity index 1 ($^1{\chi}$), hydrophilic-lipophlic balance (x) and hydrophilic surface area (h) of isoflavones. The retention factors were experimentally measured by RP-HPLC. Especially, the empirical regulations of water solubility and hydrophobicity were expressed in a linear form. The equation between retention factors and various physico-chemical properties of isoflavones was suggested as $k = a_0 + a_1\;log S + a_2log\;P^Q + a_3(E_t) + a_4(^1{\chi}) + a_5(x) + a_6(h)$, and the correlation coefficients estimated were relatively higher than 0.95. The empirical equations might be successfully used for a prediction of the various chromatographic characteristics of substances, with a similar chemical structure.

The Diagnosis of Polymeric Insulation Materials for Outdoor in the Salt Fog (Salt fog 내에서 옥외용 고분자 절연물의 절연진단)

  • Moon, J.S.;Kim, J.H.;Lee, J.H.;Song, W.C.;Cho, H.G.;Yoo, Y.S.;Park, Y.G.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1569-1571
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    • 2000
  • The ageing process was checked by leakage current monitoring in Salt Fog Method. In order to monitor leakage current, DAS with 12-bit, 8-channel A/D converter was prepared. The monitored components of leakage current were averages of the rms and peak, max peak, cumulative charge, and the cumulative number of peak pulses. The acquired data were stored to the disc periodically. And, surface conductivity was measured to investigate loss of hydrophobicity. The results suggest that surface conductivity and leakage current are well corresponding to initial loss of hydrophobicity.

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Back-Extraction Processes of C.C.Lipase with Mediated AOT Reverse Micellar System

  • Lee, Sung-Sik;Kim, Bong-Gyu;Sung, Nak-Chang;Lee, Jong-Pal
    • Bulletin of the Korean Chemical Society
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    • v.25 no.6
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    • pp.873-877
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    • 2004
  • The relationship between the behaviors of c.c.lipase back-extraction and their percolation phenomena by using AOT reverse micellar systems (RVMS) has been studied by the addition of a small amount of additives to organic phase such as thiols and nonionic-surfactants focusing on micelle-micelle interactions. The values of ${\beta}_t$ defined by the variation of percolation processes and back-extraction behaviors of c.c.lipase have a good linear correlation. The hydrophobicity of additive molecules suppressing the cluster formation of reverse micelles (high values of ${\beta}_t$) improved the back-extraction behavior of c.c.lipase. The back-extraction fraction and its rate of c.c.clipase are increased with decreasing of the value of hydrophilic lipophilic balance (HLB) and increasing of the hydrophobicity per additive molecules added to reverse micellar systems (RVSM) in the same additives concentration.

Effect of Long-term Corona-discharge on RTV Silicone Rubber (장기 코로나 처리에 따른 RTV 실리콘 절연재료의 특성변화)

  • 연복희;안종식;허창수
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.266-269
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    • 2001
  • This paper investigated the aging characteristic under long-term corona discharge on loon temperature vulcanized silicone rubber, which has been using as a protective coating material for solving the contaminant problem. The applied electrical field is 10kV/cm ac and corona discharge treatment was applied on RTV silicone rubber sheet for maximum 250 hours. With the duration of corona discharge, the diffusible low molecular weight species increased, which was determined the usage of n-hexane extraction method. In addition, the contaminant layer was formed on the treated surface, and then measured the contact angle. We investigated the relation of contact angle and diffusible low molecular weight species. It is found that scissor of main chain PDMS and side chains (CH$_3$) and the generation of LMW species were occurred by a corona discharge. The improvement of hydrophobicity rate is thought due to the increase of diffusible LMW species.

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A Study on the Light Stimulus of Organic Thin Films (유기박막의 광 자격에 관한 연구)

  • 김성진;이경섭
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.283-286
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    • 2000
  • In this paper, generation form of displacement current was compared and measured induce monolayers which 8A5H with Pure azobenzene. Light response of two monolayers which compared and measured though they are the same isomer. The experimental results are as following; In case of ultraviolet($\lambda_1$) and visible($\lambda_2$) irradiation on 8A5H induce monolayers depositioned on board the peak of current was detected about 10[fA]. but light irradiation on pure azobenzene any particular reaction for detailed. This is the reason of hydrophobicity construct in molecule structures its molecule dynamic behaviour in cis and trans was not due to activated.

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