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Ethylene Glycol-Water 혼합용매에서 Micelle 형성
李鍾萬,睦丁均 성신여자대학교 기초과학연구소 1984 基礎科學硏究誌 Vol.1 No.-
계면활성제 분자 또는 이온의 집합체인 micelle 은 순수 소수성 결합만으로 이루어진 모형계이다. 소수성 결합은 비극성기들이 수소결합된 물 구조에 영향을 줌으로써 생기는 간접적인 인력이므로 물 용매만이 갖는 특성이 아니고 일반적으로 solvophobic interaction를 갖는 용매의 특성이다. 본 연구에서는 물과 성질이 유사한 비수용성 극성용매인 ethylene glycol를 선택하여 그 용매내에서 dodecyl pyridinium bromide(DPB)의 계면활성을 조사하기 위하여 micelle형성 임계농도(cmc)와, ethylene glycol과 물의 혼합용매내에서 온도변화에 따른 cmc를 표면장력을 측정하여 조사한 결과, cmc 값은 순수한 ethylene glycol용매내에서 가장 크게 나타났으며 물과의 혼합용매내에서는 물이 첨가되는 비율이 높을수록 감소하는 현상을 나타냈다. 이러한 사실로부터 ethylene glycol의 solvophobic interaction이 물보다 작음을 알 수 있었다. 또한 표면장력 측정방법은 계면활성제 용액내에서 계면활성제 분자의 표면배향평형에 있어 문제점을 갖는 ring method를 보완한 방법을 사용한 결과, 재현성이 좋고 정확한 표면장력을 측정할 수 있는 방법임을 알았다. The micelle, which is made by molecules or ions of surfactant, is a purely hydrophobic bonding model system. Hydrophobic bonding is the outcome of indirect attraction by affecting non-polar group on hydrogen-bonded water structure; that is not only characteristics of water but also generally that of solvent giving rise to solvophobic interaction. Ethylene glycol as non-aqueous polar solvent similar to water in properties has been chosen. To investigate surface activity of dodecyl pyridinium bromide(DPB) in the ethylene glycol and ethylene glycol-water mixed solvent, the surface tension of its solution has been measured at 35℃ and 45℃. The critical micelle concentration(cmc) determined by surface tension method has the highest value in poor ethylene glycol.In the ethylene glycol-water mixed solvent, the more the portion of water has increased, the more cmc has decreased. After all. solvophobic interaction of ethylene glycol has acted much less than that of water. And the measurement of surface tension has used a modified ring method which has the problem in surface orientation equilibrium of surfactant molecule. In consequence, we have known that the new modified method has the good reproducibility and a precise value of the surface tension.
睦廷均,車岷煥 서울市立大學校 1990 論文集 Vol.24 No.-
To obtain a more simplified method for analyzing the dewatering mechanism of particulate beds in gravitational field the conventional equation for flow in capillaries is empirically modified in view of the existence of filmwise liquid. A simple equation for prediction the average saturation vs, the time is presented, by considering the beds as an assembleage of circular monosize capillaries determined from packed bed porosity and particle size. The progress of dewatering process can be followed using local saturation data measured throughout depth of the bed by means of the electrical conductivity, and good agreement has generally been found between computed and experimental data. It is obtained in terms of the average saturation and Zeitz number(Nzt). ??