Spectrum Analysis of Thermally Excited Capillary Wave Detected by Laser-Light Scattering Method and Measurements of Interfacial Concentration of Active Species at Liquid-Liquid Interface

Research Project

Project/Area Number	62550709
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	化学工学
Research Institution	Himeji Institute of Technology
Principal Investigator	KANKI Tatsuo Department of Chemical Engineering, Faculty of Engineering, 工学部, 教授 (80047620)
Co-Investigator(Kenkyū-buntansha)	ASANO Tsuyoshi Department of Chemical Engineering, Faculty of Engineering, 工学部, 助手 (70047596)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥1,700,000 (Direct Cost: ¥1,700,000) Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1987: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	Capillary Wave / Interfacial Concentration / Laser-Light Scattering / 抽出 / 界面張力
Research Abstract	Laser-light scattering technique was applied to detect the thermally excited capillary wave at liquid-liquid interface, aiming at establishing an in-situ method measuring the interfacial concentration of chemical species such as surface active agents. In detecting the wave, light scattered by the wave at the interface was superimposed coherently with a reference beam as a local oscilator and its signal was amplified by superheterodyne. Signals of the wave were recorded by a wave analyzer either as a Fourie spectra or as a self-correlation function in real time. Noise waves under 1kHz were cut off through a high pass filter. In both cases, experiments were made in a variety of conditions by changing intensity of the laser beam ranging from 40 to 150mw and by attenuating the intensity of the reference beam down to 1/51200 by several ND filters. In consequence, the method of taking a correlation function was found to be superior to that of taking spectra for detecting the capillary wave. For water-n-heptan and water-benzen systems at 25 C, it was found that a wave of wave-number 51600[1/m] with frequency 3447hz and damping coefficient 2480[1/sec] and that with 3875hz and 1920[1/sec] exist at corresponding interfaces. Data analysis for determining the interfacial tension is now under process. Although "estimation of interfacial concentration of active species" planed as a main object of this study is left as an open problem, technical knowledge aquired here will be useful in developing the present method for direct measurements of the interfacial concentration of active species in multi-phase solution systems. Further investigation is now under schedule.