œ English œ Japanese Last Update : May 26, 2009

Research Area
We are developing "Nano-chemistry at liquid-liquid interfaces" and "New migration analysis of microparticles employing microscopically designed external fields".

1) Interfacial reaction: New measurement methods including a total internal reflection fluorescence/Raman spectrometry, a high-speed stirring method, a centrifugal liquid membrane method, a micro-sheath flow/laser fluorescence kinetic method and an interfacial SHG-CD method have been developed for the measurement of interfacial reactions. Our recent findings are the high lateral-viscosity of bio-membrane-mimic interface by single molecule diffusivity measurements, the generation of optical chirality due to the interfacial aggregation of achiral molecules and asymmetric molecular binding around the interfacial Ag-nanoparticles observed by SERS; all showed specific features of the chemistry at the liquid-liquid interface.
2) Migration analysis: We are inventing new migration analytical methods for the detection and sorting of microparticles with environmental and biological interests. Recently, we studied the periodic expansion-contraction migration of w/o microemulsion droplets by laser-photothermal-conversion photophoresis, the capillary dielectrophoresis of DNA, the electromagnetophoretic adsorption-force measurement and size sorting of latex, and the determination of magnetic susceptibility of single microparticles by magnetophoretic velocimetry. We have proposed the new concept of mass-spectrometry by the magnetophoretic velocimetry in ambient atmosphere.

Reference
  1. Interfacial nanochemistry in liquid-liquid extraction systems, H. Watarai, S. Tsukahara, H. Nagatani, A. Ohashi, Bull. Chem. Soc. Jpn, (Account) 76(8) 1471-1492 (2003).

  2. Measurement of circular dichroism spectra of liquid/liquid interface by centrifugal liquid membrane method, S.Wada, K.Fujiwara, H. Monjushiro, and H. Watarai, Anal. Sci., 20, 1489-1491(2004).

  3. Non]linear optical activity of porphyrin aggregate at the liquid/liquid interface, K. Fujiwara, H. Monjushiro and H. Watarai, Chem. Phys. Lett., 349-353 (2004).
  4. New principle of magnetophoretic velocity mass analysis, K.Watanabe, M. Suwa, and H. Watarai, Anal. Sci., 20, 1483-1485 (2004).

  5. Laser photophoretic migration with periodic expansion-contraction motion of photo-absorbing microemulsion droplets in water, M . Tanaka, H . Monjushiro, H . Watarai, Langmuir, 20, 10791-10797 (2004).