COLL 154 |
| Daisuke Mizuno, Yasuyuki Kimura, and Reinosuke Hayakawa. Department of Applied Physics, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan |
| We developed a novel method for measuring wide-band spectrum of dynamic electrophoretic mobility m*(w) of charged colloids. This method has been verified to provide rich information on 1)surface electrical properties of charged colloids, 2)local viscoelastic properties of solvent surrounding a well-characterized colloidal particle (microrheology). As a typical example of latter case, we report on the m*(w) of nanometer-sized particles dispersed in a dilute lamellar phase of a nonionic surfactant. Its frequency dispersion shows two relaxation processes around 1kHz(HF) and 1Hz(LF). It is quantitatively shown that these processes are caused by trapping of particles within the two characteristic local structures of lamellar phase. That is, interbilayer distance for HF and persistence length for LF, respectively. Our findings on the transport properties of particles in complex fluids may be applicable to the transport phenomena of proteins and secretions in biological system. |
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Colloidal and Molecular Electro-Optics
Division of Colloid and Surface Chemistry |