理学部物理科学科セミナーのお知らせ(2010.10.06)

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日時 2010年10月06日(水)13:15〜
場所 京都産業大学理学部2号館3階 会議室
講演者 Dr. B. V. R. Tata(Indira Gandhi Centre for Atomic Research, India)
題目 「Phase Behaviour of Nanoparticle Dispersions and Nanogels」
対象 本学学生・教職員

講演概要

「Phase Behaviour of Nanoparticle Dispersions and Nanogels」

B. V. R. TATA
Light Scattering Studies Section, Condensed Matter Physics Division, Materials Science Group Indira Gandhi Centre for Atomic Research, Kalpakkam- 603 102

The assembly of nano or micron sized particles into ordered structures have gained wide spread recognition due to their importance in fundamental studies (as a model condensed matter system) as well as their practical applications in wide range of disciplines (viz. biosensors, optical devices, photonic crystals etc). One of the most fascinating aspects of nanoparticle dispersions is the appearance of long-range order. For instance, in the case of deionised suspensions of charged polystyrene nanospheres, the long-range order appears at very dilute conditions (volume fraction・ ~0.001) and for hard-sphere colloids the crystallization occurs at much higher values (・ ~ 0.5). In these dispersions particle size is fixed and temperature is not a controllable parameter to investigate the phase behaviour. Whereas aqueous dispersions of thermo-responsive poly (N-isopropylacrylamide) (PNIPAM) nanoparticles exhibit rich phase behaviour upon varying the temperature due to the variation in particle size as well as interparticle interaction. The talk deals with structural ordering, phase behaviour of charged nanoparticle dispersions and PNIPAM nanogel suspensions, as probed by light scattering and confocal laser scanning microscopy (CLSM) techniques. These charged nanoparticle dispersions as well as nanogel suspensions are shown to exhibit gas-like, liquid-like, crystalline and glass-like structural orders upon increasing np. The phase transitions such as gas-liquid, gas-solid, freezing/melting transitions observed in nanoparticle dispersions and in nanogels will be discussed. Understanding the phase behaviour of nanoparticle dispersions is crucial in preparing stable ordered structures and the talk highlights applications of these ordered nano-structures in the areas of sensors and devices.

  1. Tata & Jena, Solid State Communications 139, 562 (2006)
  2. “Statistical Physics of Complex fluids,” M. Tokuyama, E. R. Weeks, Y-H. Hwang and B. V. R. Tata, eds. S. Maruyama & M. Tokuyama (Tohoku University Press, Sendai, Japan - 2007)
  3. Tata et al. Solid State Comm., 147, 360 (2008)
  4. Brijitta, Tata & Kaliyappan, J. Nanoscience and Nanotechnology 9, 5323 (2009)
  5. Brijitta, Tata, Joshi & Kaliyappan, J. Chem. Phys. 131, 074904 (2009)
 
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