BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Critical depletion - Prof Roberto Piazza (Politecnico di Milano)
DTSTART:20100521T110000Z
DTEND:20100521T120000Z
UID:TALK24593@talks.cam.ac.uk
CONTACT:Dr Mark Miller
DESCRIPTION:The investigation of the equilibrium and nonequilibrium proper
 ties of dispersion of particles in the colloidal\nsize range has proved to
  be a powerful tool to test basic theoretical models in statistical mechan
 ics and\ncondensed matter physics.  Two distinct and apparently unrelated 
 topics are of current interest for colloid science: depletion interactions
  and colloid phase separation in critical liquid mixtures. The former\, st
 emming from the addition to a colloidal suspension of high-molecular weigh
 t solutes\, yield significant clues on many distinctive phase-separation a
 nd gelation effects\, including some of biological relevance\, whereas the
  latter bears a strict relation with the so-called critical Casimir effect
 \, predicted a long ago by Fisher and De Gennes\, and quantitatively inves
 tigated for colloids very recently.  By exploiting as depletion agent a su
 rfactant showing a critical demixing point with the solvent\, I will show 
 that depletion forces merge continuously into critical Casimir effects. Cl
 ose to the depletant critical point\, the phase behavior is solely dictate
 d by the diverging correlation length\, and shows a distinctive scaling be
 havior.  I shall also briefly present a general theoretical approach to de
 pletion effect in correlated systems\, developed by A. Parola and J. Colom
 bo\, that rigorously justifies the observed continuity between simple depl
 etion and critical Casimir effects\, and semi-quantitatively accounts for 
 the observed trends in a simple model system.
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
END:VEVENT
END:VCALENDAR