BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//RLASKEY//CALENDEROUS//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260914T142324Z
LAST-MODIFIED:20151030T142540Z
DTSTART:20151106T170000Z
DTEND:20151106T180000Z
UID:event1512@bu.edu
URL:http://physics.bu.edu/internal/events/show/1512
SUMMARY:Tubes\, Topology\, and Entangled Rings
DESCRIPTION:Featuring Scott Milner\n\nPart of the Biophysics/Condensed Matt
	er Seminar Series.\n\nLong polymer chains in concentrated solutions or dens
	e melts interpenetrate extensively. Polymer motion is severely restricted b
	y entanglement and topological constraints\, long understood in terms of a 
	confining tube. We show that a purely topological approach can be used to c
	ompute the entanglement length Ne by establishing a direct link to the stat
	istics of topological states in simulations of topologically equilibrated r
	ing polymers. We determine how Ne varies with solvent dilution and chain st
	iffness.  Another way to study entanglement is to use simulations to test t
	ube-based theory predictions for entangled chain dynamics; this has been do
	ne extensively for entangled linear chain melts.  This has been done extens
	ively with large-scale molecular dynamics simulations for entangled linear 
	chain melts.  One might suppose the dynamics of a self-entangled ring would
	 be uninteresting\, because of the absence of free ends and the permanent c
	onfinement of the chain to the tube.  In fact\, a ring trapped in a tube sh
	ould have four dynamical regimes\, just as for entangled linear chains:  fr
	ee Rouse motion below the entanglement strand Rouse time tau_e\, curvilinea
	r Rouse motion up to tau_R\, reptation up to tau_d\, stationary thereafter.
	  Because there are no end effects\, we can write analytical expressions fo
	r the monomer mean-square displacement versus time\, which can be compared 
	to simulations to determine tau_e and Ne.
LOCATION:SCI 352\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
END:VEVENT
END:VCALENDAR