BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Ionomer Design Principles for  Ion-Conducting Energy Materials - P
 rofessor Ralph Colby\, Pennsylvania State University\, USA
DTSTART:20120511T130000Z
DTEND:20120511T140000Z
UID:TALK37977@talks.cam.ac.uk
CONTACT:Tracy Inman
DESCRIPTION:We synthesize single-ion conducting ionomers with low glass tr
 ansition temperatures to prepare ion conducting membranes for actuators an
 d lithium battery separators. We use dielectric spectroscopy to determine 
 the number density of conducting ions and their mobility from electrode po
 larization (using the 1953 Macdonald model) and the number density of ion 
 pairs from measured dielectric constant (using the 1936 Onsager model).  T
 his experimental work concludes that the number density of conducting ions
  is tiny\, and we discuss ways to boost that using more polar polymers wit
 h weak-binding anions attached to the chain.\nWe use ab initio quantum che
 mistry calculations at 0 K in vacuum to characterize ion interactions and 
 ion solvation by various functional groups on ion-containing polymers.  Si
 mple ideas for estimating the ion interactions and solvation at practical 
 temperatures and dielectric constants are presented that indicate the rank
  ordering observed at 0 K in vacuum should be preserved.  Hence\, such ab 
 initio calculations are useful for screening the plethora of combinations 
 of polymer-ion\, counterion and polar functional groups\, to decide which 
 are worthy of synthesis for new ionomers.  The results provide estimates o
 f parameters for a simple four-state model for counterions in ion-containi
 ng polymers: free ions\, isolated ion pairs\, triple ions and quadrupoles.
   We show some examples of how ab initio calculations can be used to under
 stand experimental observations of dielectric constant\, glass transition 
 temperature and conductivity of polymerized ionic liquids with either lith
 ium or ionic liquid counterions.  In particular\, recent calculations prov
 ide some important insight as to why poly(ethylene oxide) is able to raise
  the dielectric constant to boost ion transport.
LOCATION:Pippard Lecture Theatre\, Cavendish Laboratory
END:VEVENT
END:VCALENDAR