<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Resmi, R.</style></author><author><style face="normal" font="default" size="100%">Amrutha, S. R.</style></author><author><style face="normal" font="default" size="100%">Jayakannan, M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Control of molecular aggregation in symmetrically substituted pi-conjugated bulky poly(p-phenylenevinylene)s and their copolymers</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Polymer Science Part A-Polymer Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">conjugated polymers</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">poly(p-phenylenevinylene)</style></keyword><keyword><style  face="normal" font="default" size="100%">solution properties</style></keyword><keyword><style  face="normal" font="default" size="100%">Structure-property relationship</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">MAY</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">10</style></number><publisher><style face="normal" font="default" size="100%">JOHN WILEY &amp; SONS INC</style></publisher><pub-location><style face="normal" font="default" size="100%">111 RIVER ST, HOBOKEN, NJ 07030 USA</style></pub-location><volume><style face="normal" font="default" size="100%">47</style></volume><pages><style face="normal" font="default" size="100%">2631-2646</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;A new series of symmetrically substituted bulky PPV-copolymers based on poly(bis-2,5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (BEH-PPV) bearing tricyclodecane (TCD) pendants were synthesized to study the effect of chain aggregation in the pi-conjugated polymer backbone. The composition of the copolymers was varied up to 100 mol % and the structures of the copolymer were confirmed by NMR and FTIR. The molecular weights of the copolymers were obtained as M(w) = 11,500-1,78,800 depending on the TCD-incorporation in BEH-PPV. The origin of the pi-aggregation was investigated using mixture of solvents (polar or nonpolar) or temperature as external stimuli. Absorption, photoluminescence, and time-resolved fluorescence decay techniques were employed as tools to trace molecular aggregation in solution and solid state. The TCD-substituted bulky copolymers showed almost twice the enhancement in photoluminescence compared with that of BEH-PPV Solvent-induced aggregation studies of copolymers revealed the existence of strong molecular aggregation in BEH-PPV compared with that of bulky copolymers. Variable temperature studies further evidence for the reversibility of molecular aggregation on beating/cooling cycles and showed isosbetic points with respect to free and aggregated polymer chains. Time-resolved fluorescent studies confirmed the existence of free and aggregated pi-conjugated species with a life time of 0.1 to 1.0 ns. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2631-2646, 2009&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">10</style></issue><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">3.894</style></custom4></record></records></xml>