Side-chain motions in poly(methyl methacrylate) plus SiO2 hosts of fluorescent dyes studied by thermally stimulated discharge currents: effects of confinement and blending

Kalogeras, IM

dc.contributor.author	Kalogeras, IM	en
dc.date.accessioned	2014-03-01T01:53:12Z
dc.date.available	2014-03-01T01:53:12Z
dc.date.issued	2003	en
dc.identifier.issn	0032-3861	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/26886
dc.subject	polymethyl methacrylate	en
dc.subject	dyes	en
dc.subject	nanocomposites	en
dc.subject.classification	Polymer Science	en
dc.subject.other	SILICA GLASS COMPOSITES	en
dc.subject.other	ORGANIC LASER-DYES	en
dc.subject.other	POROUS GEL SILICA	en
dc.subject.other	T-G RELAXATIONS	en
dc.subject.other	RHODAMINE 6G	en
dc.subject.other	SOL-GEL	en
dc.subject.other	DIELECTRIC CHARACTERIZATION	en
dc.subject.other	CHROMOPHORE REORIENTATION	en
dc.subject.other	POLYMERIC MATRICES	en
dc.subject.other	OPTICAL-PROPERTIES	en
dc.title	Side-chain motions in poly(methyl methacrylate) plus SiO2 hosts of fluorescent dyes studied by thermally stimulated discharge currents: effects of confinement and blending	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	2003	en
heal.abstract	The thermally stimulated discharge (TSD) currents technique has been used to study different types of inter- and intra-molecular interactions between the components in poly(methyl methacrylate) (PMMA)-based systems. The TSD current signal of the side-chain dielectric beta relaxation mode of PMMA has been comparatively studied in bulk PMMA, PMMA polymerized in-situ mesoporous silica-gel, and these matrices in the presence of polar and ionic (rhodamine 6G/Cl-) or non-polar (perylene derivatives) fluorescent dyes. The analysis of the TSD responses by means of partial heating and thermal sampling techniques indicates that polymer's confinement in SiO2 induces, firstly, an increase of the distributed energy barriers of the beta relaxation mode, and secondly, an enhancement of the contribution of the faster relaxation modes (at T < T-max(beta)) in the overall strength of the beta mechanism. Basic features of the beta bands (i.e. peak maximum and distribution of activation energies) exclude the occurrence of strong interactions between the perylene derivatives and the carbonyl groups of PMMA. To contrary, coupling effects appear between the motions of the side-groups of PMMA and rhodamine 6G. The results are interpreted in view of counteracting structural (e.g. modification of the polymer's free volume) and surface (hydrogen-bond interphase interactions) effects of confinement and blending on the relaxation dynamics of the pendant groups. (C) 2003 Elsevier Science Ltd. All rights reserved.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	POLYMER	en
dc.identifier.isi	ISI:000184351500008	en
dc.identifier.volume	44	en
dc.identifier.issue	17	en
dc.identifier.spage	4817	en
dc.identifier.epage	4827	en