resumo
A series of polysaccharide-based transparent composite films containing lanthanopolyoxometalates (LnPOMs) have been prepared by using a water-soluble cationic chitosan derivative [HTCC = N-(2-hydroxypropyl)-3-trimethylammonium chitosan chloride] and pullulan (PUL). HTCC was more suitable than pure chitosan for this purpose due to its positive charge and solubility in water over a broad range of pH values. The LnPOMs [Ln(W5O18)2]9 (Ln = Eu and Tb) were incorporated into the polysaccharides. EuPOMs encapsulated in amorphous silica shells were also incorporated into the polysaccharides to test the effect on film processing of the loading of nanoparticles instead of LnPOM anions. The incorporation of LnPOMs or LnPOM/silica core/shell nanoparticles into either HTCC or PUL polysaccharides originated clear transparent films. These composite films are transparent in daylight and exhibit visible emission under UV excitation. Photoluminescence studies (emission and excitation spectra and emission decay curves) were performed on the newly prepared films.
palavras-chave
3-HYDROXYPICOLINIC ACID; HYBRID MATERIALS; POLYOXOMETALATE; CHITOSAN; COMPLEXES; CHEMISTRY; POLYOXOTUNGSTOEUROPATE; ELECTROCHROMISM; FABRICATION; ANION
categoria
Chemistry
autores
Pinto, RJB; Granadeiro, CM; Freire, CSR; Silvestre, AJD; Neto, CP; Ferreira, RAS; Carlos, LD; Cavaleiro, AMV; Trindade, T; Nogueira, HIS
nossos autores
Ana Maria Vieira Silva Viana Cavaleiro
Professor Catedrático
Armando Jorge Domingues Silvestre
Professor Catedrático
Carlos Miguel Cardeal Enes Granadeiro
Bolseiro de pós-Doutoramento
Carlos Pascoal Neto
Diretor do Raiz
Carmen Sofia da Rocha Freire Barros
Investigador Principal
Helena Isabel Seguro Nogueira
Professor Auxiliar
Luís António Ferreira Martins Dias Carlos
Professor Catedrático
Maria Rute de Amorim e Sá Ferreira André
Vice-Diretor
Ricardo Pinto
Investigador
Tito Trindade
Professor CatedráticoGrupos
1 - Nanomateriais inorgânicos funcionais e híbridos orgânico-inorgânico
4 - biorrefinarias, materiais de origem biológica e reciclagem
agradecimentos
The authors thank the Centro de Investigacao em Materiais Ceramicos e Compositos (CICECO) and the Fundacao para a Ciencia e a Tecnologia (FCT) for funding. R. J. B. P. and C. M. G. thank the FCT for a Ph. D. grant (SFRH/BD//45364/2008) and post-doctoral grant (SFRH/BPD/73191/2010), respectively.