resumo
New composites of nanofibrillated cellulose (NFC) and ZnO nanoparticles (NP) have been prepared by electrostatic assembly in aqueous medium and using polyelectrolytes as macromolecular linkers. Selected NFC/ZnO systems were employed as fillers in starch based coating formulations for Eucalyptus globulus-based paper sheets. Using this method, antibacterial paper with low content of ZnO (<0.03%) and slight improvements in air permeability and mechanical properties were obtained. The antibacterial activity of the ZnO/NFC coatings was investigated namely by submitting paper samples to solar light exposure and dark conditions. In both conditions, the paper samples have shown bacteriostatic and/or bactericidal activity against Gram positive (Staphylococcus aureus and Bacillus cereus) and Gram negative (Klebsiella pneumoniae) bacteria. These results seem to support that the mechanism for ZnO antimicrobial activity is not mediated only by the photoactivity of the semiconductor but also by oxidizing species formed at the particles surfaces. (C) 2012 Elsevier B.V. All rights reserved.
palavras-chave
OXIDE NANOPARTICLES; SILVER; FUNCTIONALIZATION; SUSPENSIONS; INHIBITION; GENERATION; BACTERIAL; SURFACES; FIBERS; GROWTH
categoria
Chemistry
autores
Martins, NCT; Freire, CSR; Neto, CP; Silvestre, AJD; Causio, J; Baldi, G; Sadocco, P; Trindade, T
nossos autores
Armando Jorge Domingues Silvestre
Professor Catedrático
Carlos Pascoal Neto
Diretor do Raiz
Carmen Sofia da Rocha Freire Barros
Investigador Coordenador
Natércia da Conceição Tomé Martins
Investigador Júnior
Tito Trindade
Professor Catedráticoagradecimentos
The research leading to these results has received funding from the European Community's Seventh Framework Programme under grant agreement no 228802 (SunPap project) and from CICECO (Pest-C/CTM/LA0011/2011). The authors thank the VTT, Technical Research Centre of Finland and Centre Technique du Papier (CTP, France) for supplying the NFC used in this work. We also thank RAIZ- Centro de Investigacao da Floresta e do Papel (Portugal) for all the facilities provided in the paper coating experiments.