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Self-assembled nanostructured biohybrid coatings by an integrated ‘sol–gel/intercalation’ approach

Fuentes Alventosa, José Maria and Introzzi, Laura and Santo, Nadia and Cerri, Guido and Brundu, Antonio and Farris, Stefano (2013) Self-assembled nanostructured biohybrid coatings by an integrated ‘sol–gel/intercalation’ approach. RSC advances, Vol. 3 (47), p. 25086-25096. eISSN 2046-2069. Article.

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DOI: 10.1039/C3RA45640D

Abstract

The combination of sol–gel technology and intercalation was investigated in this study as a strategy to develop bionanocomposite hybrid materials in the form of coatings with specifically intended oxygen barrier properties. To this goal, the exopolysaccharide pullulan was used as the organic phase, whereas tetraethyl orthosilicate (TEOS) and Na+–montmorillonite (MMT) were used as the metal alkoxide precursor and the nanobuilding blocks (NBB) for the sol–gel technology and the intercalation process, respectively. Complementary information from XRD and TEM analyses disclosed a new supramolecular organization arising from the self-assembly of NBB and pullulan, with the latter apparently intercalated between the clay platelets. Although affected by a rise in haze, the hybrid coatings exhibited outstanding oxygen barrier properties, with permeability coefficient values (P′O2) ranging from 0.89 mL μm m−2 (24 h)−1 atm−1 for a filler volume fraction (ϕ) = 0.017 to an impressive 0.15 mL μm m−2 (24 h)−1 atm−1 (ϕ = 0.095) under dry conditions. Modeling of P′O2 suggested a very tight structure under dry conditions, which yielded an apparent clays aspect ratio (α) 50, whereas in the hydrated state a more realistic α 100 was restored. This finding was further supported by SEM analysis, which also highlighted partial embrittlement of the final hybrid coatings.

Item Type:Article
ID Code:10734
Status:Published
Refereed:Yes
Uncontrolled Keywords:Sol–gel technology, exopolysaccharide pullulan, tetraethyl orthosilicate (TEOS) and Na+–montmorillonite (MMT),
Subjects:Area 04 - Scienze della terra > GEO/09 Georisorse minerarie e applicazioni mineralogico- petrografiche per l'ambiente ed i beni culturali
Divisions:001 Università di Sassari > 01-a Nuovi Dipartimenti dal 2012 > Scienze della Natura e del Territorio
Publisher:RSC Publishing
eISSN:2046-2069
Deposited On:02 Feb 2015 12:40

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