Dilational Rheology of Mixed Lipid-Nanoparticle Layer at Water/Air Interface (Abstract/Comunicazione in atti di convegno)

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Label
  • Dilational Rheology of Mixed Lipid-Nanoparticle Layer at Water/Air Interface (Abstract/Comunicazione in atti di convegno) (literal)
Anno
  • 2012-01-01T00:00:00+01:00 (literal)
Alternative label
  • Francesca Ravera, Eduardo Guzmán, Michele Ferrari, Eva Santini, Libero Liggieri (2012)
    Dilational Rheology of Mixed Lipid-Nanoparticle Layer at Water/Air Interface
    in 10th EUFOAM 2012, Lisboa, Portugal
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Francesca Ravera, Eduardo Guzmán, Michele Ferrari, Eva Santini, Libero Liggieri (literal)
Note
  • Comunicazione (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • CNR - Istituto per l'Energetica e le Interfasi, Genoa, Italy (literal)
Titolo
  • Dilational Rheology of Mixed Lipid-Nanoparticle Layer at Water/Air Interface (literal)
Abstract
  • The association of surfactants with solid particles of nanometric dimensions at the liquid interfaces of bubbles and drops has been recently widely investigated because of the importance of this kind of systems in several natural phenomena and technologies related to the production and stabilization of emulsions and foams. It is now well known that investigating the dilational rheology of interfacial layers is an effective way to study the stability of liquid films and foams because it provides a good description of the mechanical properties of these systems and, especially if composite systems are involved undergoing complex reorganization processes, it allows a quantitative comprehension of their mechanisms. In this study we investigated the dilational rheological properties of monolayer of fatty anphililes, essentially composed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and/or Palmitic acid, in presence of solid nanoparticles (NP) of different chemical nature (silica, carbon, titania) and degree of hydrophobicity. These mixed lipid-NP layers are spread on aqueous sub-phase and investigated by using two complementary techniques: oscillatory barrier method in a Langmuir balance and oscillating drop in a drop shape tensiometer. The coupling of these two techniques allows obtaining information on the mechanical behaviour of these interfacial layers and on how it is modified by the presence of the different nanoparticles, measuring the dilational viscoelasticity in a frequency range from 10-3 to around 1 Hz. In particular, it was pointed out that the viscoelastic features of the investigated lipid monolayers strongly dependent on their phase behaviour and, for this reason are modified by the NP incorporation. The general effect of NP is a decrease of the quasi equilibrium dilational elasticity while, as the high frequency limit elasticities are maintained rather unchanged, important modifications are observed in the values at intermediate frequency, strongly dependent on the NP chemical characteristics and concentration. The combination of the results here obtained with those of previous studies on the thermodynamic and structural properties of this kind of mixed layers, allows concluding that the dilational rheology characteristics of these systems make them interesting for the their application in the filed of particle stabilized foams. References E. Guzmán, et al, J. Phys. Chem. C 115, 21715 (2011). E. Guzmán et al., Colloids and Surfaces A doi:10.1016/j.colsurfa.2011.12.059 (2012) . E. Guzmán et al, Soft Matter 8, 3938 (2012). (literal)
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