The thermodynamic properties of monolayers of double chain cationic lipids DOTAP at the air-water interface have been investigated by means of surface pressure and surface potential measurements. We studied the interfacial properties of the film in the liquid-expanded regime during the isothermal compression in the presence of oppositely charged linear polyions (poly (acryl ate) sodium salt, [NaPA]) of different molecular weights. The influence of the ionic character of the aqueous subphase on the polyion adsorption has been studied in different environmental conditions, considering different subphase compositions, ranging from a polyion solution at different concentrations to a salty polyion solution, containing different amount of simple added salt [NaCl]. The data are compared to the ones when only NaCl salt is present in the subphase. The results have been analyzed according to an osmotic-type equation of state and the characteristic parameter associated with the water activity has been evaluated as a function the different molecular weight polyion content. The influence of the simple salt in the adsorption process has been discussed in the light of current scaling theories of polyelectrolyte solutions and the critical salt concentrations inducing a polyion desorption in the different experimental conditions investigated have been estimated. (c) 2007 Elsevier B.V. All rights reserved.
Phenomenological surface characterization of cationic-lipid monolayers in the presence of oppositely charged polyions / Truzzolillo, Domenico; Bordi, Federico; Cametti, Cesare; Sennato, Simona. - In: COLLOIDS AND SURFACES. A, PHYSICOCHEMICAL AND ENGINEERING ASPECTS. - ISSN 0927-7757. - STAMPA. - 319:1-3(2008), pp. 51-61. (Intervento presentato al convegno Joint Conference of the 20th European-Colloid-and-Interface-Society/18th European Chemistry at Interfaces Conference tenutosi a Budapest, HUNGARY nel SEP 17-22, 2006) [10.1016/j.colsurfa.2007.05.007].
Phenomenological surface characterization of cationic-lipid monolayers in the presence of oppositely charged polyions
TRUZZOLILLO, DOMENICO;BORDI, FEDERICO;CAMETTI, Cesare;SENNATO, Simona
2008
Abstract
The thermodynamic properties of monolayers of double chain cationic lipids DOTAP at the air-water interface have been investigated by means of surface pressure and surface potential measurements. We studied the interfacial properties of the film in the liquid-expanded regime during the isothermal compression in the presence of oppositely charged linear polyions (poly (acryl ate) sodium salt, [NaPA]) of different molecular weights. The influence of the ionic character of the aqueous subphase on the polyion adsorption has been studied in different environmental conditions, considering different subphase compositions, ranging from a polyion solution at different concentrations to a salty polyion solution, containing different amount of simple added salt [NaCl]. The data are compared to the ones when only NaCl salt is present in the subphase. The results have been analyzed according to an osmotic-type equation of state and the characteristic parameter associated with the water activity has been evaluated as a function the different molecular weight polyion content. The influence of the simple salt in the adsorption process has been discussed in the light of current scaling theories of polyelectrolyte solutions and the critical salt concentrations inducing a polyion desorption in the different experimental conditions investigated have been estimated. (c) 2007 Elsevier B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
