SWOLLEN MICELLES PLUS HYDROPHOBICALLY MODIFIED HYDROSOLUBLE POLYMERS IN AQUEOUS SOLUTIONS: DECORATION VERSUS BRIDGING. A SMALL ANGLE NEUTRON SCATTERING STUDY. Auteur(s): Filali Mohammed, Aznar R., Svenson Mattias, Porte Grégoire, Appell Jacqueline (Article) Publié: The Journal Of Physical Chemistry B, vol. 103 p.7293-7301 (1999) Texte intégral en Openaccess : Ref HAL: hal-00003063_v1 Ref Arxiv: cond-mat/0410292 DOI: 10.1021/jp990980d WoS: 000082335700032 Ref. & Cit.: NASA ADS Exporter : BibTex | endNote 54 Citations Résumé: In this paper we examine the effective interactions introduced between the droplets of an oil in water microemulsion upon progressive addition of hydrophobically modified water soluble poly(ethylene oxide)-PEO using essentially small angle neutron scattering. To discuss the relative importance of decoration and bridging of the droplets we compare analogous samples with addition of a PEO grafted at both extremities with hydrophobic C12H 25 chains (PEO-2m) or addition of a PEO grafted at one extremity only with a C12H 25 chain (PEO-m). PEO-m or PEO-2m adsorb onto the droplets via their hydrophobic extremities and the droplets are found to retain their form and size upon addition of up to 40 hydrophobic C12H 25 chains per droplet. When the volume fraction of droplets is less than about 10%, the effective interactions introduced by PEO-m or PEO-2m are found to be very different: PEO-m introduces a repulsive interaction while PEO-2m introduces an effective attractive interaction. This attractive interaction leads to an associative phase separation in the range of low volume fraction when a sufficient amount of PEO-2m is added. |