title: Nature of Mesoscopic Organization in Protic Ionic Liquid-Alcohol Mixtures.
abstract: The mesoscopic morphology of mixtures of ethylammonium nitrate, a protic ionic liquid, and n-pentanol is explored for the first time using small angle X-ray scattering as a function of concentration and temperature. Both compounds are amphiphilic and characterized by an extended hydrogen bonding network; however, though macroscopically homogeneous, their mixtures are highly heterogeneous at the mesoscopic spatial scales. Previous structural studies rationalized similar features in related mixtures proposing the existence of large aggregates or micelle- and/or microemulsion-like structures. Here we show that a detailed analysis of the present concentration and temperature resolved experimental data set supports a structural scenario where the mesoscopic heterogeneities are the due to density fluctuations that are precursors of liquid-liquid phase separation. Accordingly no existence of structurally organized aggregates (such as micellar or microemulsion aggregates) is required to account for the mesoscopic heterogeneities detected in this class of binary mixtures.
authors.affiliation: Fachbereich 2 Biologie-Chemie, Universität Bremen , Bremen, Germany.
authors.forename: Wolffram
authors.initials: W
authors.lastname: Schroer
authors.affiliation: Laboratorio Liquidi Ionici, Istituto Struttura della Materia, Consiglio Nazionale delle Ricerche , Rome, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Triolo
authors.affiliation: Dipartimento di Chimica, Università di Roma Sapienza , Rome, Italy.
authors.forename: Olga
authors.initials: O
authors.lastname: Russina