title: Phase Coexistence in a Dynamic Phase Diagram.
abstract: Metastability and phase coexistence are important concepts in colloidal science. Typically, the phase diagram of colloidal systems is considered at the equilibrium without the presence of an external field. However, several studies have reported phase transition under mechanical deformation. The reason behind phase coexistence under shear flow is not fully understood. Here, multilamellar vesicle (MLV)-to-sponge (L3 ) and MLV-to-Lα transitions upon increasing temperature are detected using flow small-angle neutron scattering techniques. Coexistence of Lα and MLV phases at 40 °C under shear flow is detected by using flow NMR spectroscopy. The unusual rheological behavior observed by studying the lamellar phase of a non-ionic surfactant is explained using (2) H NMR and diffusion flow NMR spectroscopy with the coexistence of planar lamellar-multilamellar vesicles. Moreover, a dynamic phase diagram over a wide range of temperatures is proposed.
authors.affiliation: Department of Chemistry and Chemical Technology, University of Calabria, P. Bucci 14C, 87036 Rende (Italy). luigi.gentile@unical.it.|Physical Chemistry Division, Chemistry Department, Lund University, P.O. Box 124, 221 00 Lund (Sweden). luigi.gentile@unical.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Gentile
authors.affiliation: Department of Chemistry and Chemical Technology, University of Calabria, P. Bucci 14C, 87036 Rende (Italy).
authors.forename: Luigi
authors.initials: L
authors.lastname: Coppola
authors.affiliation: Laboratory for Neutron Scattering, Paul Scherrer Institut, 5232, Villigen (Switzerland).|Adolphe Merkle Institute, University of Fribourg, 1700 Fribourg (Switzerland).
authors.forename: Sandor
authors.initials: S
authors.lastname: Balog
authors.affiliation: Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark).
authors.forename: Kell
authors.initials: K
authors.lastname: Mortensen
authors.affiliation: Department of Chemistry and Chemical Technology, University of Calabria, P. Bucci 14C, 87036 Rende (Italy).
authors.forename: Giuseppe A
authors.initials: GA
authors.lastname: Ranieri
authors.affiliation: Physical Chemistry Division, Chemistry Department, Lund University, P.O. Box 124, 221 00 Lund (Sweden).
authors.forename: Ulf
authors.initials: U
authors.lastname: Olsson
keywords: dynamic phase diagram; lamellar phase; phase coexistence; shear-induced transitions; vesicles