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Phase Coexistence in a Dynamic Phase Diagram
Author(s) -
Gentile Luigi,
Coppola Luigi,
Balog Sandor,
Mortensen Kell,
Ranieri Giuseppe A.,
Olsson Ulf
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500237
Subject(s) - phase diagram , lamellar phase , lamellar structure , shear flow , colloid , phase (matter) , metastability , neutron scattering , chemical physics , dynamic light scattering , vesicle , phase transition , spectroscopy , chemistry , materials science , rheology , crystallography , scattering , thermodynamics , nanotechnology , optics , nanoparticle , organic chemistry , physics , membrane , biochemistry , composite material , quantum mechanics
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 (L 3 ) and MLV‐to‐L α transitions upon increasing temperature are detected using flow small‐angle neutron scattering techniques. Coexistence of L α 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.