title: Concentration effects on the dynamics of liquid crystalline self-assembly: time-resolved X-ray scattering studies.
abstract: A manifold of ordering transitions relevant to chemical and biological systems occur at interfaces from liquids to self-assembled soft solids like membranes or liquid crystals. In the present case, we were interested in understanding the phase transition from the microemulsion phase to the liquid crystal phase in terms of their driving forces, i.e., activation energy and entropy. The purpose of this work was to clarify the influence of concentration effects of the amphiphilic molecules on the nature of these self-assembly processes. By photosensitization of the model system (polyalkylglycolether (C(10)E(4)), water, decane, and cyclohexane) with laser dyes, we could effectively induce and control the phase transition through the absorption of optical photons. The photo transformation conditions were chosen in such a way that the system was in thermal equilibrium. By application of time-resolved photo small-angle X-ray scattering we could monitor the conversion process and demonstrate that the surfactant concentration has a direct impact on the activation energy, which is observable through the length of the induction time.
authors.affiliation: Department of Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Petri
authors.forename: Andreas
authors.initials: A
authors.lastname: Menzel
authors.forename: Oliver
authors.initials: O
authors.lastname: Bunk
authors.forename: Gerhard
authors.initials: G
authors.lastname: Busse
authors.forename: Simone
authors.initials: S
authors.lastname: Techert
mesh_terms: D050866:Liquid Crystals / Q000737:chemistry*; D008722:Methods; D056004:Molecular Dynamics Simulation; D044367:Phase Transition; D017319:Photosensitizing Agents; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D017319:Photosensitizing Agents