%0 Journal Article %1 Gotter2007 %A Gotter, M. %A Sottmann, T. %A Baciu, M. %A Olsson, U. %A Wennerström, H. %A Strey, R. %D 2007 %J The European Physical Journal E %K Sottmann from:mkrappel %N 3 %P 277 %R 10.1140/epje/i2007-10238-8 %T A comprehensive, time-resolved SANS investigation of temperature-change-induced sponge-to-lamellar and lamellar-to-sponge phase transformations in comparison with 2H -NMR results %U https://doi.org/10.1140/epje/i2007-10238-8 %V 24 %X Time-resolved small-angle neutron scattering (TR-SANS) was employed to observe temperature-induced phase transitions from the sponge (L 3 to the lamellar ( L α phase, and vice versa, in the water-oil (n -decane)-non-ionic surfactant ( C12E5 system using both bulk and film contrast. Samples of different bilayer volume fractions φ and solvent viscosities η were investigated applying various amplitudes of temperature jump ΔT . The findings of a previous 2H -NMR study could be confirmed, where the lamellar phase formation was determined to occur through a nucleation and growth process, while it was concluded that the L 3 -phase develops in a mechanistically different and more rapid manner involving uncorrelated passage formation. Likewise, the kinetic trends of the nucleation and growth transition (decreased transition time with increase of φ and ΔT were witnessed once again. Additionally, NMR and SANS data that demonstrate a strong dependency of that process on solvent viscosity η are presented. Contrariwise, it is made evident via both SANS and NMR results that the L α -to-L 3 transition time is independent (within experimental sensitivity) of the varied parameters (φ , ΔT , η . Unusual scattering evolution in one experiment, originating from a highly ordered lamellar phase, intriguingly hints that a major rate determining factor is the disruption of long-range order. Furthermore, the bulk contrast investigations give insight into structure peak shifts/development during the transitions, while the film contrast experiments prove the bilayer thickness to be constant throughout the phase transitions and show that there is no evidence for a change in the short-range order of the bilayer structure. The latter was considered possible, due to the different topology of the L 3 and L α phases. Lastly, an unexpected yet consistent appearance of anisotropic scattering is detected in the L 3 -to- L α transitions.

@article{Gotter2007, abstract = {Time-resolved small-angle neutron scattering (TR-SANS) was employed to observe temperature-induced phase transitions from the sponge (L 3 to the lamellar ( L α phase, and vice versa, in the water-oil (n -decane)-non-ionic surfactant ( C12E5 system using both bulk and film contrast. Samples of different bilayer volume fractions φ and solvent viscosities η were investigated applying various amplitudes of temperature jump ΔT . The findings of a previous 2H -NMR study could be confirmed, where the lamellar phase formation was determined to occur through a nucleation and growth process, while it was concluded that the L 3 -phase develops in a mechanistically different and more rapid manner involving uncorrelated passage formation. Likewise, the kinetic trends of the nucleation and growth transition (decreased transition time with increase of φ and ΔT were witnessed once again. Additionally, NMR and SANS data that demonstrate a strong dependency of that process on solvent viscosity η are presented. Contrariwise, it is made evident via both SANS and NMR results that the L α -to-L 3 transition time is independent (within experimental sensitivity) of the varied parameters (φ , ΔT , η . Unusual scattering evolution in one experiment, originating from a highly ordered lamellar phase, intriguingly hints that a major rate determining factor is the disruption of long-range order. Furthermore, the bulk contrast investigations give insight into structure peak shifts/development during the transitions, while the film contrast experiments prove the bilayer thickness to be constant throughout the phase transitions and show that there is no evidence for a change in the short-range order of the bilayer structure. The latter was considered possible, due to the different topology of the L 3 and L α phases. Lastly, an unexpected yet consistent appearance of anisotropic scattering is detected in the L 3 -to- L α transitions.}, added-at = {2020-08-03T08:28:45.000+0200}, author = {Gotter, M. and Sottmann, T. and Baciu, M. and Olsson, U. and Wennerstr{\"o}m, H. and Strey, R.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2b4bf4390d37cf5c037f7b4407e6d84eb/ak_sottmann}, day = 17, doi = {10.1140/epje/i2007-10238-8}, interhash = {a7a8a529fe8cdade253810d0bbd022b3}, intrahash = {b4bf4390d37cf5c037f7b4407e6d84eb}, issn = {1292-895X}, journal = {The European Physical Journal E}, keywords = {Sottmann from:mkrappel}, month = dec, number = 3, pages = 277, timestamp = {2020-08-03T06:28:45.000+0200}, title = {A comprehensive, time-resolved SANS investigation of temperature-change-induced sponge-to-lamellar and lamellar-to-sponge phase transformations in comparison with 2H -NMR results}, url = {https://doi.org/10.1140/epje/i2007-10238-8}, volume = 24, year = 2007 }