15 Fakultätsübergreifend / Sonstige Einrichtung

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/16

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1991 - 19922

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Publication Type: search.filters.UBSTyp.KonferenzbeitragAuthor: search.filters.author.Seifert, Udo

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    Vesicle shapes and shape transformations: a systematic study
    (1991) Berndl, Karin; Käs, Josef; Lipowsky, Reinhard; Sackmann, Erich; Seifert, Udo
    In our contribution we report a systematic experimental and theoretical study on shape transformations. In order to avoid the above mentioned complications we have investigated vesicles which consist of electrically neutral lipids (that is phosphatidylcholine) in Millipore water. We find, that even for such a simple system a change in temperature can lead to three different types of shape transformations. Theoretically, we discuss shape transformations within two well established curvature models, (i) the bilayer coupling model of Svetina and Zeks and (ii) the spontaneous curvature model of Helfrichs.A comparison leads to the conclusion that the observed shape transformations can well be explained within the bilayer coupling model provided a small asymmetry in the thermal expansivities of both monolayers is assumed. In some cases, such an asymmetry is not required.
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    Budding transition for bilayer fluid vesicles with area-difference elasticity
    (1992) Seifert, Udo; Miao, Ling; Döbereiner, Hans-Günther; Wortis, Michael
    We consider a curvature model for bilayer vesicles with an area-difference elasticity or non-local bending-energy term. Such a model interpolates between the bilayer-couple and spontaneous-curvature models. We report preliminary results for the budding transition. The shape transformation between the dumbbell and the pear phases can be continuous or discontinuous depending on the ratio of the non-local to the local bending rigidities.