title: Magnetically enhanced bicelles delivering switchable anisotropy in optical gels.
abstract: Mesostructures responding to external triggers such as temperature, pH, or magnetic field have the potential to be used as self-acting sensors, detectors, or switches. Key features are a strong and well-defined response to the external trigger. Here, we present magnetic alignable bicelles embedded into a gelatin matrix generating magnetically switchable structures, which can reversibly be locked and unlocked by adjusting the temperature. We show that the disk-like aggregates can be orientated in magnetic fields, and such orientation can be preserved after embedding into gelatin. The resulting gel cubes show an anisotropic transfer for electromagnetic waves, i.e., a different spatial birefringence. Cycling through the melting point of gelatin sets the structure back to its isotropic state providing a read-out of the thermal history. Stacking of the bicelles induced by the gelatin promotes magnetic aligning, as an increased aggregation number in the stacks increases the magnetic orientation energy.
authors.affiliation: Laboratory of Food Process Engineering, ETH Zurich , Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
authors.forename: Marianne
authors.initials: M
authors.lastname: Liebi
authors.forename: Simon
authors.initials: S
authors.lastname: Kuster
authors.forename: Joachim
authors.initials: J
authors.lastname: Kohlbrecher
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Peter
authors.initials: P
authors.lastname: Fischer
authors.forename: Peter
authors.initials: P
authors.lastname: Walde
authors.forename: Erich J
authors.initials: EJ
authors.lastname: Windhab