title: SAXS reveals the magnetic alignment pathway of the goethite columnar liquid crystal phase.
abstract: The alignment of board-like colloidal goethite particles in the dense rectangular centred columnar liquid crystal phase in an external magnetic field is studied using small angle X-ray scattering (SAXS). Transient SAXS-patterns show broadening of the columnar reflections in specific directions. While the reflections along the field stay at a constant Q-value, the other reflections do not. These results imply a certain pathway of reorientation. It appears that alignment proceeds via collective rotation of domains inducing 'nanoshear' between the layers of particles, which slide over each other. The results support the recently suggested martensitic transition pathway for the simple and centred rectangular columnar phases, which were found to spontaneously transform into each other in another goethite system. The results also provide a fine example of how SAXS can be used to study reorientation behaviour of liquid crystals at the nanoscale.
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Department of Chemistry of Utrecht University, Padualaan 8, P.O. Box 80.051, Utrecht 3584CH, The Netherlands. Electronic address: anke.lopr@gmail.com.
authors.forename: Anke B G M
authors.initials: AB
authors.lastname: Leferink op Reinink
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Department of Chemistry of Utrecht University, Padualaan 8, P.O. Box 80.051, Utrecht 3584CH, The Netherlands. Electronic address: e.vandenpol@gmail.com.
authors.forename: Esther
authors.initials: E
authors.lastname: van den Pol
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Department of Chemistry of Utrecht University, Padualaan 8, P.O. Box 80.051, Utrecht 3584CH, The Netherlands. Electronic address: g.j.vroege@uu.nl.
authors.forename: Gert Jan
authors.initials: GJ
authors.lastname: Vroege
authors.affiliation: Van 't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute for Nanomaterials Science, Department of Chemistry of Utrecht University, Padualaan 8, P.O. Box 80.051, Utrecht 3584CH, The Netherlands. Electronic address: a.v.petukhov@uu.nl.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Petukhov
keywords: Goethite board-like colloids; Lyotropic columnar liquid crystal; Magnetic field; Reorientation dynamics; SAXS