Dresden 2017 – scientific programme

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BP: Fachverband Biologische Physik

BP 22: Posters - Biomaterials and Biopolymers

BP 22.7: Poster

Tuesday, March 21, 2017, 14:00–16:00, P1A

Liquid crystalline ordering of amyloid-iron(II,III) oxide hybrid fibrils under magnetic field — •Jianguo Zhao¹, Sreenath Bolisetty¹, Stephane Isabettini², Joachim Kohlbrecher³, Jozef Adamcik¹, Peter Fishcer², and Raffaele Mezzenga¹ — ¹Laboratory of Food and Soft Materials, D-HEST, ETH Zurich — ²Laboratory of Food Process Engineering, D-HEST, ETH Zurich — ³Laboratory of Neutron Scattering and Imaging, PSI

Magnetic field is a promising approach to induce spatial ordering in the originally disordered suspension of magneto-responsive rod-like particles. By loading iron(II,III) oxide nanoparticles with amyloid fibrils, we fabricated hybrid fibrils having high magneto-responsiveness, high aspect ratio (length-to-diameter, L/D) and flexibility. An apparently increased orientation was obtained upon increasing magnetic field strength and fibrils volume fraction (phi). At constant dimensionless concentration (phi*L/D), stiff hybrid fibrils with varied aspect ratios and volume fractions displayed identical degree of ordering at constant magnetic field; while the semiflexible fibrils with contour length close to persistence length exhibited a lower degree of alignment. To the best of our knowledge, this is first direct experimental proof of Khokhlov-Semenov theory, which predicts that the ordered phase for anisotropic colloidal particles is highly restricted by the semiflexible nature of the particles under external fields. We believe these findings are detrimental for the fundamental understanding and applications of liquid crystalline phases in numerous external fields. *current address: Drittes Physikalisches Institut, Georg-August-Universität Göttingen.