2013/09/06 by Alexander Tokarev, Tokarev, Alexander, Wah-Keat Lee +7
Biochemistry, Genetics and Molecular Biology · Materials Science · #FOS: Physical sciences #Liquid Crystal Research Advancements #Materials Science (cond-mat.mtrl-sci) #Pickering emulsions and particle stabilization #Plant Reproductive Biology
paper · pdf · doi:10.48550/arxiv.1309.1513
openalex publication_date 2013/09/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In a non-uniform magnetic field, the droplets of colloids of nickel nanorods and nanoparticles aggregate to form a cusp at the droplet surface not deforming the entire droplet shape. When the field is removed, nanorods diffuse away and cusp disappears. Spherical particles can form cusps in a similar way, but they stay aggregated after release of the field; finally, the aggregates settle down to the bottom of the drop. X-ray phase contrast imaging reveals that nanorods in the cusps stay parallel to each other without visible spatial order of their centers of mass. Formation of cusps can be explained with a model that includes magnetostatic and surface tension forces. The discovered possibility of controlled assembly and quenching of nanorod orientation under the cusped liquid surface offers vast opportunities for alignment of carbon nanotubes, nanowires and nanoscrolls, prior to spinning them into superstrong and multifunctional fibers. Magneto and electrostatic analogy suggests that similar ideal alignment can be achieved with the rod-like dipoles subject to a strong electric filed.