2016/04/25 by Johnny Nguyen, Nguyen, Johnny, Sonia Contera +4
Biochemistry, Genetics and Molecular Biology · Chemistry · Engineering · Physics and Astronomy · #Biological Physics (physics.bio-ph) #Electrostatics and Colloid Interactions #FOS: Physical sciences #Magnetic and Electromagnetic Effects #Microfluidic and Bio-sensing Technologies #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft #physics.bio-ph
paper · pdf · doi:10.48550/arxiv.1604.07239
11 pages, 11 figures. See videos online at RSC Advances
arxiv created 2016/04/25 · openalex publication_date 2016/04/25 · arxiv updated 2016/04/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We demonstrate, for the first time, confinement of the orientation of micron-sized graphitic flakes to a well-defined plane. We orient and rotationally trap lipid-coated highly ordered pyrolytic graphite (HOPG) micro-flakes in aqueous solution using a combination of uniform magnetic and AC electric fields and exploiting the anisotropic diamagnetic and electrical properties of HOPG. Measuring the rotational Brownian fluctuations of individual oriented particles in rotational traps, we quantitatively determine the rotational trap stiffness, maximum applied torque and polarization anisotropy of the micro-flakes, as well as their dependency on the electric field frequency. Additionally, we quantify interactions of the micro-particles with adjacent glass surfaces with various surface treatments. We outline the various applications of this work, including torque sensing in biological systems.