Dynamic Self‐Assembly of Magnetic/Polymer Composites in Rotating Frames of Reference

Abstract

Small ferromagnetic particles suspended in a rotating viscous polymer and subjected to an external static magnetic field dynamically self-assemble into open-lattice, periodic structures. Depending on the orientation of the magnetic field with respect to the system's axis of rotation, these structures range from arrays of parallel plates to single, double, triple, or even quaternary helices. Dynamic self-assembly in this rotating frame of reference can be explained by an interplay between magnetic, dipole-dipole, viscous drag, and centripetal forces. Once formed, the dynamic aggregates can be made permanent by thermally curing the polymer matrix.

Non‐Equilibrium Self‐Assembly of Monocomponent and Multicomponent Tubular Structures in Rotating Fluids

“…While the packing of equally sized particles has been studied theoretically and understood in detail, [3,[14][15][16][17] it has proven difficult to a priori predict/control assembly of specific structures in experiment. Here, we describe non-equilibrium selfassembly [18,19] of ordered tubular structures which relies not only on molecular-or colloidal-scale particle-particle interactions [6][7][8][9][10][11][12][13] but also on fluidic confinement imposed by a rotating fluid [20] denser than the assembling particles. Here, we describe non-equilibrium selfassembly [18,19] of ordered tubular structures which relies not only on molecular-or colloidal-scale particle-particle interactions [6][7][8][9][10][11][12][13] but also on fluidic confinement imposed by a rotating fluid [20] denser than the assembling particles.…”

“…In addition, there have been no works that would consider tubular packing in mixtures of particles of different sizes. Here, we describe non-equilibrium selfassembly [18,19] of ordered tubular structures which relies not only on molecular-or colloidal-scale particle-particle interactions [6][7][8][9][10][11][12][13] but also on fluidic confinement imposed by a rotating fluid [20] denser than the assembling particles. By adjusting the sizes and numbers of these particles, it is then possible to the rotating tube cool down to room temperature.…”

“…10 mm; O.D. Here, we describe non-equilibrium selfassembly [18,19] of ordered tubular structures which relies not only on molecular-or colloidal-scale particle-particle interactions [6][7][8][9][10][11][12][13] but also on fluidic confinement imposed by a rotating fluid [20] denser than the assembling particles. The tube is sealed (so that no air bubbles remain inside) and mounted onto a commercial lathe (Sherline Products 4100A-DRO) for which the angular velocities can be adjusted up to ω = 10 000 rpm.…”

Helical Magnetic Field-Induced Real-Time Plasmonic Chirality Modulation

“…Changing the concentration from 50 to 200 mg mL –1 did not shift the peak wavelength significantly (from 780 to 770 nm) but affected peak intensity (Figure S13). The concentration change mainly affects chain length as the magnetic flux density is not changed . The increased chain length increases the number of skew line configurations that are correlated with an increased peak intensity.…”

“…The concentration change mainly affects chain length as the magnetic flux density is not changed. 41 The increased chain length increases the number of skew line configurations that are correlated with an increased peak intensity. Since the helical nanochain structures assembled under the hB resemble chiral nematics in liquid crystals, which can rotate the polarized direction of linearly polarized light, our metaliquid crystals realize full-color tuning capabilities by simple rotation of the polarizer without the need of a color filter (Figure 6a).…”