Self-assembly processes of superparamagnetic colloids in a quasi-two-dimensional system

Abstract

Superparamagnetic colloids gather depending on the magnitude of the magnetic field applied, forming chains and ribbons in a quasi-two-dimensional chamber. The results presented in this work are in good agreement with recent experimental multistable data for the mean length of the aggregates in thermodynamic equilibrium.

Transitional bulk-solutal Marangoni instability in sessile drops

“…The self-assembly of colloids is currently a topic of intensive research, both on fundamental [1][2][3][4][5][6][7][8][9][10][11] and applied aspects. [12][13][14][15][16][17][18][19][20][21][22] Amongst the self-assembly processes, the evaporation of colloidal droplets has attracted much interest due to its wide range of potential applications, extending from blood analysis [23][24][25][26] via inkjet printing, paint and polymers, [27][28][29] up to and including nanotechnology.…”

Effect of volume fraction on chains of superparamagnetic colloids at equilibrium

“…It can also be used to test some models in range of parameters which are not accessible experimentally. In the case of the analytical models for the mean chains length at saturation, [26,37] such simulations can (dis)confirm the mathematical approximations and the dependencies in the various parameters. However, classical techniques of numerical simulations (Langevin Dynamics, soft sphere discrete element methods, molecular dynamics, ...) would require several years of computing time to reach equilibrium state under some conditions: actual experiments last for hours and one second of simulation currently takes from 300 to 1100 hours of computering time.…”

“…The detailed formation process and the origin of those properties is still an open question. To our knowledge, the only system for which some model of growth has been published in the literature up to now is the colloidal chains formed under constant magnetic fields [12,23,[33][34][35][36][37][38][39]. The assembling mechanisms rely on the characteristic high magnetic response and quasi-zero residual magnetization of the building particles consisting of mag-Send offprint requests to: Alexis Darras a Corresponding author: alexis.darras@uliege.be netic nanoparticles inserted in a matrix of non-magnetic material (polystyrene or silica) [17,18,23,35].…”

Introductory Chapter: An Example in Superparamagnetic Colloids

“…The study of formed (after aggregation) compact regular and quasi-rectangular bundles of number of particles n, width d and length s (these distances are measured in number of grains) has been performed in [5]. In addition to these cases here, a description of non-rectangular (irregular) bundles is included.…”