Solid Particle Self-assembly in Time-Periodic Flows:

new Concepts to Manipulate Matter on Small Scales

Marcello Lappa, Paolo Capobianchi and Balagopal Manayil Santhosh

Department of Mechanical and Aerospace Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow, G1 1XJ, UK

^*corresponding author email: marcello.lappa@strath.ac.uk

Application-driven technological demands require vastly superior control of particles and other inclusions dispersed in many inorganic and organic materials when they are in the liquid state. We present a survey of recently discovered mechanisms for solid particle self-assembly, ordering and accumulation in non-isothermal laminar time-periodic fluid flows, potentially inherent to exerting such a control. Assuming surface-tension gradients and vibrational effects as the main mechanisms driving fluid flow, an attempt is made to disentangle the complex hierarchy of relationships existing between the multiplicity of the loci of particle aggregation, the geometry of the physical domain hosting the considered fluid-particle mixture, the physical properties of the particles per se and the applied thermal boundary conditions. We show that the particle self-organization processes in time-periodic thermal flows obey a complex logic, which makes the arrangement of particles different from realization to realization. As some influential conditions or parameters are varied, particles can be gradually transferred from the region of influence of an attractor to another. Moreover, ranges exist where these “attractee” compete resulting in overlapping or intertwined particle structures. The final objective is the integration of new physics in already existing theories and forge a new unified concept for the (contactless) manipulation of solid matter dispersed in a fluid, which may lead in the future to alloys with improved properties or perhaps completely new materials.