Light-induced manipulation of passive and active microparticles

The European Physical Journal E, vol. 44, pp. 50

Abstract

We consider sedimented at a solid wall particles that are immersed in water containing small additives of photosensitive ionic surfactants. It is shown that illumination with an appropriate wavelength, a beam intensity profile, shape and size could lead to a variety of dynamic, both unsteady and steady state, configurations of particles. These dynamic, well-controlled and switchable particle patterns at the wall are due to an emerging diffusio-osmotic flow that takes its origin in the adjacent to the wall electrostatic diffuse layer, where the concentration gradients of surfactant are induced by light. The conventional nonporous particles are passive and can move only with already generated flow. However, porous colloids actively participate themselves in the flow generation mechanism at the wall, which also sets their interactions that can be very long ranged. This light-induced diffusio-osmosis opens novel avenues to manipulate colloidal particles and assemble them to various patterns. We show in particular how to create and split optically the confined regions of particles of tunable size and shape, where well-controlled flow-induced forces on the colloids could result in their crystalline packing, formation of dilute lattices of well-separated particles, and other states.

Authors 7

1. Pooja Arya

   University of Potsdam

   Affiliation as printed

   Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany

2. Maren Umlandt

   University of Potsdam

   Affiliation as printed

   Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany

3. Joachim Jelken

   University of Potsdam

   Affiliation as printed

   Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany

4. Nino Lomadze

   University of Potsdam

   Affiliation as printed

   Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany

5. Evgeny S. Asmolov

   Russian Academy of Sciences · Frumkin Institute of Physical Chemistry and Electrochemistry

   Affiliation as printed

   Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, Moscow, 119071, Russia

6. Olga I. Vinogradova corresponding Aachen DWI - Leibniz Institute for Interactive Materials

   Russian Academy of Sciences · Frumkin Institute of Physical Chemistry and Electrochemistry · DWI – Leibniz Institute for Interactive Materials

   Affiliation as printed

   DWI - Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, 52056, Aachen, Germany. oivinograd@yahoo.com

   Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, Moscow, 119071, Russia. oivinograd@yahoo.com

   Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, Moscow, 119071, Russia

7. Svetlana A. Santer corresponding

   University of Potsdam

   Affiliation as printed

   Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany. santer@uni-potsdam.de

   Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany