TY  - JOUR
A1  - Feldmann, David
A1  - Maduar, Salim R.
A1  - Santer, Mark
A1  - Lomadze, Nino
A1  - Vinogradova, Olga I.
A1  - Santer, Svetlana
T1  - Manipulation of small particles at solid liquid interface: light driven diffusioosmosis
T2  - Scientific reports
N2  - The strong adhesion of sub-micron sized particles to surfaces is a nuisance, both for removing contaminating colloids from surfaces and for conscious manipulation of particles to create and test novel micro/nano-scale assemblies. The obvious idea of using detergents to ease these processes suffers from a lack of control: the action of any conventional surface-modifying agent is immediate and global. With photosensitive azobenzene containing surfactants we overcome these limitations. Such photo-soaps contain optical switches (azobenzene molecules), which upon illumination with light of appropriate wavelength undergo reversible trans-cis photo-isomerization resulting in a subsequent change of the physico-chemical molecular properties. In this work we show that when a spatial gradient in the composition of trans-and cis-isomers is created near a solid-liquid interface, a substantial hydrodynamic flow can be initiated, the spatial extent of which can be set, e.g., by the shape of a laser spot. We propose the concept of light induced diffusioosmosis driving the flow, which can remove, gather or pattern a particle assembly at a solid-liquid interface. In other words, in addition to providing a soap we implement selectivity: particles are mobilized and moved at the time of illumination, and only across the illuminated area.
Y1  - 2016
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/44756
SN  - 2045-2322
VL  - 6
SP  - 25083
EP  - 25091
PB  - Nature Publ. Group
CY  - London
ER  -