Manipulation of small particles at solid liquid interface
- 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 inducedThe 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.…
Author details: | David FeldmannORCiDGND, Salim R. Maduar, Mark SanterORCiD, Nino Lomadze, Olga I. Vinogradova, Svetlana SanterORCiDGND |
---|---|
DOI: | https://doi.org/10.1038/srep36443 |
ISSN: | 2045-2322 |
Title of parent work (English): | Scientific reports |
Subtitle (English): | light driven diffusioosmosis |
Publisher: | Nature Publishing Group |
Place of publishing: | London |
Publication type: | Article |
Language: | English |
Date of first publication: | 2016/11/03 |
Publication year: | 2016 |
Publishing institution: | Universität Potsdam |
Release date: | 2016/12/01 |
Tag: | azobenzene; brushes; films; genomic DNA conformation; gradients; optical manipulation; photocontrol; photosensitive surfactants; tracking; transport |
Volume: | 6 |
Number of pages: | 10 |
Funding institution: | Universität Potsdam, Publikationsfonds |
Funding number: | PA 2016_39 |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Peer review: | Referiert |
Grantor: | Publikationsfonds der Universität Potsdam |
Publishing method: | Open Access |
License (German): | CC-BY - Namensnennung 4.0 International |
External remark: | Zweitveröffentlichung in der Schriftenreihe Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe ; 293 |