TY  - JOUR
A1  - Muraveva, Valeriia
A1  - Bekir, Marek
A1  - Lomadze, Nino
A1  - Großmann, Robert
A1  - Beta, Carsten
A1  - Santer, Svetlana
T1  - Interplay of diffusio- and thermo-osmotic flows generated by single light stimulus
T2  - Applied physics letters
N2  - Flow control is a highly relevant topic for micromanipulation of colloidal particles in microfluidic applications. Here, we report on a system that combines two-surface bound flows emanating from thermo-osmotic and diffusio-osmotic mechanisms. These opposing flows are generated at a gold surface immersed into an aqueous solution containing a photo-sensitive surfactant, which is irradiated by a focused UV laser beam. At low power of incoming light, diffusio-osmotic flow due to local photo-isomerization of the surfactant dominates, resulting in a flow pattern oriented away from the irradiated area. In contrast, thermo-osmotic flow takes over due to local heating of the gold surface at larger power, consequently inducing a flow pointing toward the hotspot. In this way, this system allows one to reversibly switch from outward to inward liquid flow with an intermittent range of zero flow at which tracer particles undergo thermal motion by just tuning the laser intensity only. Our work, thus, demonstrates an optofluidic system for flow generation with a high degree of controllability that is necessary to transport particles precisely to desired locations, thereby opening innovative possibilities to generate advanced microfluidic applications.
Y1  - 2022
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/56973
SN  - 0003-6951
SN  - 1077-3118
VL  - 120
IS  - 23
PB  - American Institute of Physics
CY  - Melville
ER  -