Optothermal Actuation of Unidirectional Thermo-osmotic Flows

Tetsuro Tsuji; Shota Suzuki; Satoshi Taguchi; Haruya Ishida; Hideaki Teshima

Optothermal Actuation of Unidirectional Thermo-osmotic Flows

Fluid Dynamics 2026-06-26 v1 Applied Physics

Authors: Tetsuro Tsuji , Shota Suzuki , Satoshi Taguchi , Haruya Ishida , Hideaki Teshima

Abstract

In this paper, we experimentally demonstrate the microscale direction control of thermoosmotic flows using a focused-laser heating. The key is the off-center laser irradiation on an immobilized light-absorbing microparticle, which generates a nonuniform, asymmetric heat source. The resulting thermo-osmotic flows are evaluated using the optically trapped particle tracking velocimetry (ot-PTV), presented in our preceding paper (T. Tsuji, et al., Physical Review Fluids 11, 034901 (2026)). It is shown that the flow characteristics can be modulated by the ionic strength of a sample solution and/or the surface molecular coating of the substrate. In particular, the significance of ionic strength on thermo-osmotic flows are discussed based on the surface potential of the substrate measured by frequency-modulated atomic force microscopy.

Keywords

thermo-osmotic flows focused-laser heating microscale flow control particle tracking velocimetry ionic strength surface potential atomic force microscopy

Cite

@article{arxiv.2606.27735,
  title  = {Optothermal Actuation of Unidirectional Thermo-osmotic Flows},
  author = {Tetsuro Tsuji and Shota Suzuki and Satoshi Taguchi and Haruya Ishida and Hideaki Teshima},
  journal= {arXiv preprint arXiv:2606.27735},
  year   = {2026}
}

Comments

10 pages, 10 figures