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ID 113996
Author
Chikazawa, Jun-ichi University of Tokushima
Uwada, Takayuki Josai University
Content Type
Journal Article
Description
Optothermal trapping has gained increasing popularity in manipulation such as selecting, guiding, and positioning submicron objects because of a few mW laser power much lower than that required for optical trapping. The optotothermal trapping uses thermal gradient-induced phoretic motions, but the underlying physics of driving force has not been fully understood. In this study, we performed optotothermal trapping of 500-nm-diameter colloidal silica via a continuous laser illumination of a single gold nanoparticle from the bottom in a closed chamber. Under illumination, the tracer particles were attracted to the gold nanoparticle and trapped. Notably, the direction of migrating particles was always to hot gold nanoparticle regardless of the configuration of gold nanoparticle placed at two opposite sides of the chamber, on the bottom surface of an upper substrate (ceiling) or on the top surface of a lower substrate (floor). The previous interpretation based on thermal convective flow from the bottom to the top and circulating inside the chamber was only applicable to floor configuration and failed to explain our observation for ceiling. Instead, temperature-induced Marangoni effect at the water/superheated water interface is likely to play a role. This study promoted a better understanding of the driving mechanism in optothermal trapping. Moreover, as an application of the single-particle platform, we showed the photothermal phase separation-induced microdroplet formation of thermoresponsive polymers and the coating of non-thermoresponsive polymers on nanoparticles.
Journal Title
The Journal of Physical Chemistry C
ISSN
19327447
19327455
NCID
AA1217589X
AA12192210
Publisher
ACS Publications
Volume
123
Issue
7
Start Page
4512
End Page
4522
Published Date
2019-01-26
Rights
This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.jpcc.8b11575.
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DOI (Published Version)
URL ( Publisher's Version )
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language
eng
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departments
Science and Technology