10.1021/acs.langmuir.9b00176.s006
Kei Yamaguchi
Kei
Yamaguchi
Eiji Yamamoto
Eiji
Yamamoto
Ryo Soma
Ryo
Soma
Bokusui Nakayama
Bokusui
Nakayama
Masashi Kuwahara
Masashi
Kuwahara
Toshiharu Saiki
Toshiharu
Saiki
Rapid Assembly of Colloidal Crystals under Laser Illumination
on a GeSbTe Substrate
American Chemical Society
2019
chalcogenide characteristics of
quasi-two-dimensional
chamber distance
chalcogenide phase-change material
laser intensity
Marangoni-like flow causes
crystal
GeSbTe Substrate Optical techniques
micrometer
2019-04-22 00:00:00
Media
https://acs.figshare.com/articles/media/Rapid_Assembly_of_Colloidal_Crystals_under_Laser_Illumination_on_a_GeSbTe_Substrate/8070143
Optical
techniques have been actively studied for manipulating
nano- to microsized objects. However, long-range attraction and rapid
transport of particles within thin quasi-two-dimensional systems are
difficult because of the weak thermophoretic forces. Here, we introduce
an experimental system that can rapidly generate quasi-two-dimensional
colloidal crystals in deionized water, sandwiched between two hard
plates. When a pulsed laser is irradiated on a chalcogenide phase-change
material spattered on one side of the plates, the induced Marangoni-like
flow causes a colloidal self-assembly in the order of tens of micrometers
within the laser spot, with a transport velocity of a few tens of
micrometers per second. This is due to the large thermal gradient
induced by chalcogenide characteristics of high laser absorption
and low thermal conductivity, and a strong hydrodynamic slip flow
at the hydrophobic chalcogenide interface. Moreover, the colloidal
crystals exhibit various lattice structures, depending on the laser
intensity and chamber distance. For a certain range of the chamber
distance, the colloidal crystal phases can be alternated by tuning
the laser intensity in real time. Our system forms and deforms quasi-two-dimensional
colloidal crystals at an on-demand location on a GeSbTe substrate.