10.1021/acs.langmuir.6b04532.s006
Jun Nozawa
Jun
Nozawa
Satoshi Uda
Satoshi
Uda
Suxia Guo
Suxia
Guo
Sumeng Hu
Sumeng
Hu
Akiko Toyotama
Akiko
Toyotama
Junpei Yamanaka
Junpei
Yamanaka
Junpei Okada
Junpei
Okada
Haruhiko Koizumi
Haruhiko
Koizumi
Two-Dimensional Nucleation on the Terrace of Colloidal
Crystals with Added Polymers
American Chemical Society
2017
2 D nucleation rate
growth stage
2 D nucleation process
area fractions
nucleation dynamics
materials science
nuclei form
nucleation rate
ϕ area
kink sites
energy barrier
growth mechanism
Two-Dimensional Nucleation
nucleation behavior
nucleation pathway
single-particle resolution
nucleation theory
nucleation process
Colloidal Crystals
CNT
particle interaction
Characteristic nucleation behavior
γ value
2017-03-16 00:00:00
Media
https://acs.figshare.com/articles/media/Two-Dimensional_Nucleation_on_the_Terrace_of_Colloidal_Crystals_with_Added_Polymers/4776511
Understanding nucleation dynamics
is important both fundamentally and technologically in materials science
and other scientific fields. Two-dimensional (2D) nucleation is the
predominant growth mechanism in colloidal crystallization, in which
the particle interaction is attractive, and has recently been regarded
as a promising method to fabricate varieties of complex nanostructures
possessing innovative functionality. Here, polymers are added to a
colloidal suspension to generate a depletion attractive force, and
the detailed 2D nucleation process on the terrace of the colloidal
crystals is investigated. In the system, we first measured the nucleation
rate at various area fractions of particles on the terrace, ϕ<sub>area</sub>. In situ observations at single-particle resolution revealed
that nucleation behavior follows the framework of classical nucleation
theory (CNT), such as single-step nucleation pathway and existence
of critical size. Characteristic nucleation behavior is observed in
that the nucleation and growth stage are clearly differentiated. When
many nuclei form in a small area of the terrace, a high density of
kink sites of once formed islands makes growth more likely to occur
than further nucleation because nucleation has a higher energy barrier
than growth. The steady-state homogeneous 2D nucleation rate, <i>J</i>, and the critical size of nuclei, <i>r</i>*,
are measured by in situ observations based on the CNT, which enable
us to obtain the step free energy, γ, which is an important
parameter for characterizing the nucleation process. The γ value
is found to change according to the strength of attraction, which
is tuned by the concentration of the polymer as a depletant.