3 research outputs found
Two-Dimensional Growth Rate Control of l‑Phenylalanine Crystal by Laser Trapping in Unsaturated Aqueous Solution
The
growth rate control of single l-phenylalanine plate-like
anhydrous crystal is successfully demonstrated by laser trapping at
an air/solution interface of the unsaturated aqueous solution. Focusing
a continuous-wave near-infrared laser beam into the interface generates
single l-phenylalanine crystal at the focal spot even under
unsaturated condition. Subsequently, the plane area of the generated
crystal becomes larger linearly with time under continued laser irradiation
into the crystal central part. Two-dimensional crystal growth rate
defined as a slope of the temporal change in the crystal plane area
strongly depends on initial solution concentration as well as irradiation
time until single crystal formation is confirmed by eye under a microscope.
When the laser power is decreased after the crystallization, the growth
rate is slowed down accordingly. Thus, the two-dimensional growth
rate is arbitrarily controlled by tuning the laser power. As the critical
phenomenon underlying the crystal growth, we propose that a dense
domain consisting of a large number of the liquid-like clusters is
formed prior to the crystallization. The dynamics and mechanism of
the two-dimensional crystal growth is discussed by considering the
supply of the solutes to the crystal edge from the cluster domain
dependent on the laser power