Transcript KAUST Supercomputing Laboratory Orientation Session

Synthesis of Dispersed MetalOrganic Framework Crystals with
Controllable Size and Shape in
Aqueous Systems
Yichang Pan, Dodi Heryadi, Xiang Li, Lan Zhao, Gabriella
Lestari, Haibin Su, Zhiping Lai
Advanced Membranes and Porous Materials Center, King Abdullah University of
Science and Technology
Supercomputing Laboratory, King Abdullah University of Science and
Technology
Division of Materials Science, Nanyang Technological University, Singapore
Abstract
We demonstrated that surfactants like CTAB could efficiently
manipulate and control the shape and size of MOF (ZIF-8)
crystals. The reason is because the long hydrophobic hydrocarbon
chain of CTAB can adsorb on the hydrophobic surface of ZIF-8
crystals in aqueous solution and function as capping agent to slow
down the crystal growth rate. The growth rate of {100} decreased
much more profound than {110} and {111} faces because CTAB
molecules adsorbed on {100} much stronger than the other two
faces. Thus, not only the absolute value, but also the relative
growth rate of {100} to {110} decreased when more CTAB
molecules adsorbed on the surface. The present work may open a
facile method to control the shape and size of MOF particles that
may be very useful in their applications in membranes, optics and
building blocks for nano-device assembly, etc.
KAUST King Abdullah University of Science and Technology
XRD patterns and SEM images
a) XRD patterns, b-e) SEM images of ZIF8 crystals prepared with CTAB at the
amount of no CTAB, 0.0025%, 0.01% and
0.025%, respectively, f) plot of the mean
particle size of ZIF-8 crystals versus the
concentrations of CTAB added. The insets
in the SEM pictures are schematic
sketches of the crystal morphology. {110},
{100} and {111} facets are represented in
cyan, red and yellow color, respectively.
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SEM pictures of ZIF-8 crystals prepared by adding
TPABr and CTAC
SEM pictures of ZIF-8
crystals prepared by adding
TPABr and CTAC at the
amount of a) 0.001% TPABr,
b) 0.01% TPABr, c) 0.065%
TPABr, d) 0.0025% CTAC,
e) 0.01% CTAC, and f)
0.02% CTAC.
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predicted equilibrium morphology
a) The predicted equilibrium
morphology of ZIF-8 crystals
based on the minimum total
surface energy, b) the predicted
growth morphology based on the
attachment energies, and c) a
snapshot of the MD simulation of
CTAB molecules adsorbed on the
ZIF-8 {100} surface at 40 ps.
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Surface Free and Attachment Energies
Surface Free and Attachment Energies of Various Crystal Facets
Calculated Using the Morphology Module of the Material Studio.
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