2 research outputs found
Mechanistic Insight into the Synthesis of Silica-Based “Matchstick” Colloids
We
report an insight into the synthesis of silica-based “matchstick”-shaped
colloidal particles, which are of interest in the area of self-propulsion
on small length scales. The generation of aqueous emulsion droplets
dispersed in an <i>n</i>-pentanol-rich continuous phase
and their use as reaction centers allows for the fabrication of siliceous
microparticles that exhibit anisotropy in both particle morphology,
that is, a “matchstick” shape, and chemistry, that is,
a transition-metal oxide-enriched head. We provide a series of kinetic
studies to gain a mechanistic understanding and unravel the particle
formation and growth processes. Additionally, we demonstrate the ability
to select the aspect ratio of the “matchstick” particle
in a straightforward manner
Resolving the Nanoscale Morphology and Crystallographic Structure of Molecular Thin Films: F<sub>16</sub>CuPc on Graphene Oxide
Electron microscopy and diffraction are used to examine
the nanoscale structure and molecular orientation in molecular films
down to nominally monolayer thickness. The films studied consist of
the planar n-type molecular semiconductor copper hexadecafluorophthalocyanine
(F<sub>16</sub>CuPc) directly deposited onto graphene oxide (GO) membranes
by organic molecular beam deposition. The graphene oxide support crucially
provides the strength and low background required to analyze the crystal
structure and morphology of even nominally monolayer thick films and
is of relevance for molecular electronic applications. The crystal
structure of the F<sub>16</sub>CuPc polymorph is solved by X-ray diffraction
of single crystals and used to analyze the electron diffraction patterns
from the thin-films, revealing that the F<sub>16</sub>CuPc molecules
assemble with their molecular plane oriented perpendicular to the
GO. There is no evidence for changes in the unit cell with film thickness,
although the thinnest films show the greatest disorder in molecular
packing. Direct deposition of molecular materials on low contrast
and relevant substrates combined with electron and scanning probe
microscopy is thus shown to be a powerful technique for elucidating
structure in nanostructured organic thin films