2 research outputs found
Hierarchical Striped Walls Constructed by the Photopolymerization of Discotic Reactive Building Blocks in the Anisotropic Liquid Crystal Solvents
A triphenylene-based
reactive mesogenic molecule (abbreviated as
HABET) was newly designed and synthesized as a programmed building
block to construct the striped walls by the photopolymerization in
the anisotropic liquid crystal (LC) solvents. On the basis of thermal,
scattering and microscopic analyses, it was found that HABET formed
three ordered structures: a columnar hexagonal LC phase (Φ<sub>H</sub>), a tilted columnar hexagonal LC phase (Φ<sub>T</sub>) and a highly ordered columnar oblique crystal phase (Φ<sub>OK</sub>). The microscopic molecular orientations in the hierarchical
superstructures were controlled in the anisotropic LC solvents with
the help of surface anchoring forces, while the dimensions of the
striped wall morphologies were determined by the patterned photomasks.
The long axis of self-assembled columns in the striped walls was perpendicular
to the surface alignment direction regardless of the photomask direction.
Additionally, it was realized that the shapes of water drops as well
as the surface water contact angles can be tuned by the hierarchical
superstructures and morphologies of the polymerized HABET networks.
The anisotropic hierarchical superstructures and morphologies concurrently
fabricated during the polymerization in the anisotropic LC medium
can offer a potential pathway for liquid transportation in the microfluidic
devices
Flexible and Patterned Thin Film Polarizer: Photopolymerization of Perylene-based Lyotropic Chromonic Reactive Mesogens
A perylene-based reactive mesogen
(DAPDI) forming a lyotropic chromonic liquid crystal (LCLC) phase
was newly designed and synthesized for the fabrication of macroscopically
oriented and patterned thin film polarizer (TFP) on the flexible polymer
substrates. The anisotropic optical property and molecular self-assembly
of DAPDI were investigated by the combination of microscopic, scattering
and spectroscopic techniques. The main driving forces of molecular
self-assembly were the face-to-face π–π intermolecular
interaction among aromatic cores and the nanophase separation between
hydrophilic ionic groups and hydrophobic aromatic cores. Degree of
polarization for the macroscopically oriented and photopolymerized
DAPDI TFP was estimated to be 99.81% at the <i><b>λ</b></i><sub>max</sub> = 491 nm. After mechanically shearing the
DAPDI LCLC aqueous solution on the flexible polymer substrates, we
successfully fabricated the patterned DAPDI TFP by etching the unpolymerized
regions selectively blocked by a photomask during the photopolymerization
process. Chemical and mechanical stabilities were confirmed by the
solvent and pencil hardness tests, and its surface morphology was
further investigated by optical microscopy, atomic force microscopy,
and three-dimensional surface nanoprofiler. The flexible and patterned
DAPDI TFP with robust chemical and mechanical stabilities can be a
stepping stone for the advanced flexible optoelectronic devices