ACS Nano,
Год журнала:
2024,
Номер
18(37), С. 25512 - 25521
Опубликована: Сен. 5, 2024
Magnetic
fields
have
been
used
to
uniformly
align
the
lyotropic
chiral
nematic
(cholesteric)
liquid
crystalline
(LC)
phase
of
biopolymers
a
global
orientation
and
optical
appearance.
Here,
we
demonstrate
that,
in
contrast,
weak
patterned
magnetic
field
gradients
can
create
complex
appearance
with
variable
spatial
local
organization
needle-like
magnetically
decorated
cellulose
nanocrystals.
The
formation
optically
thin
films
left-
right-handed
achiral
regions
is
observed
related
gradient-driven
vortices
during
LC
suspension
flow.
We
trace
localized
flow
directions
nanocrystals
evaporation-induced
assembly,
demonstrating
how
competing
evaporation
field-induced
affect
twisted
within
induced
vortices.
simulations
suggested
that
twisting
inversion
originates
from
interplay
between
direction
strength
local-depth-related
receding
front
through
peripheral
gaps.
propose
this
finding
will
lead
photonic
films.
ACS Applied Optical Materials,
Год журнала:
2024,
Номер
2(12), С. 2540 - 2550
Опубликована: Ноя. 21, 2024
In
this
work,
twisted
helical
cellulose
nanocrystals
films
with
preprogrammed
circular
polarization
and
near-infrared
reflectance
are
fabricated
via
a
blade-based
3D
printing
method.
The
composed
of
stacked
nanoscale
slabs
high
birefringence
from
unidirectionally
organized
nanocrystals.
By
changing
the
director,
we
achieved
two
types
films:
stacks
anisotropic
Bragg
stacks.
These
highly
transparent
clear,
achiral
stack
shows
spectral
region
(1.3-1.4
μm).
contrast,
show
concurrent
left-
right-handed
circularly
polarized
properties,
as
opposed
to
left-handed
natural
films.
We
observe
dual
chiroptical
properties
dichroism
peaks
due
in
visible
suggest
that
extended
region.
observations
prompted
us
explore
transition
between
continuous
simulations.
printed
can
act
optical
metamaterials
helicity
fill
gap
known
photonic
structures-the
conventional
chiral
nematic
material
appearance
controlled
bandgap.
hold
potential
larger-scale
ordering
unique
nanostructures
for
polarized-sensitive
photonic,
thermal,
energy
management
applications.
Advanced Functional Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 23, 2025
Abstract
We
demonstrate
shear‐printed
layered
photonic
films
with
vivid
structural
coloration
from
bio‐derived
cellulose
nanocrystals
and
highly
aligned
Ti
3
C
2
T
x
MXene
nanoflakes.
These
ultrathin
(700–1500
nm)
show
high
light
transmittance
above
40%
in
the
visible
range.
In
reflectance
mode,
however,
appear
vividly
colored
iridescent
due
to
multiple
distinct
bandgaps
near‐infrared
ranges,
which
are
rarely
observed
CNC
composites.
The
is
controlled
by
stacking
of
nanoscale‐thin
layers
separated
thicker
matrix,
as
confirmed
simulations.
unique
combination
distinctly
different
optical
appearances
modes
occurs
printed
just
a
few
layers.
This
because
molecularly
smooth
interfaces
refractive
contrast
between
bio‐based
inorganic
phases,
result
concurrence
constructive
destructive
interference.
lamellar
biophotonic
open
possibilities
for
advanced
radiative
cooling,
camouflaging,
multifunctional
capacitors,
filtration
applications,
while
matrix
strengthens
their
flexibility,
robustness,
facilitates
sustainability.
Advanced Science,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 25, 2025
Abstract
Gravity
of
the
Earth
(
g
)
drives
macroscopic
differentiation
multiple
phases
with
different
volumetric
mass
densities
in
many
chemical
and
physical
processes.
Herein,
liquid
crystalline
phase
separation
colloidal
dispersions
rod‐shaped
cellulose
nanoparticles
centrifugal
acceleration
fields
up
to
71
061
meters
per
second
squared
(7251
is
studied.
Through
non‐ionic
situ
free‐radical
polymerization
initiated
by
time‐controllable
oxidation–reduction
reactions
between
tert‐butyl
hydroperoxide
(oxidants)
thiourea
(thiocarbamide,
reductants)
at
room
temperature
(298
kelvins),
ordered
soft
microstructures
formed
entropy‐driven
self‐assembly
are
immobilized
within
crosslinked
polyacrylamide
matrixes
various
evolution
stages
(e.g.,
after
10,
30,
or
60
min)
centrifuge
tubes.
Based
on
cross‐sectional
polarized
optical
scanning
electron
microscopy,
strong
accelerated
movement
velocity
discrete
tactoidal
microphases,
coalescence
tactoids
into
continuous
chiral
nematic
structures,
as
well
translational
rotational
relaxation
rates
mesogenic
nanorods
kinetically
arrested
states
high‐viscosity
concentrated
crystals,
leading
elimination
topological
defects
improvements
structural
orderliness.
Since
indistinguishable
from
a
homogeneous
gravitational
field
according
Einstein's
principle
equivalence
general
relativity,
these
results
might
help
predict
self‐assembling
behaviors
near
compact
astrophysical
objects
such
neutron
stars.
Advanced Optical Materials,
Год журнала:
2024,
Номер
unknown
Опубликована: Авг. 31, 2024
Abstract
The
self‐assembled
cellulose
nanocrystal
(CNC)
film
has
a
left‐handed
layered
structure,
which
makes
the
reflection
of
right‐handed
circularly
polarized
(CP)
light
challenge.
Herein,
nematic
phase
layer
is
designed
and
inserted
into
chiral
organization,
to
work
as
half‐wave
retarder
make
ambidextrous
CP
reflection.
maximum
reflectivity
exceeds
80%,
breaks
50%
limitations
single‐direction
current
in
all
reported
CNC‐based
films.
This
“sandwich‐like”
structure
displays
different
optical
properties
on
both
sides,
displayed
chromatism
inversion
circular
dichroism
signals.
dual
direction‐dependent
phenomena
are
reserved
synthesized
luminescence
(CPL)
film,
with
dissymmetry
factor
(
g
lum
)
−0.4245.
However,
this
luminescent
intensity
emission
not
enough
advanced
systems.
designs
triple
CPL
amplification
path
develops
handedness
strategy,
−1.0551
0.4082.
Then,
dual‐directional
films
designed,
where
optics
can
be
switched
on‐demand.
Finally,
photonic
crystal
applied
anti‐counterfeit
superstructure
induction.
Chiral
microlasers
hold
great
promise
for
optoelectronics
from
integrated
photonic
devices
to
high-density
quantum
information
processing.
Despite
significant
progress
in
lead-halide
perovskite
emitters,
chiral
lasing
with
high
dissymmetry
factors
(
Abstract
Currently,
circularly
polarized
luminescence
(CPL)
has
drawn
wide
interest
in
3D
display,
information
storage,
and
optical
sensing.
However,
traditional
synthetic
paths
are
often
accompanied
by
low
chiral
intensity
complex
processes.
Cellulose
nanocrystals
(CNCs),
with
the
properties
of
liquid
crystals,
can
spontaneously
arrange
into
left‐handed
layered
nanofilm,
which
enables
them
candidates
construction
CPL
materials.
Following
this
approach,
work
reviews
synthesis
cellulose‐based
luminescent
The
co‐assembly
technique,
situ
intercalation
strategy,
defect
destruction
design
efficient
encapsulating
luminophores
CNC
organization.
Next,
various
strategies
on
regulation,
including
matching
photonic
bandgap,
pathway
design,
tailored
helical
structure,
summarized.
These
offer
new
sights
control,
mainly
focusing
amplification
inversion
signals.
Multimodal
convertible
chiroptical
signals
enable
films
practical
values
anti‐counterfeit,
sensing,
handedness
induction.
Overall,
timely
overview
summarizes
synthesis,
application
materials,
aims
to
inspire
development
