18 research outputs found
Data File 4: Chiral hydrogen-bonded complex with different mesogens length and its effect on the performances of blue phase
Phase-transition and BP range of the LC mixture doped with H-bonded complexes Originally published in Optical Materials Express on 01 March 2016 (ome-6-3-868
Dual-Band Modulation of Visible and Near-Infrared Light Transmittance in an All-Solution-Processed Hybrid Micro–Nano Composite Film
Smart
windows with controllable visible and near-infrared light transmittance
can significantly improve the building’s energy efficiency
and inhabitant comfort. However, most of the current smart window
technology cannot achieve the target of ideal solar control. Herein,
we present a novel all-solution-processed hybrid micronano composite
smart material that have four optical states to separately modulate
the visible and NIR light transmittance through voltage and temperature,
respectively. This dual-band optical modulation was achieved by constructing
a phase-separated polymer framework, which contains the microsized
liquid crystals domains with a negative dielectric constant and tungsten-doped
vanadium dioxide (W-VO<sub>2</sub>) nanocrystals (NCs). The film with
2.5 wt % W-VO<sub>2</sub> NCs exhibits transparency at normal condition,
and the passage of visible light can be reversibly and actively regulated
between 60.8% and 1.3% by external applied voltage. Also, the transmittance
of NIR light can be reversibly and passively modulated between 59.4%
and 41.2% by temperature. Besides, the film also features easy all-solution
processability, fast electro-optical (E-O) response time, high mechanical
strength, and long-term stability. The as-prepared film provides new
opportunities for next-generation smart window technology, and the
proposed strategy is conductive to engineering novel hybrid inorganic–organic
functional matters
Effects of thiophene-based mesogen terminated with branched alkoxy group on the temperature range and electro-optical performances of liquid crystalline blue phases
<p>A series of symmetrically thiophene-based bent-shaped molecules with branched terminal was synthesised and characterised. Then, their effects as dopants on the blue phase (BP) range of the chiral nematic liquid crystal (N*LC) host were investigated. It was found that the bent-shaped dopants with branched terminal had better miscibility in LC host than the bent-shaped dopants with straight terminal, and contributed to induce BP and enhance the BP temperature range, with the maximum BP temperature range about 20.4°C. Besides, the electro-optical (E-O) performances of the blue phase liquid crystal doped with Th-BC6 (a bent-shaped dopant with the widest induced BP range in N*LC) were also explored. It was found that the drive voltage reduced first and then increased with the doping amount of Th-BC6 increasing. When the doping amount of Th-BC6 was about 15 wt%, the hysteresis could be strikingly reduced.</p
A Facile All-Solution-Processed Surface with High Water Contact Angle and High Water Adhesive Force
A series
of sticky superhydrophobicity surfaces with high water
contact angle and high water adhesive force is facilely prepared via
an all-solution-processed method based on polymerization-induced phase
separation between liquid crystals (LCs) and epoxy resin, which produces
layers of epoxy microspheres (EMSs) with nanofolds on the surface
of a substrate. The morphologies and size distributions of EMSs are
confirmed by scanning electron microscopy. Results reveal that the
obtained EMS coated-surface exhibits high apparent contact angle of
152.0° and high water adhesive force up to 117.6 μN. By
varying the composition of the sample or preparing conditions, the
sizes of the produced EMSs can be artificially regulated and, thus,
control the wetting properties and water adhesive behaviors. Also,
the sticky superhydrophobic surface exhibits excellent chemical stability,
as well as long-term durability. Water droplet transportation experiments
further prove that the as-made surface can be effectively used as
a mechanical hand for water transportation applications. Based on
this, it is believed that the simple method proposed in this paper
will pave a new way for producing a sticky superhydrophobic surface
and obtain a wide range of use
Elastomeric Conducting Polyaniline Formed Through Topological Control of Molecular Templates
A strategy for creating
elastomeric conducting polyaniline networks
is described. Simultaneous elastomeric mechanical properties (<i>E</i> < 10 MPa) and electronic conductivities (σ >
10 S cm<sup>–1</sup>) are achieved <i>via</i> molecular
templating of conjugated polymer networks. Diblock copolymers with
star topologies processed into self-assembled elastomeric thin films
reduce the percolation threshold of polyaniline synthesized <i>via in situ</i> polymerization. Block copolymer templates with
star topologies produce elastomeric conjugated polymer composites
with Young’s moduli ranging from 4 to 12 MPa, maximum elongations
up to 90 ± 10%, and electrical conductivities of 30 ± 10
S cm<sup>–1</sup>. Templated polyaniline films exhibit Young’s
moduli up to 3 orders of magnitude smaller compared to bulk polyaniline
films while preserving comparable bulk electronic conductivity. Flexible
conducting polymers have prospective applications in devices for energy
storage and conversion, consumer electronics, and bioelectronics
Photoresponsive iodine-bonded liquid crystals based on azopyridine derivatives with a low phase-transition temperature
<p>Halogen bonding interactions in the formation of liquid crystalline phases have been recognised in recent years. Here, we report a novel series of iodine-bonded liquid crystals using 1,2-diiodotetrafluorobenzene (1,2-DITFB) and azopyridine derivatives (AnAzPy), showing a smectic A phase and concurrent photoresponsive behaviour. These were characterised by using a polarising optical microscope, differential scanning calorimetry and UV-vis absorption spectroscopy. The formation of iodine bonding in the complexes was confirmed by X-ray photoelectron spectroscopy and Raman spectroscopy. Importantly, these iodine-bonded complexes demonstrated a low liquid crystal temperature range (30–50°C) among those reported for photoresponsive halogen-bonded liquid crystals. The molar ratio of the iodine-bonded donor and acceptor was 1:1 upon the self-assembly of the supramolecular complex molecule, as indicated by 1D-WAXD experiments of mixed samples of 1,2-DITFB and AnAzPy with different molar ratios. This study offers a new family of photoresponsive halogen-bonded liquid crystals and broadens the potential applications in their associated systems.</p
Additional file 2: Figure S2. of Characterization of four vaccine-related polioviruses including two intertypic type 3/type 2 recombinants associated with aseptic encephalitis
Phylogenetic trees based on 3D genomic regions of HEV-C generated by the neighbor-joining algorithm implemented in MEGA (version 6.06) using the Kimura two-parameter substitution model and 1,000 bootstrap pseudo-replicates. â˛strains isolated in this investigation; â other PV3 strains. (DOC 682 kb
Hyperbranched Polyester Hydrogels with Controlled Drug Release and Cell Adhesion Properties
Hyperbranched
polyesters (HPE) have a high efficiency to encapsulate
bioactive agents, including drugs, genes, and proteins, due to their
globe-like nanostructure. However, the use of these highly branched
polymeric systems for tissue engineering applications has not been
broadly investigated. Here, we report synthesis and characterization
of photocrosslinkable HPE hydrogels with sustained drug release characteristics
for cellular therapies. These HPE can encapsulate hydrophobic drug
molecules within the HPE cavities due to the presence of a hydrophobic
inner structure that is otherwise difficult to achieve in conventional
hydrogels. The functionalization of HPE with photocrosslinkable acrylate
moieties renders the formation of hydrogels with a highly porous interconnected
structure and mechanically tough network. The compressive modulus
of HPE hydrogels was tunable by changing the crosslinking density.
The feasibility of using these HPE networks for cellular therapies
was investigated by evaluating cell adhesion, spreading, and proliferation
on hydrogel surface. Highly crosslinked and mechanically stiff HPE
hydrogels have higher cell adhesion, spreading, and proliferation
compared to soft and complaint HPE hydrogels. Overall, we showed that
hydrogels made from HPE could be used for biomedical applications
that require spatial control of cell adhesion and controlled release
of hydrophobic clues
Biologically Derived Soft Conducting Hydrogels Using Heparin-Doped Polymer Networks
The emergence of flexible and stretchable electronic components expands the range of applications of electronic devices. Flexible devices are ideally suited for electronic biointerfaces because of mechanically permissive structures that conform to curvilinear structures found in native tissue. Most electronic materials used in these applications exhibit elastic moduli on the order of 0.1–1 MPa. However, many electronically excitable tissues exhibit elasticities in the range of 1–10 kPa, several orders of magnitude smaller than existing components used in flexible devices. This work describes the use of biologically derived heparins as scaffold materials for fabricating networks with hybrid electronic/ionic conductivity and ultracompliant mechanical properties. Photo-cross-linkable heparin–methacrylate hydrogels serve as templates to control the microstructure and doping of <i>in situ</i> polymerized polyaniline structures. Macroscopic heparin-doped polyaniline hydrogel dual networks exhibit impedances as low as <i>Z</i> = 4.17 Ω at 1 kHz and storage moduli of <i>G</i>′ = 900 ± 100 Pa. The conductivity of heparin/polyaniline networks depends on the oxidation state and microstructure of secondary polyaniline networks. Furthermore, heparin/polyaniline networks support the attachment, proliferation, and differentiation of murine myoblasts without any surface treatments. Taken together, these results suggest that heparin/polyaniline hydrogel networks exhibit suitable physical properties as an electronically active biointerface material that can match the mechanical properties of soft tissues composed of excitable cells
Preparation of a Thermally Light-Transmittance-Controllable Film from a Coexistent System of Polymer-Dispersed and Polymer-Stabilized Liquid Crystals
Polymer-dispersed
liquid crystal (PDLC) and polymer-stabilized
liquid crystal (PSLC) systems are the two primary distinct systems
in the field of liquid crystal (LC) technology, and they are differentiated
by their unique microstructures. Here, we present a novel coexistent
system of polymer-dispersed and polymer-stabilized liquid crystals
(PD&SLCs), which forms a homeotropically aligned polymer network
(HAPN) within the LC droplets after a microphase separation between
the LC and polymer matrix and combines the advantages of both the
PDLC and PSLC systems. Then, we prepare a novel thermally light-transmittance-controllable
(TLTC) film from the PD&SLC system, where the transmittance can
be reversibly changed through thermal control from a transparent to
a light-scattering state. The film also combines the advantageous
features of flexibility and a potential for large-scale manufacturing,
and it shows significant promise in future applications from smart
windows to temperature sensors