Transparent nanocellulose paper-based biodegradable colorimetric nerve agent detectors.

Transparent cellulose nanofiber (t-CNF) films were prepared by succinylation and an aqueous collision counter system treatment, and used for the colorimetric detection of diethyl chlorophosphate (DCP), a nerve agent mimic in the vapor phase. DCP receptor with an oxime residue was anchored on the surface of succinylated CNF films, resulting in the target probe (CNF-Azo films). CNF-Azo films exhibited selective detection behavior toward DCP in the vapor phase.

Large-area transparent biocomposite films based on nanocellulose and nanochitin via horizontal centrifugal casting.

In this study, we introduce the horizontal centrifugal casting (HCC) process that enables centrifugal force-assisted, scalable production of large-area (10 in.) polymer composite films based on nanocellulose (CNF) and nanochitin (ChNF). The HCC employs a cylinder mold with its rotation pivot being in a horizontal posture to harness centrifugal force to help flatten the film being cast, from which polymer composite films with excellent uniformity and flatness can be reliably produced in the size of the lateral surface of the cylinder mold.

3D Heterogeneous Device Arrays for Multiplexed Sensing Platforms Using Transfer of Perovskites.

Despite recent substantial advances in perovskite materials, their 3D integration capability for next-generation electronic devices is limited owing to their inherent vulnerability to heat and moisture with degradation of their remarkable optoelectronic properties during fabrication processing. Herein, a facile method to transfer the patterns of perovskites to planar or nonplanar surfaces using a removable polymer is reported. After fabricating perovskite devices on this removable polymer film, the conformal attachment of this film on target surfaces can place the entire devices on various substrates by removing this sacrificial film.

Flexible Transparent Crystalline-ITO/Ag Nanowire Hybrid Electrode with High Stability for Organic Optoelectronics.

Metal nanowires (NWs) are promising transparent conducting electrode (TCE) materials because of their excellent optoelectrical performance, intrinsic mechanical flexibility, and large-scale processability. However, the surface roughness, thermal/chemical instability, and limited electrical conductivity associated with empty spaces between metal NWs are problems that are yet to be solved. Here, we report a highly reliable and robust composite TCE/substrate all-in-one platform that consists of crystalline indium tin oxide (c-ITO) top layer and surface-embedded metal NW (c-ITO/AgNW-GFRH) films for flexible optoelectronics.

Transparent, water-stable, cellulose nanofiber-based packaging film with a low oxygen permeability.

Herein, we report on a transparent, water-stable, high oxygen barrier packaging film made from a combination of cellulose nanofiber (CNF) and a fluoropolymer (FP) coating. Nanofibrillation of the hardwood kraft pulp was carried out using succinic anhydride pretreatment and aqueous counter collision (ACC) technique to obtain ultrafine (5-7 nm) succinylated cellulose nanofibers (SCNF), which was readily fabricated into a thin coating (on PET film) as well as a self-standing film. Introducing the FP topcoat on SCNF enabled a synergistic enhancement of both oxygen barrier performance and stability against water-swelling.

Tailored Poly(vinylidene fluoride--trifluoroethylene) Crystal Orientation for a Triboelectric Nanogenerator through Epitaxial Growth on a Chitin Nanofiber Film.

Tailoring the crystal orientation of poly(vinylidene fluoride--trifluoroethylene) (PVDF-TrFE) has attracted widespread interest because of its effects on the ferroelectric properties required for various electronic devices. In this study, we investigated the epitaxial growth of PVDF-TrFE on a chitin film for developing triboelectric nanogenerators (TENGs). The crystallographic match between the chitin and PVDF-TrFE enables the development of the intended crystal orientation, with the PVDF-TrFE polarization axis aligned perpendicular to the substrate.

Optically Transparent Multiscale Composite Films for Flexible and Wearable Electronics.

One of the key breakthroughs enabling flexible electronics with novel form factors is the deployment of flexible polymer films in place of brittle glass, which is one of the major structural materials for conventional electronic devices. Flexible electronics requires polymer films with the core properties of glass (i.e.

Bioinspired Transparent Laminated Composite Film for Flexible Green Optoelectronics.

Herein, we report a new version of a bioinspired chitin nanofiber (ChNF) transparent laminated composite film (HCLaminate) made of siloxane hybrid materials (hybrimers) reinforced with ChNFs, which mimics the nanofiber-matrix structure of hierarchical biocomposites. Our HCLaminate is produced via vacuum bag compressing and subsequent UV-curing of the matrix resin-impregnated ChNF transparent paper (ChNF paper). It is worthwhile to note that this new type of ChNF-based transparent substrate film retains the strengths of the original ChNF paper and compensates for ChNF paper's drawbacks as a flexible transparent substrate.

Hierarchical Chitin Fibers with Aligned Nanofibrillar Architectures: A Nonwoven-Mat Separator for Lithium Metal Batteries.

Here, we introduce regenerated fibers of chitin (Chiber), the second most abundant biopolymer after cellulose, and propose its utility as a nonwoven fiber separator for lithium metal batteries (LMBs) that exhibits an excellent electrolyte-uptaking capability and Li-dendrite-mitigating performance. Chiber is produced by a centrifugal jet-spinning technique, which allows a simple and fast production of Chibers consisting of hierarchically aligned self-assembled chitin nanofibers. Following the scrutinization on the Chiber-Li-ion interaction via computational methods, we demonstrate the potential of Chiber as a nonwoven mat-type separator by monitoring it in Li-O and Na-O cells.

Flexible Hard Coating: Glass-Like Wear Resistant, Yet Plastic-Like Compliant, Transparent Protective Coating for Foldable Displays.

A flexible hard coating for foldable displays is realized by the highly cross-linked siloxane hybrid using structure-property relationships in organic-inorganic hybridization. Glass-like wear resistance, plastic-like flexibility, and highly elastic resilience are demonstrated together with outstanding optical transparency. It provides a framework for the application of siloxane hybrids in protective hard coatings with high scratch resistance and flexibility for foldable displays.

A Flexible and Robust Transparent Conducting Electrode Platform Using an Electroplated Silver Grid/Surface-Embedded Silver Nanowire Hybrid Structure.

In this paper, we report flexible transparent conducting electrode (TCE) film using a silver grid (Ag grid)/silver nanowire (AgNW) hybrid structure (AG/NW-GFRHybrimer). The AG/NW-GFRHybrimer consists of an AgNW-embedded glass-fabric reinforced plastic film (AgNW-GFRHybrimer) and an electroplated Ag grid. The AgNW-GFRHybrimer is used as a flexible transparent substrate and a seed layer for electroplating.

Chitin Nanofiber Transparent Paper for Flexible Green Electronics.

A transparent paper made of chitin nanofibers (ChNF) is introduced and its utilization as a substrate for flexible organic light-emitting diodes is demonstrated. Given its promising macroscopic properties, biofriendly characteristics, and availability of the raw material, the utilization of the ChNF transparent paper as a structural platform for flexible green electronics is envisaged.

Squid beak inspired water processable chitosan composites with tunable mechanical properties.

Natural biological composites often couple light weight with tunable and spatially controlled mechanical properties including stiffness, toughness, and hardness. Examples include the toughness of seashells, the hardness of the chiton tooth, and the stiffness gradient of the squid beak. While seashells and the chiton tooth have a mineralized inorganic component, the squid beak is entirely organic.

A high-performance, flexible and robust metal nanotrough-embedded transparent conducting film for wearable touch screen panels.

We report a high-performance, flexible and robust metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using an electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded on the surface of a glass-fabric reinforced composite substrate (GFRHybrimer).

Ultraviolet light stable and transparent sol-gel methyl siloxane hybrid material for UV light-emitting diode (UV LED) encapsulant.

An ultraviolet (UV) transparent and stable methyl-siloxane hybrid material was prepared by a facile sol-gel method. The transparency and stability of a UV-LED encapsulant is an important issue because it affects UV light extraction efficiency and long-term reliability. We introduced a novel concept for UV-LED encapsulation using a thermally curable oligosiloxane resin.

Flexible transparent conducting hybrid film using a surface-embedded copper nanowire network: a highly oxidation-resistant copper nanowire electrode for flexible optoelectronics.

We report a flexible high-performance conducting film using an embedded copper nanowire transparent conducting electrode; this material can be used as a transparent electrode platform for typical flexible optoelectronic devices. The monolithic composite structure of our transparent conducting film enables simultaneously an outstanding oxidation stability of the copper nanowire network (14 d at 80 °C), an exceptionally smooth surface topography (R(rms) < 2 nm), and an excellent opto-electrical performances (Rsh = 25 Ω sq(-1) and T = 82%). A flexible organic light emitting diode device is fabricated on the transparent conducting film to demonstrate its potential as a flexible copper nanowire electrode platform.

Mechanical properties of self-assembled chitin nanofiber networks.

Chitin nanofibers are structural components of the insect cuticle, the exoskeleton of crabs, and mollusk shells. Chitin nanofibers have found broad use in biomedical applications. Here, we study structure-properties-processing relationships of 3 nm chitin nanofiber networks self-assembled from a chitin hexafluoroisopropanol solution.

Sol-gel derived transparent zirconium-phenyl siloxane hybrid for robust high refractive index LED encapsulant.

We report a zirconium-phenyl siloxane hybrid material (ZPH) that can be used as a robust LED encapsulant. The ZPH encapsulant was fabricated via hydrosilylation-curing of sol-gel derived multifunctional (vinyl- and hydride-functions) siloxane resins containing phenyl-groups and Zr-O-Si heterometallic phase for achieving a high refractive index (n ≈ 1.58).

Flexible transparent conducting composite films using a monolithically embedded AgNW electrode with robust performance stability.

We report on the performance of an all-in-one flexible hybrid conducting film employing a monolithically embedded AgNW transparent electrode and a high-performance glass-fabric reinforced composite substrate (AgNW-GFRHybrimer film). Specifically, we perform in-depth investigations on the stability of the AgNW-GFRHybrimer film against heat, thermal oxidation, and wet chemicals to demonstrate the potential of the hybrid conducting film as a robust electrode platform for thin-film optoelectronic devices. With the ease of large-area processability, smooth surface topography, and robust performance stability, the AgNW-GFRHybrimer film can be a promising platform for high-performance optoelectronic devices.

Chitin Nanofiber Micropatterned Flexible Substrates for Tissue Engineering.

Engineered tissues require enhanced organization of cells and extracellular matrix (ECM) for proper function. To promote cell organization, substrates with controlled micro- and nanopatterns have been developed as supports for cell growth, and to induce cellular elongation and orientation via contact guidance. Micropatterned ultra-thin biodegradable substrates are desirable for implantation in the host tissue.

H+-type and OH- -type biological protonic semiconductors and complementary devices.

Proton conduction is essential in biological systems. Oxidative phosphorylation in mitochondria, proton pumping in bacteriorhodopsin, and uncoupling membrane potentials by the antibiotic Gramicidin are examples. In these systems, H(+) hop along chains of hydrogen bonds between water molecules and hydrophilic residues - proton wires.

Chitin microneedles for an easy-to-use tuberculosis skin test.

An easy-to-use tuberculosis skin test is developed with chitin microneedles that deliver purified protein derivative at the correct skin depth and result in a positive test in BCG-immunized guinea pigs.

A biomimetic composite from solution self-assembly of chitin nanofibers in a silk fibroin matrix.

A chitin nanofiber-silk biomimetic nanocomposite with enhanced mechanical properties is self-assembled from solution to yield ultrafine chitin nanofibers embedded in a silk matrix.