Materials design and characterization of injectable and degradable oxidized alginate PANI:PSS hydrogels for photothermal therapy.

Photothermal therapy has gained great attention as an alternative candidate for radiation therapy or chemotherapy for cancers. However, photothermal agents for photothermal therapy are generally in the form of nanoparticles that are too small to remain in the target tissue, and therefore, the agents are rather quickly removed from the targeted site. Furthermore, conventional photothermal agents are generally expensive or complicated to synthesize.

Enhanced Energy Storage Performance and Efficiency in Bi(NaK)TiO-BiSrTiO Relaxor Ferroelectric Ceramics via Domain Engineering.

Dielectric materials are highly desired for pulsed power capacitors due to their ultra-fast charge-discharge rate and excellent fatigue behavior. Nevertheless, the low energy storage density caused by the low breakdown strength has been the main challenge for practical applications. Herein, we report the electric energy storage properties of (1 - ) Bi(NaK)TiO-BiSrTiO (BNKT-BST; = 0.

Preparation and Characterization of Poly(Acrylic Acid)-Based Self-Healing Hydrogel for 3D Shape Fabrication via Extrusion-Based 3D Printing.

The three-dimensional (3D) printing of hydrogel is an issue of interest in various applications to build optimized 3D structured devices beyond 2D-shaped conventional structures such as film or mesh. The materials design for the hydrogel, as well as the resulting rheological properties, largely affect its applicability in extrusion-based 3D printing. Here, we prepared a new poly(acrylic acid)-based self-healing hydrogel by controlling the hydrogel design factors based on a defined material design window in terms of rheological properties for application in extrusion-based 3D printing.

Synthesis of Yttria-Stabilized Zirconia Nanospheres from Zirconium-Based Metal-Organic Frameworks and the Dielectric Properties.

Yttria-stabilized zirconia (YSZ) nanospheres were synthesized by calcination at 900 °C after the adsorption of Y ions into the pores of a zirconium-based metal-organic framework (MOF). The synthesized 3YSZ (zirconia doped with 3 mol% YO), 8YSZ (8 mol% YO), and 30YSZ (30 mol% YO) nanospheres were found to exhibit uniform sizes and shapes. Complex permittivity and complex permeability were carried out in K-band (i.

3D Antidrying Antifreezing Artificial Skin Device with Self-Healing and Touch Sensing Capability.

Hydrogels are attractive, active materials for various e-skin devices based on their unique functionalities such as flexibility and biocompatibility. Still, e-skin devices are generally limited to simple structures, and the realization of optimal-shaped 3D e-skin devices for target applications is an intriguing issue of interest. Furthermore, hydrogels intrinsically suffer from drying and freezing issues in operational capability for practical applications.

Three-Dimensional Self-Healable Touch Sensing Artificial Skin Device.

Human skin is a unique functional material that perfectly covers body parts having various complicated shapes, spontaneously heals mechanical damage, and senses a touch. E-skin devices have been actively researched, focusing on the sensing functionality of skin. However, most e-skin devices still have limitations in their shapes, and it is a challenging issue of interest to realize multiple functionalities in one device as human skin does.

Room-Temperature-Phosphorescence-Based Dissolved Oxygen Detection by Core-Shell Polymer Nanoparticles Containing Metal-Free Organic Phosphors.

The highly sensitive optical detection of oxygen including dissolved oxygen (DO) is of great interest in various applications. We devised a novel room-temperature-phosphorescence (RTP)-based oxygen detection platform by constructing core-shell nanoparticles with water-soluble polymethyloxazoline shells and oxygen-permeable polystyrene cores crosslinked with metal-free purely organic phosphors. The resulting nanoparticles show a very high sensitivity for DO with a limit of detection (LOD) of 60 nm and can be readily used for oxygen quantification in aqueous environments as well as the gaseous phase.

A Novel Mechanism for Chemical Sensing Based on Solvent-Fluorophore-Substrate Interaction: Highly Selective Alcohol and Water Sensor with Large Fluorescence Signal Contrast.

Differentiation of solvents having similar physicochemical properties, such as ethanol and methanol, is an important issue of interest. However, without performing chemical analyses, discrimination between methanol and ethanol is highly challenging due to their similarity in chemical structure as well as properties. Here, we present a novel type of alcohol and water sensor based on the subtle differences in interaction among solvent analytes, fluorescent organic molecules, and a mesoporous silica gel substrate.

Shear-Triggered Crystallization and Light Emission of a Thermally Stable Organic Supercooled Liquid.

Thermodynamics drive crystalline organic molecules to be crystallized at temperatures below their melting point. Even though molecules can form supercooled liquids by rapid cooling, crystalline organic materials readily undergo a phase transformation to an energetically favorable crystalline phase upon subsequent heat treatment. Opposite to this general observation, here, we report molecular design of thermally stable supercooled liquid of diketopyrrolopyrrole (DPP) derivatives and their intriguing shear-triggered crystallization with dramatic optical property changes.

Multi-luminescent switching of metal-free organic phosphors for luminometric detection of organic solvents.

Metal-free organic phosphors can be an attractive smart optical sensing materials since, in such compounds, intersystem crossing (ISC) and the phosphorescence process are placed in subtle competition with fluorescence, internal conversion (IC), and non-radiative decay pathways. Here, we report a unique environment-dependent multi-luminescence switching behavior of metal-free organic phosphorescent materials. Through combined photophysical measurements and computational electronic structure analysis, we systematically investigated how physicochemical properties of organic solvents affect the photophysical pathways of the metal-free organic phosphors.

Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials.

Metal-free organic phosphorescent materials are attractive alternatives to the predominantly used organometallic phosphors but are generally dimmer and are relatively rare, as, without heavy-metal atoms, spin-orbit coupling is less efficient and phosphorescence usually cannot compete with radiationless relaxation processes. Here we present a general design rule and a method to effectively reduce radiationless transitions and hence greatly enhance phosphorescence efficiency of metal-free organic materials in a variety of amorphous polymer matrices, based on the restriction of molecular motions in the proximity of embedded phosphors. Covalent cross-linking between phosphors and polymer matrices via Diels-Alder click chemistry is devised as a method.

Designing interchain and intrachain properties of conjugated polymers for latent optical information encoding.

Building molecular-design insights for controlling both the intrachain and the interchain properties of conjugated polymers (CPs) is essential to determine their characteristics and to optimize their performance in applications. However, most CP designs have focused on the conjugated main chain to control the intrachain properties, while the design of side chains is usually used to render CPs soluble, even though the side chains critically affect the interchain packing. Here, we present a straightforward and effective design strategy for modifying the optical and electrochemical properties of diketopyrrolopyrrole-based CPs by controlling both the intrachain and interchain properties in a single system.

High-Performing Thin-Film Transistors in Large Spherulites of Conjugated Polymer Formed by Epitaxial Growth on Removable Organic Crystalline Templates.

Diketopyrrolopyrrole (DPP)-based conjugated polymer PDTDPPQT was synthesized and was used to perform epitaxial polymer crystal growth on removable 1,3,5-trichlorobenzene crystallite templates. A thin-film transistor (TFT) was successfully fabricated in well-grown large spherulites of PDTDPPQT. The charge carrier mobility along the radial direction of the spherulites was measured to be 5.

Elongation of fibers from highly viscous dextran solutions enables fabrication of rapidly dissolving drug carrying fabrics.

A simple method is presented for forming thread-like fibers from highly viscous dextran solutions. Based on the cohesive and adhesive forces between a dextran solution and the substrate to which it is applied, multiple fibers of approximately 10 μm in diameter can be elongated simultaneously. These fibers can be woven into multiple layers to produce fabrics of varying fiber orientations and mechanical properties.

Molecular design principle of all-organic dyes for dye-sensitized solar cells.

All-organic dyes have shown promising potential as an effective sensitizer in dye-sensitized solar cells (DSSCs). The design concept of all-organic dyes to improve light-to-electric-energy conversion is discussed based on the absorption, electron injection, dye regeneration, and recombination. How the electron-donor-acceptor-type framework can provide better light harvesting through bandgap-tuning and why proper arrangement of acceptor/anchoring groups within a conjugated dye frame is important in suppressing improper charge recombination in DSSCs are discussed.

A white-light-emitting molecule: frustrated energy transfer between constituent emitting centers.

White-light-emitting single molecules are promising materials for use in a new generation of displays and light sources because they offer the possibility of simple fabrication with perfect color reproducibility and stability. To realize white-light emission at the molecular scale, thereby eliminating the detrimental concentration- or environment-dependent energy transfer problem in conventional fluorescent or phosphorescent systems, energy transfer between a larger band-gap donor and a smaller band-gap acceptor must be fundamentally blocked. Here, we present the first example of a concentration-independent ultimate white-light-emitting molecule based on excited-state intramolecular proton transfer materials.