Structure, Luminescence, and Magnetic Properties of Crystalline Manganese Tungstate Doped with Rare Earth Ion

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.

Preparation of Cellulose-Based Fluorescent Materials as Coating Pigment by Use of DMSO/DBU/CO2 System

A series of cellulose-based fluorescent materials are prepared under relative mild conditions by use of the DMSO/DBU/CO2 system to utilize as coating pigments. Through the observation under 365nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~39% and ~66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose.

Preparation of Cellulose-based fluorescent materials as coating pigment by use of reversible DMSO/DBU/CO2 system

A series of cellulose-based fluorescent materials are prepared under relative mild conditions by use of the reversible DMSO/DBU/CO2 system to utilize as coating pigments. Through the observation under 365nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~ 39% and ~ 66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose.

Preparation of Cellulose-based fluorescent materials as coating pigment by use of reversible DMSO/DBU/CO2 system

A series of cellulose-based fluorescent materials are prepared under relative mild condition by use of the particular reversible DMSO/DBU/CO2 system to utilize as coating pigments. Through the observation under 365nm UV light, the cellulose-based fluorescent materials exhibit good fluorescence response and bright color. Furthermore, due to the limitation of the molecular skeleton of cellulose, the intrinsic aggregation caused quenching phenomenon commonly existed in conventional organic fluorescent pigments can be effectively inhibited, which is very helpful to retain good fluorescence response in epoxy-based coating material and its coating films. Moreover, the addition of cellulose-based fluorescent materials also increases the mechanical properties of the coating film. The increase of tensile strength and tensile modulus respectively reaches ~ 39% and ~ 66%. Solvent resistance and thermal property of the coating films generally remain unchanged. The fabrication of cellulose-based fluorescent materials in DMSO/DBU/CO2 system provides a feasible way to develop the functional application of cellulose.

Systematic Study on Sensing Capability of Gold(I) Pyrazolate Complex for Vapochromic Chemosensors of Ethanol Vapors

Modified gold complexes as dinuclear adducts with silver bridge ions, clusters with other metal ions, and bimetallic sandwiches have shown better sensing capabilities for vapochromic chemosensing of organic vapors than its unmodified structure. Herein, a simple gold(I) complex, synthesized from 4-(3,5-dimethoxybenzyl)-3,5-dimethyl pyrazole ligand, have been shown to have higher sensing capability toward ethanol (EtOH) vapors. Such sensing capability can be possibly achieved when EtOH vapors have enough time to diffuse to the main sensing sites of the sensor. Thus, 80 to 160 µL (with 20 µL increment) of EtOH vapors were exposed to the synthesized gold(I) pyrazolate complex at varied distances of 2.75, 11 and 22 cm for 15 minutes. The complex displayed its sensing capability by quenching at its emission intensity of 600 nm up to 80%, which suggests the possible interaction of the EtOH vapors with the inner sensing site originated from the Au(I)–Au(I) interaction of the complex where it is possible to breakdown the light-emitting capability. Prior to this interaction, there was only a slight blue-shifting of 9 nm away from its emission intensity by the binding of EtOH vapors to the methoxy of benzene ring hence only demonstrating weak sensing capability. These results indicated that sensing capability as shown by the quenching phenomenon at the emission intensity of gold(I) complex is dependent on diffusion time of EtOH vapors.