A5018962146- Synthesis and properties of polymers
- Organic Electronics and Photovoltaics
- Luminescence and Fluorescent Materials
- Organic Light-Emitting Diodes Research
- Conducting polymers and applications
- Polymer Nanocomposites and Properties
- Tribology and Wear Analysis
- Silicone and Siloxane Chemistry
- Epoxy Resin Curing Processes
- Advanced Chemical Sensor Technologies
- Molecular Junctions and Nanostructures
- Thermal and Kinetic Analysis
- Meat and Animal Product Quality
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Chemometric Analyses
- Advanced Fiber Optic Sensors
Tokyo Institute of Technology
1979-2024
This study proposes a molecular design and synthetic route to novel colorless, transparent polyimides that exhibit dual fluorescence/phosphorescence emission at long wavelengths applicable solar energy conversion. Partially alicyclic (Ac-PI-TBs) based on Tröger's base (TB) denoted as Ac-PI-TB-1, Ac-PI-TB-2, Ac-PI-TB-3 were synthesized by in situ TB formation. The resulting Ac-PI-TBs are readily soluble common organic solvents have good mechanical properties with tensile strengths of...
Coefficients of thermal linear and volumetric expansion (CTE, CVE) crystal lattice for 13 fully aromatic crystalline polyimides (PIs) were evaluated from parameters measured variable-temperature (VT) synchrotron X-ray diffraction patterns, the effects chemical structure on CTE CVE are discussed. The smallest (116 ppm K–1) was observed PMDA-PPD with simplest rigid-rod structure, largest anisotropy PMDA-ODA containing an ether linkage extraordinarily negative CTEa (−44 K–1). values CTEs...
The photoluminescence (PL) properties of four types blue fluorescent semi-aliphatic polyimides (PIs) derived from aromatic dianhydrides (ODPA, BPDA, HQDEA, and BPADA) an alicyclic diamine (DCHM) were investigated at temperatures ranging room temperature (RT, 298 K) to 30 K analyse the origins their non-radiative relaxation (NR) processes. These PIs exhibited significant increases in fluorescence (FL) intensity lifetimes when lowering temperature, stabilising below 100 K. containing ether...
Pressure-induced variations in the main chain and aggregation structures of colorless transparent semialiphatic polyimide (PI) films were investigated by optical microscopy, UV-vis absorption, fluorescence spectroscopy up to 8 GPa. Upon application pressures 2 GPa, a gradual volumetric compression was clearly observed definite bathochromic shifts locally excited (LE) absorption bands detected, which attributed interchain free volume enhanced intermolecular interactions. In addition,...
A series of semi-aliphatic polyimide (PI) copolymers (CoPIs) were prepared through the copolymerization two dianhydrides, 1-hydroxy pyromellitic dianhydride (PHDA) and 4,4′-oxydiphthalic anhydride (ODPA), with 4,4′-diaminodicyclohexylmethane, in which PHDA molar ratio was controlled at less than 5% to suppress aggregate formation a solid state. Upon increasing unit, fluorescence color CoPI films continuously changed from pink yellow an orange owing enhanced emission anionic form efficiency...
Abstract Polymers containing 1,4-dihydronicotinamide (P-NAH) alloxan (P-A), and viologen (P-V2+) moieties were synthesized characterized. P-NAH reduced various organic substances such as lipoic acid, alloxan, viologens also immobilized quinone mediated by alloxan. P-A was to the polymer-bearing radical dialuric acid structure without crosslinks one- two-electron reduction, respectively, redox reaction occurring between aqueous (water-immiscible) layers. P-V2+ converted stable reversibly...
The relationship between the photoexcitation dynamics and structures of semi-aliphatic polyimides (3H-PIs) was investigated using ultrafast fluorescent emission spectroscopy at atmospheric increased pressures up to 4 GPa. 3H-PI films exhibited prominent fluorescence with extremely large Stokes shifts (Δν > 10 000 cm–1) through an excited-state intramolecular proton transfer (ESIPT) induced by keto–enol tautomerism isolated dianhydride moiety. incorporation bulky −CH3 −CF3 side groups diamine...
This study discusses the lattice deformation with an increase in pressure or temperature of a rigid-rod aromatic polyimide (PI), poly(p-phenylene pyromellitimide), which was enhanced weight density lattice. unique behavior is caused by suppression deformation, means "misfit strain", induced mismatch interchain distances between crystalline and noncrystalline domains. For compression under hydrostatic pressure, suppressed decrease crystallinity and/or number PI chains penetrating interfaces...
Excited state intramolecular proton transfer (ESIPT) is one of the distinctive photophysical processes fluorescent compounds and polymers, which induces enhanced fluorescence with a very large Stokes shift. In this work, 6FDA/DCHM/3HPA polyimides (PIs) having bulky –CF3 groups were synthesized, in 3HPA an end-group exhibits ESIPT green emission when irradiated by UV light at 365 nm. Introduction side chains can improve properties via suppression aggregation induced quenching as well...
Pressure-induced variations in refractive indices and acoustic velocities of a spin-coated aromatic polyimide (PI) film, poly(4,4'-oxidiphenylene pyromellitimide), were analyzed between atmospheric pressure (0.1 MPa) 2 GPa by Brillouin scattering measurements with the symmetric platelet back geometries for film surface cross-sectional surface. At high pressures, anisotropies velocity clearly observed in-plane out-of-plane directions. Additionally, average index PI was estimated to increase...
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to Precise Analysis of Thermal Volume Expansion Crystal Lattice for Fully Aromatic Crystalline Polyimides by X-ray Diffraction Method: Relationship between Molecular Structure and Linear/Volumetric ExpansionRyohei Ishige, Toshiaki Masuda, Yukiko Kozaki, Eisuke Fujiwara, Tomohiro Okada, Shinji Ando*Cite this: Macromolecules 2017, 50, 6, 2599–2600Publication Date (Web):March 16,...
To develop a novel spectroscopic method for quantitative evaluation of detergency, attenuated total reflection (ATR)-FT/IR spectroscopy was applied analysis oil- and protein-based soil components adhering to cotton fibres without precedent extraction procedure. In addition, influence washing time mechanical action on the detergency soap (sodium salt fatty acid) soils clothing examined by using this method. particular, contents can be separately estimated relative intensities their...
Pressure-induced variations in the crystalline structures of polyimides (PIs) that have flexible ether or thioether linkages along main chain were analyzed by synchrotron wide-angle X-ray diffraction at high pressures up to 2.0 GPa. The lattices poly(4,4-oxidiphenylene pyromellitimide) (PMDA/ODA) and poly(4,4'-diamino-diphenyl sulfide (PMDA/SDA) PIs one linkage their repeating unit showed negative linear compressibility main-chain direction (c-axis), with a large anisotropy compressibilities...