In this Letter we report significant differences in the dielectric behavior of four nonpolymeric and sizable glass-forming molecules with related chemical structures. They belong to the recently constituted class of sizable glass-formers [Jedrzejowska et al. 2020, 101, 010603], for which the pattern of change in dielectric properties with structure has not yet been fully discovered. In the present study we tackle the fundamental problem of the structure-dynamics relationship. It was made possible by judicious choice of investigated systems with the values of dipole moments purposely kept at about the same level, and the only difference is the structure of the terminal substituents applied. The remarkable effect revealed by broadband dielectric spectroscopy is a large difference in the frequency dispersion of the α-relaxation for the systems studied. This interesting finding can be rationalized by the results of X-ray diffraction, clearly indicating the dissimilarities in the local intermolecular structure.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.jpclett.0c03377 | DOI Listing |
J Fluoresc
January 2025
Department of Physics, Jnana Bharathi Campus, Bangalore University, Bengaluru, 560056, India.
This investigation delves into the extraction of polyphenols from the flowers of Tabebuia rosea using a basic maceration approach with acetone, ethanol, and methanol as solvents. The spectroscopic analysis of the dye obtained confirms the existence of functional groups in the polyphenol extract. The study also explores optoelectronic, fluorescence, and photometric characteristics associated with polyphenols.
View Article and Find Full Text PDFIn this work, a specially designed multilayer indium tin oxide (ITO) mesh structure metasurface was proposed as a microwave absorber, achieving both excellent angle-insensitive broadband absorption and high shielding effectiveness (SE). It features gradually changing surface resistance ( ), to expand the absorption bandwidth while maintaining high SE. Also, a folded square ring metasurface was designed to effectively suppress surface wave grating lobes, as well as to reduce the unit size of the metasurface and thus the absorber.
View Article and Find Full Text PDFStretchable microwave absorbers (SMAs) are vital for flexible electronics. Traditional SMAs display unstable tensile properties resulting from inconsistencies between the constrained conductive layer and the flexible dielectric layer. This study introduces an organohydrogel-based stretchable microwave absorber (OSMA) that incorporates an organohydrogel within an island-bridge structure.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2025
Nanoscale Solid-Liquid Interfaces, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Schwarzschildstraße 8, 12489 Berlin, Germany.
MXenes are two-dimensional (2D) materials with versatile applications in optoelectronics, batteries, and catalysis. To unlock their full potential, it is crucial to characterize MXene interfaces and intercalated species in more detail than is currently possible with conventional optical spectroscopies. Here, we combine ultra-broadband ellipsometry and transmission spectroscopy from the mid-infrared (IR) to the deep-ultraviolet (UV) to probe quantitatively the composition, structure, transport, and optical properties of spray-coated TiCT MXene thin films with varying material properties.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemical Engineering, National Institute of Technology, Nara College, Yamatokoriyama, Nara 639-1080, Japan.
This study focuses on two types of phosphonium cation-based ionic liquids (P-ILs) with different alkyl chains: triethylalkylphosphonium (P222R) and tributylalkylphosphonium (P444R) cations. Broadband dielectric spectroscopy showed that the translational motion of the ions accelerated with an increasing number of alkyl chains by coupling with their rotational motion in both P-ILs. Raman spectroscopy revealed that P222R cations, despite dielectric similarities to P444R cations, can form all-trans conformations and cation-rich nanodomains because they have a relatively polar, short alkyl chain moiety with a central P atom and less-polar alkyl chains than those of P444R cations.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!