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The formation of a hydration shell in acetamide aqueous solution has been investigated by means of UV Raman spectroscopy. The experimental results reveal the existence of two distinct regimes of water dynamics. At high acetamide concentration water molecules show a structural and dynamical behavior consistent with the so-called iceberg model. Upon increasing the amount of water we observe the formation of a hydration shell marked by fastening of hydrogen-bond dynamics. Such a behavior may help to shed light on the scientific debate on how water rearranges around the hydrophobic portions of solute molecules (iceberg vs. non-iceberg models).
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http://dx.doi.org/10.1039/c5cp00486a | DOI Listing |
Inorg Chem
September 2025
Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
The solvation structure of an Np ion in an aqueous, noncomplexing and nonoxidizing environment of trifluoromethanesulfonic (triflic) acid was investigated with X-ray absorption spectroscopy (XAS) combined with ab initio molecular dynamics (AIMD) and time-dependent density functional theory (TDDFT) calculations. Np L-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) data were collected for Np in 1, 3, and 7 M triflic acid using a laboratory-scale spectrometer and separately at a synchrotron facility, producing data sets in excellent agreement. TDDFT calculations revealed a weak pre-edge feature not previously reported for Np L-edge XANES.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2025
Soft Matter Sciences and Engineering, CNRS, École supérieure de Physique et de Chimie Industrielles de la Ville de Paris, Université Paris Sciences et Lettres, Sorbonne Université, Paris 75005, France.
The sliding motion of aqueous droplets on hydrophobic surfaces leads to charge separation at the trailing edge, with implications from triple-line friction to hydrovoltaic energy generation. Charges deposited on the solid surface have been attributed to ions or electrons ripped off from the liquid drop. However, the dynamics and exact physicochemical nature of these surface-trapped charges remains poorly explored.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Laboratory of Inorganic Synthesis and Catalysis (LSCI), Institute of Chemical Sciences and Engineering, École Polytechnique Fédéralede Lausanne (EPFL), Lausanne 1015, Switzerland.
The challenge to produce multicarbon (C) products in high current densities in the electrochemical reduction of carbon dioxide (CORR) has motivated intense research. However, the ability of solvated cations to tune and activate water for C production in the CORR has been overlooked. In this study, we report the incorporation of a covalently grown layer of functionalized phenyl groups on the Cu surface that leads to a 7-fold increase in ethylene production (to -530 mA cm) and a 6-fold increase in C products (to -760 mA cm).
View Article and Find Full Text PDFLangmuir
September 2025
School of Materials Science and Engineering, Sun Yat-sen University, Higher Education Megacenter, Guangzhou 510006, P. R. China.
The interface between grafted poly(-isopropylacrylamide) (PNIPAM) and fluid plays an important role in drug delivery, responsive nanomaterials, and separation technologies. However, under external shear, the transport at the interface is regulated by both the thermoresponsive behavior and grafting densities. This study combines equilibrium and nonequilibrium molecular dynamics simulations to investigate the synergistic effects of grafting density, temperature, and shear flow on the structural and dynamic properties of PNIPAM brushes in methanol-water solutions.
View Article and Find Full Text PDFJ Phys Chem B
August 2025
Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.
Sulfonated polystyrene membranes exhibit a nanostructure characterized by tortuous, interconnected hydrophilic pores enclosed by a hydrophobic polymer domain. The characteristic pore size plays a crucial role in determining the salt partition coefficients. To directly relate pore size to salt partitioning, we construct a simplified pore space confined between flat sulfonated polystyrene walls.
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