We found that the force between glass surfaces measured with an atomic force microscope (AFM) has universal character in the short range, less than approximately 1 nm or about 3-4 water molecules, independent of solution conditions, that is, electrolyte ion size, charge and concentration and pH. Our results suggest that the excess DLVO force, obtained by subtracting the DLVO theory with a charge regulation model from the AFM force data, essentially does not change with the electrolytes Na, Ca, and Al, in the range of concentration from 10(-6) to 10(-2) M and the range of pH from 3.1 to 7.9. Single force curves for a glass-silica system in a 10-4 M aqueous NaCl solution at pH approximately 5.1 show oscillations with a period of about 0.25 nm, roughly the diameter of a water molecule. We postulate that the excess force between glass surfaces arises from a surface-induced solvent effect, from the creation of a hydrogen-bonding network at the surface level, rather than from a solvent-induced surface steric hindrance.
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http://dx.doi.org/10.1021/la703866g | DOI Listing |
Langmuir
January 2025
Department of Chemical Engineering and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, United States.
The chemical reactivity of glass surfaces is often studied with elemental analysis techniques, and although such characterization methods provide insights on compositional changes from exposure to specific chemical conditions, molecule-specific chemical reactions are not determined unambiguously. This study demonstrates the use of reflection-absorption infrared spectroscopy (RAIRS) to detect molecular species on alkali-free boroaluminosilicate and alkali aluminosilicate glasses, using acetic acid vapor as a model reactant to probe reaction sites at the surface with or without pretreatment by aqueous solutions of varied pH. With the assistance of the theoretical calculation of spectral changes based on refractive indices of bulk materials, it was possible to identify the molecular species being removed and produced at the glass surface.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States.
In two-dimensional (2D) chiral metal-halide perovskites (MHPs), chiral organic spacers induce structural chirality and chiroptical properties in the metal-halide sublattice. This structural chirality enables reversible crystalline-glass phase transitions in (-NEA)PbBr, a prototypical chiral 2D MHP where NEA represents 1-(1-naphthyl)ethylammonium. Here, we investigate two distinct spherulite states of (-NEA)PbBr, exhibiting either radial-like or stripe-like banded patterns depending on the annealing conditions of the amorphous film.
View Article and Find Full Text PDFMater Today Bio
February 2025
Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstraße 6, 91058, Erlangen, Germany.
In recent years, metal-organic frameworks (MOFs) have emerged as promising materials for biomedical applications, owing to their superior chemical versatility, unique textural properties and enhanced mechanical properties. However, their fast and uncontrolled degradation, together with the reduced bioactivity have restricted their clinical potential. To overcome these limitations, MOFs can be synergistically combined with other materials, such as bioactive glasses (BGs), known for their bioactivity and therapeutic ion releasing capabilities.
View Article and Find Full Text PDFHeliyon
January 2025
College of Chemical Engineering, Zhejiang University of Technology, China.
Titania (TiO) is one of promising photo catalysts for its high ability to resistant photo corrosion and environmental friendliness, but its photocatalytic activity is too low to be used in industry. To find an approach to solve this problem, graphene oxide (GO), tungsten trioxide (WO) and TiO composite with hollow mesoporous structure was prepared by a two-step spray drying method. The composite was used as raw material to constitute a membrane onto ITO glass to form a membrane photo-anode.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
The Njord Centre, Department of Physics, University of Oslo, Sem Sælands vei 24, NO-0316 Oslo, Norway.
Water participates in countless processes on Earth, and the properties of mineral surfaces can be drastically changed in the presence of water. For example, the fracture toughness of silica glass is reduced by 25% for water-filled cracks than for dry cracks [ , , 9341-9354]. An accurate description of water is therefore essential for modeling the behavior of minerals in aqueous environments and, in particular, for modeling dynamic processes such as fracture, where the mechanical response of water may play an important role.
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