Simulations of Glass–Water Interactions

Rimsza, Jessica; Mahadevan, Thiruvilla S.; Deng, Lu; Du, Jincheng

doi:10.1002/9781118939079.ch15

Cited by 3 publications

(2 citation statements)

References 167 publications

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“…Overall, our results show that the observed interfacial reaction mechanisms are very similar between the two potentials. There are very limited available reactive potentials in the literature to study glass–water reactions. , Hence, further developments to include more elements in the currently available potentials, for both ReaxFF and DCRP, and to increase accuracy of the potentials with careful validation to first principles or experimental data are much needed.…”

Section: Discussionmentioning

confidence: 99%

Composition Effect on Interfacial Reactions of Sodium Aluminosilicate Glasses in Aqueous Solution

et al. 2023

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Understanding the underlying reaction mechanisms responsible for aluminosilicate glass dissolution in aqueous environments is crucial for designing glasses for technological applications ranging from architecture windows and touch screens to nuclear waste disposal. This study investigated the glass composition effect on the interfacial reactions of sodium aluminosilicate (NAS) glasses using molecular dynamics (MD) simulations with recently developed reactive potentials. Glass–water interfacial models of six NAS glasses with varying Al2O3/Na2O ratios were investigated for up to 4 nanoseconds (ns) to elucidate the interfacial reaction mechanisms at ambient temperature. The results showed that the coordination defects, such as undercoordinated Si and Al, as well as non-bridging oxygens (NBOs) accumulated at the glass surfaces, play a crucial role in the initial hydration reaction process of the glasses. They promote the formation of silanol (Si–OH) and aluminol (Al–OH) species together with the Na+ ⇔ H+ ion-exchange reactions. The z-density profiles of H2O and H+ ions affirmed the water/H+ propagation into the glass up to 2 nanometers after 4 ns reactions. The penetration depth depends on the composition and shows a nonlinear dependence, suggesting that the subsequent water penetration, particularly into the bulk glass, is supported by the availability of random channels. Aluminol formations, including Al–OH or Al–OH2 near the surface, were found to form mainly through the hydrolysis of Al–O–Al bonds and hydration of Al+–NBO– units. While water molecules are involved in initial interfacial reactions, water penetration into the bulk glass region is primarily achieved by proton transfer. Compared to highly mobile proton transfer involving silanol groups, proton transfer associated with [AlO4]− species is much more limited, particularly in the bulk glass region. These new insights into the role of aluminum in interfacial reactions of the NAS glasses can help to understand the initial dissolution mechanisms and in designing more durable glasses.

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Section: Discussionmentioning

confidence: 99%

Composition Effect on Interfacial Reactions of Sodium Aluminosilicate Glasses in Aqueous Solution

et al. 2023

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“…The increased applications of aluminosilicate (AS) glasses in many fundamental and technological fields with possible exposure to aqueous and humid environments have sparked significant interest in the comprehensive understanding of the AS glass–water interaction, surface corrosion, and their strengthening. − Chemical corrosion of AS glass by water is a serious problem with implications in diverse areas like geochemistry, biomineralization, the management of radioactive nuclear wastes, bioactive glass for the growth and repair of tissues, etc. − As glass corrosion starts on the surface and spreads into the bulk, analyzing the surface chemistry and understanding the hydrolysis mechanism have drawn significant interest in glass research. To this end, many researchers have invested in exploring the hydrolysis and aqueous corrosion of silica and alkali silicate glass surfaces and increasing wear resistance to ensure their long-term durability against chemical attacks. − However, the hydrolysis in multicomponent AS glasses is less studied than in silicates, and details of this mechanism remain obscure despite extensive efforts to understand hydrolysis and corrosion in glasses. − Therefore, it is essential to unravel the atomistic details of the glass–water interface, the behavior of ions, and the degradation mechanism of AS glass surfaces due to hydrolysis to improve them as mechanically strong and durable functional glasses.…”

Section: Introductionmentioning

confidence: 99%

Effects of Na/K–Cl Salts on Hydrolysis of Aluminosilicate Glass Using Ab Initio Molecular Dynamics

Baral,

Li,

Ching

2024

J. Phys. Chem. B

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The structural and chemical modifications on the surface of pure and alkali-doped aluminosilicate (AS) glasses due to hydrolysis are investigated using ab initio molecular dynamics. The effects of water on the glass network are fully elucidated by analyzing the short- and intermediate-range structural orders embedded in the pair distribution function, bond length and angle distribution, coordination number, and interatomic bonding. A novel concept of total bond order is used to quantify and compare the strength of bonds in hydrated and unhydrated glasses. We show that AS glass is hydrolyzed by water diffusion near the surface and by proton (H+) transfers into the bulk, which increases with time. Hence, a dissolved glass–water interface becomes rich in Si–OH and Al–OH. The alkali ions associated with the nonbridging oxygen accelerate the hydrolysis by facilitating water and H+ diffusion. Al is more impacted by hydrolysis than Si, resulting in greater variation in the Al–O bond order than Si–O. Doping of NaCl and KCl enhances the ionization of water and the hydrolysis of ASs with increased salt concentration. The KCl doping ionizes more water molecules and causes more degradation of the glass network than NaCl. Co-doping of Na and K results in a mixed alkali effect due to complex interatomic bonding from different-sized ions. These exceptionally detailed findings in highly complex glasses with varying salt compositions provide new and unprecedented atomistic insights that can help to understand the hydrolysis and dissolution mechanisms of ASs and other silicate glasses.

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Temperature dependence of interfacial reactions of sodium aluminosilicate glasses from reactive molecular dynamics simulations

Kalahe

Mahadevan

Ono

et al. 2023

Applied Surface Science

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Simulations of Glass–Water Interactions

Cited by 3 publications

References 167 publications

Composition Effect on Interfacial Reactions of Sodium Aluminosilicate Glasses in Aqueous Solution

Composition Effect on Interfacial Reactions of Sodium Aluminosilicate Glasses in Aqueous Solution

Effects of Na/K–Cl Salts on Hydrolysis of Aluminosilicate Glass Using Ab Initio Molecular Dynamics

Temperature dependence of interfacial reactions of sodium aluminosilicate glasses from reactive molecular dynamics simulations

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