Structural origin of the anomalous density maximum in silica and alkali silicate glasses

Shih, Yueh-Ting; Sundararaman, Siddharth; Huang, Liping

doi:10.1111/jace.16850

Cited by 9 publications

(16 citation statements)

References 49 publications

(61 reference statements)

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“…It can be also seen that the ring distributions of the 0‐8 GPa samples (the T 2 values of 0 and 4 GPa samples are around 3000 K and the T 2 of the 8 GPa is around 2700 K, see Table 1) from 3600 to 3000 K tend to become more centralized around 6~7 rings. In the study by Shih et al, 25 the density maximum, viz., the local minimum of L at T 2 , has been attributed to the tendency to form 6‐member rings. Based on these, we propose that the local density maximum (the reason for the existence of T 2 ) results from (a) the increase of CN Si‐O and CN Si‐Si , which tend to increase the glass density from T 1 to T 2 ; (b) the tendency to break rings whose sizes are close to 6 or 7 when the silica glass is further heated above T 2 ; and (c) the increase of bond length of Si–O or Si–Si at T > T 2 , which further helps increase the volume.…”

Section: Resultsmentioning

confidence: 99%

Understanding thermal expansion of pressurized silica glass using topological pruning of ring structures

Yang

Tokunaga²,

Hayashi³

et al. 2020

J. Am. Ceram. Soc.

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We investigate the structural origin of the large thermal expansion coefficient of hotcompressed silica glass upon heating to a threshold temperature using molecular dynamics (MD) simulations. While the simulated thermal expansion at low temperature correlates well with the elongation of the average interatomic separation distance of the Si-O or Si-Si pair, the excess thermal expansion due to hot compression mainly results from change in medium range order, including a decrease in the population of large rings upon heating, without significant modification of the small ring population and without changing the short range ordering, such as the Si-O coordination number. The reduction in the characteristic ring size can be connected to the high thermal expansion through the topological pruning mechanism. Such large thermal expansion is suppressed when the silica glasses are held at their respective quench pressures. The suppression of this excess thermal expansion is consistent with the pressure stabilization of the large ring structures.

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Section: Resultsmentioning

confidence: 99%

Understanding thermal expansion of pressurized silica glass using topological pruning of ring structures

Yang

Tokunaga²,

Hayashi³

et al. 2020

J. Am. Ceram. Soc.

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“…Therefore, only three definitions are eligible for ring size analyses in glass structures. Among RINGS' users, the primitive definition has been almost exclusively adopted (19)(20)(21), with the exception of ( 22) wherein the Guttman's definition was used. In most papers focusing on rings, no reasons are provided as to why a specific definition is adopted.…”

Section: Contribution Of Individual Ring Sizes To the Fsdpmentioning

confidence: 99%

Experimental method to quantify the ring size distribution in silicate glasses and simulation validation thereof

et al. 2021

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Silicate glasses have no long-range order and exhibit a short-range order that is often fairly similar to that of their crystalline counterparts. Hence, the out-of-equilibrium nature of glasses is largely encoded in their medium-range order. However, the ring size distribution—the key feature of silicate glasses’ medium-range structure—remains invisible to conventional experiments and, hence, is largely unknown. Here, by combining neutron diffraction experiments and force-enhanced atomic refinement simulations for two archetypical silicate glasses, we show that rings of different sizes exhibit a distinct contribution to the first sharp diffraction peak in the structure factor. On the basis of these results, we demonstrate that the ring size distribution of silicate glasses can be determined solely from neutron diffraction patterns, by analyzing the shape of the first sharp diffraction peak. This method makes it possible to uncover the nature of silicate glasses’ medium-range order.

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“…G1 is formed as a result of the co‐assembly between TEOS and F127 as no hydrogel was obtained in the absence of TEOS under the same conditions (Table S1, entry 13). Although it is difficult to quantify the binding energy between the monomer and the template, the measured yield strain (Figure S6) of G1 reflects the energy required to extensively break the non‐covalent interactions between TEOS and F127 to facilitate the solid‐to‐liquid transition.…”

Section: Figurementioning

confidence: 99%

Hierarchical Co‐Assembly Enhanced Direct Ink Writing

Zhang

et al. 2018

Angew Chem Int Ed

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Integrating intelligent molecular systems into 3D printing materials and transforming their molecular functions to the macroscale with controlled superstructures will unleash great potential for the development of smart materials. Compared to macromolecular 3D printing materials, self-assembled small-molecule-based 3D printing materials are very rare owing to the difficulties of facilitating 3D printability as well as preserving their molecular functions macroscopically. Herein, we report a general approach for the integration of functional small molecules into 3D printing materials for direct ink writing through the introduction of a supramolecular template. A variety of inorganic and organic small-molecule-based inks were 3D-printed, and their superstructures were refined by post-printing hierarchical co-assembly. Through spatial and temporal control of individual molecular events from the nano- to the macroscale, fine-tuned macroscale features were successfully installed in the monoliths.

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Structural origin of the anomalous density maximum in silica and alkali silicate glasses

Cited by 9 publications

References 49 publications

Understanding thermal expansion of pressurized silica glass using topological pruning of ring structures

Understanding thermal expansion of pressurized silica glass using topological pruning of ring structures

Experimental method to quantify the ring size distribution in silicate glasses and simulation validation thereof

Hierarchical Co‐Assembly Enhanced Direct Ink Writing

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