Limited surface mobility inhibits stable glass formation for 2-ethyl-1-hexanol

Tylinski, M.; Beasley, M. S.; Chua, Yeong Zen; Schick, Christoph; Ediger, M. D.

doi:10.1063/1.4977787

Cited by 21 publications

(13 citation statements)

References 69 publications

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“…As an example, the surface diffusion coefficient of o-terphenyl (OTP), a non HB-molecule, and sorbitol (HB molecule), two molecules with similar sizes, differ by 10 5 at T g [132]. In the same reasoning line, it was shown that molecules forming extensive intermolecular HB, such as polyalcohols, produced glasses of lower kinetic stability compared to non-hydrogen-bonding molecules at the same deposition rate [88,91,93,132].…”

Section: Is Surface Diffusion Responsible For Ultrastable Glass Forma...mentioning

confidence: 93%

Ultrastable glasses: new perspectives for an old problem

et al. 2022

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Ultrastable glasses (mostly prepared from the vapor phase under optimized deposition conditions) represent a unique class of materials with low enthalpies and high kinetic stabilities. These highly stable and dense glasses show unique physicochemical properties, such as high thermal stability, improved mechanical properties or anomalous transitions into the supercooled liquid, offering unprecedented opportunities to understand many aspects of the glassy state. Their improved properties with respect to liquid-cooled glasses also open new prospects to their use in applications where liquid-cooled glasses failed or where not considered as usable materials. In this review article we summarize the state of the art of vapor-deposited (and other) ultrastable glasses with a focus on the mechanism of equilibration, the transformation to the liquid state and the low temperature properties. The review contains information on organic, metallic, polymeric and chalcogenide glasses and an updated list with relevant properties of all materials known today to form a stable glass.

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Section: Is Surface Diffusion Responsible For Ultrastable Glass Forma...mentioning

confidence: 93%

Ultrastable glasses: new perspectives for an old problem

et al. 2022

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“…16 In vapor deposition, molecules forming extensive intermolecular HBs (e.g., polyalcohols) have been observed to produce glasses of lower kinetic stability than non-hydrogen-bonding molecules at the same deposition rate 17 and require slower deposition in order to attain the same stability. 18 Qualitative explanations have been proposed for the molecular dependence of surface mobility. 15,16 The size effect is attributed to a steep gradient of mobility beneath the free surface and the deeper penetration of a larger molecule into that gradient.…”

Section: Articlementioning

confidence: 99%

Effect of molecular size and hydrogen bonding on three surface-facilitated processes in molecular glasses: Surface diffusion, surface crystal growth, and formation of stable glasses by vapor deposition

Chen

Tylinski

et al. 2019

The Journal of Chemical Physics

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Recent work has shown that diffusion and crystal growth can be much faster on the surface of molecular glasses than in the interior and that the enhancement effect varies with molecular size and intermolecular hydrogen bonds (HBs). In a related phenomenon, some molecules form highly stable glasses when vapor-deposited, while others (notably those forming extensive HBs) do not. Here we examine all available data on these phenomena for quantitative structure-property relations. For the systems that form no HBs, the surface diffusion coefficient D s decreases with increasing molecular size d (d = Ω 1/3 , where Ω is the molecular volume); when evaluated at the glass transition temperature T g , D s decreases ∼5 orders of magnitude for 1 nm of increase in d. Assuming that center-of-mass diffusion is limited by the deepest part of the molecule in the surface-mobility gradient, these data indicate a mobility gradient in reasonable agreement with the Elastically Collective Nonlinear Langevin Equation theory prediction for polystyrene as disjointed Kuhn monomers. For systems of similar d, the D s value decreases with the extent of intermolecular HB, x (HB), defined as the fraction of vaporization enthalpy due to HB. For both groups together (hydrogenbonded and otherwise), the D s data collapse when plotted against d/[1 − x(HB)]; this argues that the HB effect on D s can be described as a narrowing of the surface mobility layer by a factor [1 − x(HB)] relative to the van der Waals systems. Essentially the same picture holds for the surface crystal growth rate u s. The kinetic stability of a vapor-deposited glass decreases with x(HB) but is not better organized by the combined variable d/[1 − x(HB)]. These results indicate that surface crystal growth depends strongly on surface diffusion, whereas the formation of stable glasses by vapor deposition may depend on other factors.

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“…Elastomer materials are widely utilized in the fields of electronics, aerospace and military because of their low density, remarkable adaptability, and easy-processing properties, and so forth. − However, most of the elastomer materials are strongly influenced by their servicing environment. − For example, at the temperature below −125 °C, they experience brittleness and cracking, leading to strong degradations of the elastomeric materials performance.…”

Section: Introductionmentioning

confidence: 99%

Exploiting Synergistic Experimental and Computational Approaches to Design and Fabricate High-Performance Elastomer

Hou

Xinyi

et al. 2020

Macromolecules

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Silicone elastomers (SRs) are of great scientific and technological importance due to their resistance to low temperatures. However, the glass transition temperature (T g) of existing SRs is not low enough to satisfy its utilization in the extremely low-temperature environment. Meanwhile, crystallization often occurs at the low-temperature, making it difficult for SRs to maintain their original properties in the extremely low-temperature environment. Here, by combining molecular dynamics (MD) simulation and experiment, a novel low-temperature resistance and crystalline-free SR (Epoxidized-Methyl-Ethyl-Vinyl Silicone Elastomer, also referred to E-MEVQ) is fabricated by random copolymerization of three different siloxane repeat units (dimethyl-siloxane, diethyl-siloxane and methyl-epoxy-siloxane). We showed that the T g of E-MEVQ computed from MD simulations using three different methods (specific volume, nonbond potential energy and conformational transition versus temperature) agrees well with that of the as-synthesized E-MEVQ determined by Differential Scanning Calorimetry. The T g is approximately −130 °C, much lower than that of Polydimethylsiloxane (PDMS), and the E-MEVQ is in the amorphous state without any crystallization. This novel silicone elastomer is expected to be widely applied in the field of smart devices, sensors, and medical equipment under extreme situations. Our work also provides a promising framework for designing and fabricating high-performance elastomeric polymer materials via simulation and experiment.

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Limited surface mobility inhibits stable glass formation for 2-ethyl-1-hexanol

Cited by 21 publications

References 69 publications

Ultrastable glasses: new perspectives for an old problem

Ultrastable glasses: new perspectives for an old problem

Effect of molecular size and hydrogen bonding on three surface-facilitated processes in molecular glasses: Surface diffusion, surface crystal growth, and formation of stable glasses by vapor deposition

Exploiting Synergistic Experimental and Computational Approaches to Design and Fabricate High-Performance Elastomer

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