Melting of ice in porous solids

Rennie, George; Clifford, John N.

doi:10.1039/f19777300680

Cited by 113 publications

(102 citation statements)

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“…Earlier studies by DSC pointed out that melting point depression of bulk materials in a nanoconfined environment is common for both liquid and solid guest phases, including water (33)(34)(35), benzene (36,37), cyclohexane (36), heptanes (36), o-terphenyl (38), benzyl alcohol (38), ibuprofen (36,39), and glycine (40). Similar behavior was also found in a system containing metal clusters; confined iridium clusters in controlled-pore glass showed lower melting point as pore size decreased (41).…”

Section: Discussionsupporting

confidence: 51%

“…As early as the 1960s, Litvan et al reported that confined water molecules bond strongly onto the wall of silica pores and show nonbulk behavior (46). In later reports, Rennie et al suggested that in addition to the tightly bound water near the pore walls, the water at the center of the pores showed behavior similar to that of bulk water, with greater mobility (33). Additionally, recent work by Erko et al revealed that upon confinement, water showed a two-step density profile with two layers of water near the pore wall having higher density than the core water (47).…”

Section: Discussionmentioning

confidence: 97%

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Guest–host interactions of a rigid organic molecule in porous silica frameworks

Hwang

Zones

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Molecular-level interactions at organic-inorganic interfaces play crucial roles in many fields including catalysis, drug delivery, and geological mineral precipitation in the presence of organic matter. To seek insights into organic-inorganic interactions in porous framework materials, we investigated the phase evolution and energetics of confinement of a rigid organic guest, N,N,N-trimethyl-1-adamantammonium iodide (TMAAI), in inorganic porous silica frameworks as a function of pore size (0.8 nm to 20.0 nm). We used hydrofluoric acid solution calorimetry to obtain the enthalpies of interaction between silica framework materials and TMAAI, and the values range from −56 to −177 kJ per mole of TMAAI. The phase evolution as a function of pore size was investigated by X-ray diffraction, IR, thermogravimetric differential scanning calorimetry, and solid-state NMR. The results suggest the existence of three types of inclusion depending on the pore size of the framework: single-molecule confinement in a small pore, multiple-molecule confinement/adsorption of an amorphous and possibly mobile assemblage of molecules near the pore walls, and nanocrystal confinement in the pore interior. These changes in structure probably represent equilibrium and minimize the free energy of the system for each pore size, as indicated by trends in the enthalpy of interaction and differential scanning calorimetry profiles, as well as the reversible changes in structure and mobility seen by variable temperature NMR.mesoporous silica | thermodynamics | porous materials K nowing both the structure and molecular mobility of guest matter in nanosized pores and channels, which often differ from those in the bulk unconfined material or solution, is essential for fundamental understanding of processes in both science and technology, with applications including natural processes such as biomineralization (1-3) and membrane transport (4, 5), engineering processes such as oil recovery (6-8), CO 2 sequestration (9-11), catalysis (12-14), and biomedical processes including diagnostics and drug delivery (15-17). Most of the pioneering research has used soft matter as guests, including gas and liquid phases, low-melting point organic solids, and longchain polymers (18)(19)(20).In our earlier studies, various calorimetric methods have been designed to investigate guest-host interactions. Piccione et al.(21) developed a novel system for hydrofluoric acid (HF) solution calorimetry to study the interactions of four different silica zeolite frameworks with several quaternary ammonium structure-directing agents (SDAs). The enthalpies of interaction were measured to be −32.0 to −181.0 kJ per mole of SDA. Slightly stronger interactions were found by Trofymluk et al. (22) for mesoporous silica phases containing long-chain molecules. Recently, Wu et al. (23) measured the enthalpy of interaction of various small molecules with mesoprous silicas using immersion calorimetry. The hydration enthalpies of a series of cation exchanged aluminosilicate or gallosilicate ze...

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Section: Discussionsupporting

confidence: 51%

Section: Discussionmentioning

confidence: 97%

Guest–host interactions of a rigid organic molecule in porous silica frameworks

Hwang

Zones

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…As the T 1 of ice is about 2 s (25) or more, the observed minimum T 1 of 0.1 s indicates that the surface water remains unfrozen even when water in the bulk region freezes and that the apparent minimum T 1 is attributed to the T 1s of the unfrozen surface water. The presence of an unfrozen interfacial layer of water separating ice from surfaces has been detected in many water-surface systems (10,13,31), and unfrozen water has been considered to play a major role in the freezing-thawing mechanism of the system (32). In Fig.…”

Section: Nmr Linewidthmentioning

confidence: 99%

Studies of Water Adsorbed in Porous Vycor Glass

Hirama¹,

Takahashi²,

Hino³

et al. 1996

Journal of Colloid and Interface Science

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“…This technique, called thermoporosimetry, was initially developed for measuring pore size distribution in other materials (28)(29)(30) but has been � � Tools for the Characterization of Biomass at the Nanometer Scale 65 successfully applied to pulp fibers (31,32). The relations between the specific melting enthalpy and pore size are described by the Gibbs-Thompson equation:…”

Section: Porosimetry By Differential Scanning Calorimetrymentioning

confidence: 99%