Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

Monasterio, Manuel; Jansson, Helén; Gaitero, Juan J.; Dolado, Jorge S.; Cerveny, Silvina

doi:10.1063/1.4826638

Cited by 26 publications

(40 citation statements)

References 73 publications

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“…The actual presence of the fragile to strong transition has been however criticised by several authors [174,175,176,177,178,179]. Nevertheless, the activity in this topic may in principle provide indications on universal features of the relaxational behaviour of glass forming materials, included polymers.…”

Section: Experimental Studiesmentioning

confidence: 99%

Dynamics and thermodynamics of polymer glasses

Cangialosi¹

2014

J. Phys.: Condens. Matter

115

112

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The fate of matter when decreasing the temperature at constant pressure is that of passing from gas to liquid and, subsequently, from liquid to crystal. However, a class of materials can exist in an amorphous phase below the melting temperature. On cooling such materials, a glass is formed; that is, a material with the rigidity of a solid but exhibiting no long-range order. The study of the thermodynamics and dynamics of glass-forming systems is the subject of continuous research. Within the wide variety of glass formers, an important sub-class is represented by glass forming polymers. The presence of chain connectivity and, in some cases, conformational disorder are unfavourable factors from the point of view of crystallization. Furthermore, many of them, such as amorphous thermoplastics, thermosets and rubbers, are widely employed in many applications. In this review, the peculiarities of the thermodynamics and dynamics of glass-forming polymers are discussed, with particular emphasis on those topics currently the subject of debate. In particular, the following aspects will be reviewed in the present work: (i) the connection between the pronounced slowing down of glassy dynamics on cooling towards the glass transition temperature (Tg) and the thermodynamics; and, (ii) the fate of the dynamics and thermodynamics below Tg. Both aspects are reviewed in light of the possible presence of a singularity at a finite temperature with diverging relaxation time and zero configurational entropy. In this context, the specificity of glass-forming polymers is emphasized.

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Section: Experimental Studiesmentioning

confidence: 99%

Dynamics and thermodynamics of polymer glasses

Cangialosi¹

2014

J. Phys.: Condens. Matter

115

112

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“…activation energies of various relaxation processes decreased with increasing surface coverage in clay materials [162] and polymer composites [165] but increased in Fe 2 O 3 [156], Ag 2 O [168], silica [170,176], calcium-silicate-hydrate [157,158] and ovalbumine adsorbents [166,171].…”

Section: Dependence Of the Activation Energy On Water Adsorptionmentioning

confidence: 99%

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Kukovecz

Kordás

Kiss

2016

Surface Science Reports

104

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Titanates are salts of polytitanic acid that can be synthesized as nanostructures in a great variety concerning crystallinity, morphology, size, metal content and surface chemistry.Titanate nanotubes (open-ended hollow cylinders measuring up to 200 nm in length and 15 nm in outer diameter) and nanowires (solid, elongated rectangular blocks with length up to 1500 nm and 30-60 nm diameter) are the most widespread representatives of the titanate nanomaterial family. This review covers the properties and applications of these two materials from the surface science point of view. Dielectric, vibrational, electron and X-ray spectroscopic results are comprehensively discussed first, then surface modification methods including covalent functionalization, ion exchange and metal loading are covered. The versatile surface chemistry of onedimensional titanates renders them excellent candidates for heterogeneous catalytic, photocatalytic, photovoltaic and energy storage applications, therefore, these fields are also reviewed.

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“…With the aim of elucidating the processes involved in conduction in cement-based materials and, in particular, of investigating the role of water molecules and the indirect impact of the addition of fillers, we studied graphene nanoplatelets/cement composite by means of dielectric spectroscopy technique at different temperatures. Such a technique, commonly used to study conductivity in ceramic materials [47][48][49][50][51][52] and dielectric and electrical properties of porous systems [53][54][55][56][57][58][59][60] and polymer composite [61][62][63][64][65][66][67][68], is a very suitable tool due to its unique properties. In fact, due to its large frequency range, it is possible to investigate the impedance and dielectric response of the material on different time scale and, therefore, to obtain information on the different processes involved in the ionic and electronic conduction phenomena.…”

Section: Introductionmentioning

confidence: 99%

Elucidation of Conduction Mechanism in Graphene Nanoplatelets (GNPs)/Cement Composite Using Dielectric Spectroscopy

Goracci

Dolado

2020

Materials

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Understanding the mechanisms that govern the conductive properties of multifunctional cement-materials is fundamental for the development of the new applications proposed to enhance the energy efficiency, safety and structural properties of smart buildings and infrastructures. Many fillers have been suggested to increase the electrical conduction in concretes; however, the processes involved are still not entirely known. In the present work, we investigated the effect of graphene nanoplatelets (1 wt% on the electrical properties of cement composites (OPC/GNPs). We found a decrease of the bulk resistivity in the composite associated to the enhancement of the charge transport properties in the sample. Moreover, the study of the dielectric properties suggests that the main contribution to conduction is given by water diffusion through the porous network resulting in ion conductivity. Finally, the results support that the increase of direct current in OPC/GNPs is due to pore refinement induced by graphene nanoplatelets.

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Cause of the fragile-to-strong transition observed in water confined in C-S-H gel

Cited by 26 publications

References 73 publications

Dynamics and thermodynamics of polymer glasses

Dynamics and thermodynamics of polymer glasses

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Elucidation of Conduction Mechanism in Graphene Nanoplatelets (GNPs)/Cement Composite Using Dielectric Spectroscopy

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