Sintering process of amorphous SiO2 nanoparticles investigated by AFM, IR and Raman techniques

Buscarino, Gianpiero; Ardizzone, Vincenzo; Vaccaro, G.; Gelardi, F. M.

doi:10.1016/j.jnoncrysol.2010.11.114

Cited by 19 publications

(13 citation statements)

References 21 publications

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“…Raman spectrum in Fig. 1(b) [16,17].In addition, the weak Raman peak emerged at around 518 cm -1 could be attributed to the residual silicon crystals existing in the silica fume [18].…”

Section: Original Sf Slurrymentioning

confidence: 94%

Tracing the status of silica fume in cementitious materials with Raman microscope

Yue

Wang

Bai

2018

Construction and Building Materials

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Silica fume (SF) is an essential material for formulating high performance concrete (HPC). However, its small particle size could cause safety-hazards. Although replacing SF powder with slurry can somehow avoid the potential bio-toxicity, its long-term stability within cementitious materials is unknown. In this study, Raman microscope which combines Raman spectroscopy with light-optical microscope was successfully applied to characterise the composition and morphology of SF in original slurry and hydrated SF-Portland cement (PC) pastes. The unhydrated SF-agglomerates were clearly detected in the original SF slurry and the 22-hour and 6-month hydrated SF-PC pastes.

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“…Raman spectrum in Fig. 1(b) [16,17].In addition, the weak Raman peak emerged at around 518 cm -1 could be attributed to the residual silicon crystals existing in the silica fume [18].…”

Section: Original Sf Slurrymentioning

confidence: 94%

Tracing the status of silica fume in cementitious materials with Raman microscope

Yue

Wang

Bai

2018

Construction and Building Materials

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“…40,58 The surface silica network of such a highly hydrated solid surface gives rise to peaks that differ from peaks of bulk silica. 39,[59][60][61] This hypothesis is supported by an increase in the intensity of the peak at 640 cm À1 , i.e. the Si-O-Si symmetric stretch.…”

Section: Relative Humidity Dependent Adsorption Of Water Onto Silica ...mentioning

confidence: 99%

Optical trapping and Raman spectroscopy of solid particles

Rkiouak

Tang

Camp

et al. 2014

Phys. Chem. Chem. Phys.

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The heterogeneous interactions of gas molecules on solid particles are crucial in many areas of science, engineering and technology. Such interactions play a critical role in atmospheric chemistry and in heterogeneous catalysis, a key technology in the energy and chemical industries. Investigating heterogeneous interactions upon single levitated particles can provide significant insight into these important processes. Various methodologies exist for levitating micron sized particles including: optical, electrical and acoustic techniques. Prior to this study, the optical levitation of solid micron scale particles has proved difficult to achieve over timescales relevant to the above applications. In this work, a new vertically configured counter propagating dual beam optical trap was optimized to levitate a range of solid particles in air. Silica (SiO2), α-alumina (Al2O3), titania (TiO2) and polystyrene were stably trapped with a high trapping efficiency (Q = 0.42). The longest stable trapping experiment was conducted continuously for 24 hours, and there are no obvious constraints on trapping time beyond this period. Therefore, the methodology described in this paper should be of major benefit to various research communities. The strength of the new technique is demonstrated by the simultaneous levitation and spectroscopic interrogation of silica particles by Raman spectroscopy. In particular, the adsorption of water upon silica was investigated under controlled relative humidity environments. Furthermore, the collision and coagulation behaviour of silica particles with microdroplets of sulphuric acid was followed using both optical imaging and Raman spectroscopy.

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“…2. These aerosil groups and their surface appearances were also studied in aerosil tablet forms [15,16]. When we compare these results, the similarities are spectacular and this shows that starting with the ρ s =0.347 sample, the volume and therefore the surface is dominantly composed of aerosils.…”

Section: Resultsmentioning

confidence: 93%

Roughness as a measurement of random disorder

Ramazanoglu,

Salci

2017

Preprint

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We have studied the quenched random disorder (QRD) effects created by aerosil dispersion in octylcyanobiphenyl (8CB) liquid crystal (LC) using Atomic Force Microscopy (AFM) technique. Gelation process in the 8CB+aerosil gels yields a QRD network which also changes the surface topography. By increasing the aerosil concentration, the original smooth pattern of LC sample surfaces is suppressed by creating a fractal aerosil surface effect; these surfaces become more porous, rougher with more and bigger crevices. The dispersed aerosil also serves as pinning centers for the liquid crystal molecules. It has been observed that via the diffusion-limited-aggregation process, aerosil nano-particles yield a fractal like surface pattern for the less disordered samples. As the aerosil dispersion increases, the surface can be described by more aggregated regions which also introduce more roughness. Using this fact, we have shown that there is a net correlation between the short-ranged x-ray peak widths (-the results of previous x-ray diffraction experiments-) and the calculated surface roughness. In other words, we have shown that these QRD gels can also be characterized by their surface roughness values.

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Sintering process of amorphous SiO2 nanoparticles investigated by AFM, IR and Raman techniques

Cited by 19 publications

References 21 publications

Tracing the status of silica fume in cementitious materials with Raman microscope

Tracing the status of silica fume in cementitious materials with Raman microscope

Optical trapping and Raman spectroscopy of solid particles

Roughness as a measurement of random disorder

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