In this paper, new 1D nano-fibrous SiO₂ with functionalized surfaces is prepared. First, the effect of dispersion on the morphology and the surface properties of the silica SiO₂ compounds are investigated. Second, energy dispersive spectrometer (EDS) and variable pressure scanning electron microscope (VP-SEM) show typically pure and fibrous texture on the surface of SiO₂. Third, the presence of the bridging oxygen stretching vibration Si-O-Si, as well as the increase in the intensity ratio between Si-OH band and Si-O-Si are revealed by (FTIR) spectroscopy. Furthermore, X-ray diffraction (XRD) validates the conservation of the SiO lattice after chemical treatment through the KOH for both dispersed and non-dispersed samples. In addition, the shift of the XRD main peak (101) is in good agreement with the FTIR results showing the shift of Si-O-Si peak and the increase in the intensity ratio of Si-OH/Si-O-Si. The dispersed SiO₂ sample exhibits a promising functionalized surface with satisfactory results in terms of silica nanofibers crystallinity and chemical composition. As a result, gigh resolution transmission electron microscopy (HR-TEM) data corroborate the claim of the presence of SiO₂ nanofibers on the surface from 20 nm to 250 nm. New nano-fibrous SiO₂ surfaces will be used to improve interfacial bonding strength between SiO₂ compounds and polymer (or organic materials).

Hybrid composites based on tin chloride and the conductive polymers, polyaniline (PAni) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), were integrated into high-performance hydrogen sulphide (H2S) gas sensors working at room temperature. The morphology and chemical properties were studied by scanning and transmission electron microscopy (SEM, TEM), energy dispersive spectroscopy (EDS) and Fourier-transform infrared (FTIR). The composites demonstrated a slightly porous nanostructure and strong interactions between the polymers and the metal salt, which slightly dopes PAni. The hybrid sensors exhibited a very low detection limit (<85 ppb), fast response, repeatability, reproducibility and stability over one month. Moreover, this work presents how calibration based on the derivative of the signal can give hybrid sensors the ability to quantify the concentration of targeted gas, even during continuous variation of the analyte concentration. Finally, the effect of interfering species, such as water and ammonia, is discussed.

In order to extend their use, controlled SiOH SiO₂ surfaces were fabricated and investigated. A study of the effect of heat treatment on the structural and surface changes of a natural flint SiO₂ aggregate subjected to chemical treatment was carried out. The obtained samples were subjected to thermal treatment at three different temperatures: 500, 700, and 1000 °C. The samples were investigated using different techniques. X-ray diffractions (XRD) were used to follow the structure’s evolution with the heat treatment. The decrease in the FWHM of the SiO₂-(101) peak showed that the crystalline quality improved upon heating. This result was confirmed by Fourier transform infrared spectroscopy (FTIR). The morphology of the SiO₂ samples was characterized using a Variable Pressure scanning electron microscope (VP-SEM), revealing the presence of disordered needles of nanometric sizes (∼500 nm) on the surface of the grains, which could be eliminated by heating at higher temperatures. Furthermore, FTIR spectroscopy also confirmed that heating caused a reduction in OH groups on the surface. Thermogravimetry (TG) was used as the reference method to determine the hydroxyl group content. The OH groups found on the surface of the sample without and with heat treatment at 500, 700, and 1000 °C were 0.83, 0.44, 0.28, and 0.2 mmol/g, respectively. This study allowed us to obtain a controlled SiO₂ surface and provides new insights into the use of SiO₂ flint surfaces for new applications as a functional filler in polymers/asphalts composites.

This study introduces a novel method to analyze how fillers disperse in bituminous binders. A custom-designed laboratory setup enables precise temperature control (140 °C) and mixing speeds (200, 800, 1500 rpm) for small-scale mixtures (5% filler) over 5, 15 and 30 min. To assess dispersion, microscopy-based visualization approach using optical microscopy (10× objective) and image analysis (ImageJ). Each particle is segmented and its projected area converted into an equivalent diameter, yielding a surface-fraction distribution (in logarithmic size bins). We evaluate the D₅₀ (Area50) position and the 50–100% range to detect coarse aggregates or over-shearing. The interest of the method is illustrated by comparing how limestone (CaCO₂) and quartz (SiO₂) fillers disperse in two different bitumens: naphthenic and paraffinic. Results indicate that quartz disperses more readily, quickly approaching a near-homogeneous state, whereas limestone requires higher shear and longer mixing times to approach the reference filler. Paraffinic bitumen shows a higher initial fine‑particle fraction; nonetheless, the naphthenic binder de‑agglomerates faster and ultimately matches, or slightly surpasses, the paraffinic dispersion. Mixing at 1500 rpm can fracture particles, skewing the size profile. The protocol delivers ± 1% repeatability across replicates, providing a robust tool for optimising mastic formulation and enhancing pavement durability.

Gaseous Scanning Electron Microscope (GSEM): Applications and Improvement | InTechOpen, Published on: 2012-03-09. Authors: Lahcen Khouchaf