In this study, new composites based on polyvinylidene fluoride (PVDF) were ornamented and prepared with hydroxyapatite (HA) and silver nitride (AgNO₃). Taking into account the polarity of the solvent dimethyl sulfoxide, this solvent was used to disperse the particles. The aim of using DMSO was to create amorphous phases and the strong dipoles of the C–F bond to reduce the energy barrier and improve the electrical properties. The PVDF played the role of matrix in HA, and AgNO₃ was used as reinforcing elements. X-ray diffraction of the samples directly showed the amorphous phase and mixed amorphous and crystalline phases when all three materials were used simultaneously for preparing the composite. The scanning electron microscopy (SEM) images of the samples confirmed the role of PVDF, HA, and AgNO₃. Furthermore, the energy dispersive X-ray (EDX) analysis was performed and proved that the HA structure did not change when the ratio of $\frac{\mathrm{Ca}}{\mathrm{P}}$ was equal to the ratio of natural HA. The electrical properties were investigated, and the amount of energy ranged from 56.50 to 125.20 mV. The final results showed that a designed device consisting of an active layer made of 0.1 g HA:0.5 g PVDF showed the highest energy barrier, the highest polarity, and surface energy, thus proving its relevance as potential material for energy harvesting applications.

Typically, polymer composites and ceramics are used to create biosensors. Materials with properties that are ideal for biosensors and chemical sensors include AgNO₃ (silver nitrate), PVDF (polyvinylidene fluoride), and HA (hydroxyapatite). Polyvinylidene fluoride (PVDF) polymer has been widely used in several applications because of its well-known superior ferroelectric characteristics and biocompatibility. The brittleness and low bending strength of hydroxyapatite limit its applicability. Several HA and polymer composite formulations have been developed to compensate for HA’s mechanical weakness. The final product contains a significant amount of HA, making HA/polymer composites highly biocompatible. When the right amount of silver is deposited, the maximum piezoelectric activity is generated, and silver nitrate has antimicrobial properties. The non-toxic solvent DMSO (dimethyl sulfoxide) and the solvent casting method were chosen for the preparation of the film. Surface roughness was chosen to measure the Str and Sdr properties of the thin film. For liquid preparation, the multifractal spectra analysis was chosen for each sample. SEM was used to examine the samples morphologically. EDX and mapping analyses were presented for chemistry distribution in the samples.

In this paper, a novel nanocrystalline composite material of hydroxyapatite (HA)/polyvinyltrimethoxysilane (PVTMS)/iron(II)chloride tetrahydrate (Cl₂FeH₈-O₄) with hexagonal structure is proposed for the fabrication of a gas/temperature sensor. Taking into account the sensitivity of HA to high temperatures, to prevent the collapse and breakdown of bonds and the leakage of volatiles without damaging the composite structure, a freeze-drying machine is designed and fabricated. X-ray diffraction, FTIR, SEM, EDAX, TEM, absorption and photoluminescence analyses of composite are studied. XRD is used to confirm the material structure and the crystallite size of the composite is calculated by the Monshi–Scherrer method, and a value of 81.60 ± 0.06 nm is obtained. The influence of the oxygen environment on the absorption and photoluminescence measurements of the composite and the influence of vaporized ethanol, N₂ and CO on the SiO₂/composite/Ag sensor device are investigated. The sensor with a 30 nm-thick layer of composite shows the highest response to vaporized ethanol, N₂ and ambient CO. Overall, the composite and sensor exhibit a good selectivity to oxygen, vaporized ethanol, N₂ and CO environments.