Silica nanocomposites based on silver nanoparticles-functionalization and pH effect

Abstract

Current reports in the field of nanotechnology indicate that the properties of metal nanoparticles are determined by their features such as size, shape, composition as well as a degree of crystallinity and stability. These, in turn, may depend heavily on their preparation way, treatment during and after synthesis and finally on properties of the supports and matrices. The goal of presented work was to determine the shape, size, and distribution of silver nanoparticles depending on preparation conditions. In particular, the issues of the formation of silver nanostructures (AgNP) with various shapes and sizes depending on functionalized silica surface as well as on the conditions of the impregnation step by noble metal ions (especially pH) were considered. In particular, the comprehensive approach to determine the impact of pH conditions on the properties of metallic nanoparticles is laid down in this work. Three types of fumed silica materials were selected as the supports of silver nanostructures (Aerosil 150, Aerosil 300 and Silochrom C-120). Silica materials were chemically functionalized by thiol and amine groups and treated with diamminesilver(I) ions [Ag(NH 3 ) 2 ] + . As a result of their reduction silicas adorned with silver nanostructures were obtained. In this work, the AgNP in the form of very small nanoparticles, longitudinal and spherical forms and greater structures with nondescript shape were successfully received and characterized through changing the form of functional groups on the solid surface by adjusting the pH conditions. It turns out that protonation and deprotonation of thiol, amino, and hydroxyl groups can be responsible for possible interactions between noble metal ions and functional groups in the form of both attractive and repulsive electrostatic interactions. The Ag nanoparticle/silica nanocomposites were investigated by X-ray diffraction, atomic force microscopy, potentiometric titration and X-ray photoelectron spectroscopy.

New Nanohybrid Based on Hydrolyzed Polyacrylamide and Silica Nanoparticles: Morphological, Structural and Thermal Properties

“…In these spectra, different signals attributed to the functional groups belonging to the functionalized NPs and nanohybrid (CSNH-PC1) are identified. The carbon-containing species identified were C-C at 285.39 eV, C-Si at 284.38 eV, and C=O around 287.6 eV [49].…”

Physical, mechanical, and antibacterial characteristics of bio‐nanocomposite films loaded with Ag‐modified SiO2 and TiO2 nanoparticles

“…The direct incorporation of metallic NPs into bio‐nanocomposite films would have health risks due to their toxicity to eukaryotic cells and their possible migration from food package to the food product (Dehghani et al., 2019). Surface modification or functionalization of inorganic NPs such as TiO 2 and SiO 2 is a strategy to improve several characteristics of bio‐nanocomposite matrix: (a) antimicrobial properties; (b) physical stability and dispersion of NPs; (c) Ag level, which is lower than that of Ag individually added, making modified NPs less toxic (Zienkiewicz‐Strzałka, Deryło‐Marczewska, & Kozakevych, 2018). Recently, Peter et al.…”

Electrochemical Detection of Arsenite Using a Silica Nanoparticles-Modified Screen-Printed Carbon Electrode

“…A further phenomenon worth noting is the range of pH in which the surface charge densities of amine-functionalized SiNPs influence the confrontation of As(III). The nanoparticles retain a net positive charge at pH values below 6.84 and carry a net negative charge at a higher pH (pH > 6.84) [35,36]. It is, therefore, predicted that negatively charged arsenite ions could be effectively migrated to the electrode surface under acidic conditions.…”