Investigation of Metallic Silver Nanoparticles through UV-Vis and Optical Micrograph Techniques

Abstract

In this work, UV-Vis and optical micrograph techniques were used to characterize the reduced silver nanoparticles in chitosan polymer doped with AgNO3 salt. The UV-Vis spectrum shows distinguishable surface plasmonic resonance (SPR) absorption peaks at about 430 nm for the samples containing different amount of silver salt. The SPR peaks indicate the existence of silver nanoparticles. Upon the increase of silver nitrate salt concentration, the SPR peak intensity is enhanced, indicating the reduction of large amount of silver ions to the metallic silver nanoparticles in chitosan (CS) host polymer. Optical micrograph results show that silver nanoparticles are well dispersed at low silver salt concentrations. A leakage of large white spots of silver nanoparticles was observed at a higher silver salt concentration. The effect of lattice energy of silver salts on silver ion reduction and its distribution is interpreted. The FE-SEM image shows small white spots of silver nanoparticles on the surface of the sample. The observed shift in the Fourier transform infrared (FTIR) bands of CS:AgNO3 relative to that of pure CS indicates the complexation between the chitosan polymer and the silver nitrate salt.

Morphological and Optical Characteristics of Chitosan(1−x):Cuox (4 ≤ x ≤ 12) Based Polymer Nano-Composites: Optical Dielectric Loss as an Alternative Method for Tauc’s Model

“…It is clear from the figures that, at high CuI concentration, white chains and spots with different sizes can be observed on the surface of the CS nanocomposite samples. Earlier studies have confirmed that the use of SEM and EDAX techniques are sufficient to detect the formation of plasmonic metal nanoparticles in polymer composites [13,14,15,17,18]. The EDAX taken for the CSN2 sample focusing on the aggregated white spots is illustrated in Figure 1D, which shows the existence of significant amounts of metallic Cu particles.…”

“…The amine (NH 2 ) and hydroxyl (OH) functional groups on the CS backbone structure explain its ability to form complexes with inorganic salts [12]. Previous studies confirmed that the existences of lone pair electrons on chitosan functional groups are found to be responsible for complexation as well as reduction of silver ions to silver nanoparticles [14,15,16,17,18]. However, such problem can be overcome by the use of in-situ technique [19].…”

New Method for the Development of Plasmonic Metal-Semiconductor Interface Layer: Polymer Composites with Reduced Energy Band Gap

“…Polymers, such as CS, poly(ethylene oxide) (PEO), poly(2-ethyl-2-oxazoline) (POZ), and poly(vinyl pyrrolidone) (PVP), containing polar 2 Journal of Nanomaterials groups have been introduced as a polymer solvent for the silver salts to be dissolved [12]. Earlier works established that lone-pair electrons on the functional groups of polar polymers are responsible for the complexation and reduction of silver ions to silver nanoparticles [13][14][15][16]. This phenomenon (i.e., Ag + → AgO) limits the application of silver-based ionconducting polymer electrolytes in electrochemical devices [17,18].…”

Multifunctional electrochromic energy storage devices by chemical cross-linking: impact of a WO3·H2O nanoparticle-embedded chitosan thin film on amorphous WO3 films

“…As shown in Fig. 1b, bare a-WO 3 gives rise to a broad diffraction peak centered at 23.1°, which is indicative of the presence of the a-WO 3 structure 29 . With the introduction of the chitosan thin film on a-WO 3 films (a-WO 3 /CH), there is a slight decrease in the diffraction intensity without structural variation of the a-WO 3 .…”