Two Highly Stable Silver Nanoparticles: Surface Plasmon Resonance Spectra Study of Silver Nanoparticles Capped with m-Hydroxybenzoic Acid and p-Hydroxybenzoic Acid

Gusrizal Gusrizal,Eko Sri Kunarti,Sri Juari Santosa,Bambang Rusdiarso

doi:10.20884/1.jm.2018.13.1.424

Abstract

Silver nanoparticles capped with m-hydroxybenzoic acid and p-hydroxybenzoic have been successfully synthesized, but the long-term stability data of these silver nanoparticles are not available. In this paper, we report the stability of these two types of silver nanoparticles for a period of 40 weeks observation based on the change of surface plasmon resonance spectra of silver nanoparticles. Silver nanoparticles were synthesized by reduction of silver nitrate with m-hydroxybenzoic acid and p-hydroxybenzoic acid without addition of capping agent. The presence of silver nanoparticles was indicated by the appearance of yellow color due to the surface plasmon resonance of silver nanoparticles. The resulted silver nanoparticles were stored at room temperature and further UV-visible spectrophotometer was used to follow the change in surface plasmon resonance spectra. The surface plasmon resonance spectra of silver nanoparticles were overlapped for the first 18 weeks, followed by little change in the position of absorption maxima (lmax), peak intensity, and width of the absorption peak until the week of 40. Silver nanoparticles capped with m-hydroxybenzoic acid and silver nanoparticles capped with p-hydroxybenzoic acid were highly stable which should make them suitable for further applications. The results show the potential of m-hydroxybenzoic acid and p-hydroxybenzoic acid to become a new reducing agent in the synthesis of highly stable silver nanoparticles. The m-hydroxybenzoic acid and p-hydroxybenzoic acid appeared to act as both reducing and capping agent.

Highlights

Over the past few years, the scientific publication shows a meaningful increase of research in exploring nanoparticles
Silver ion is reduced through hydroxyl phenolic group and resulted silver nanoparticles are capped with hydroxybenzoic acid through its carboxylic group
Calculation the average particles size from size distribution according to the transmission electron microscopy (TEM) image resulted in the average size of 31±15 and 32±12 nm for silver nanoparticles synthesized using m-hydroxybenzoic acid and phydroxybenzoic acid respectively

Summary

Introduction

Over the past few years, the scientific publication shows a meaningful increase of research in exploring nanoparticles. The interest in nanoparticles is resulted from the unique properties at nanoscale that not found in their bulk material with the same chemical composition. These properties include high surface to volume ratio, high surface energy, unique mechanical, magnetic, electrical, thermal, and optical behavior (Chen, Roy, Yang, & Prasad, 2016). Silver nanoparticles have received much attention among the metal nanoparticles. The characteristic features of silver nanoparticles are the presence of an intense and broad absorption peak in the visible range which called surface plasmon resonance spectra. The spectra stem from the interaction of light incident on the nanoparticles with the conduction electron of the metal and it depends on the size, shape, and media of the nanoparticles (Krutyakov, Kudrinskiy, Olenin, & Lisichkin, 2008; Mock, Barbic, Smith, Schultz, & Schultz, 2002)

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