Effect of the type of reducing agents of silver ions in interpolyelectrolyte-metal complexes on the structure, morphology and properties of silver-containing nanocomposites

V Demchenko,M Shut,S Riabov,S Kobylinskyi,N Rybalchenko,A Kruk,O Moskalenko,L Goncharenko

doi:10.1038/s41598-020-64079-0

Abstract

The objective of this work is to study the peculiarities of structural organization, morphology, thermomechanical, electrical and antimicrobial properties of nanocomposites based on pectin-polyethyleneimine interpolyelectrolyte complexes and silver nanoparticles in dependence on the type of reducing agent being applied for chemical reduction of silver ions in the interpolyelectrolyte-metal complexes. The average size of Ag nanoparticles is shown to be increased with decreasing of the activity of reducing agent (E0) and equals to 3.8 nm, 4.3 nm, and 15.8 nm, respectively, when engaging sodium borohydride (–1.24 V), hydrazine (–1.15 V) and ascorbic acid (–0.35 V). Moreover, it was found that the crystallite size of Ag nanoparticles also had the smallest value for nanocomposites obtained involving NaBH4 as reducing agent. Ag-containing nanocomposites prepared by reduction of silver ions in interpolyelectrolyte-metal complexes while applying a range of reducing agents are characterized by different electrical properties and polymer matrix’ glass transition temperature. The influence of silver nanoparticles’ size incorporated in the polymer matrix on the antimicrobial activity of nanocomposites has been established. The inhibition zone diameter of Staphylococcus aureus and Escherichia coli was higher for nanocomposites obtained using sodium borohydride and hydrazine compared to nanocomposites where ascorbic acid was used as the reducing agent.

Highlights

The objective of this work is to study the peculiarities of structural organization, morphology, thermomechanical, electrical and antimicrobial properties of nanocomposites based on pectinpolyethyleneimine interpolyelectrolyte complexes and silver nanoparticles in dependence on the type of reducing agent being applied for chemical reduction of silver ions in the interpolyelectrolyte-metal complexes
The aim of this work is to study the features of the structural organization, thermomechanical, electrical and antimicrobial properties of nanocomposites based on interpolyelectrolyte complexes comprising natural and synthetic components as well as the Ag nanoparticles fabricated by chemical reduction of silver ions with different reducing agent
The analysis of wide-angle X-ray patterns (Fig. 1, curve 1) has shown that stoichiometric interpolyelectrolyte complexes (IPEC) formed by the equimolar quantity of anionic and cationic polyelectrolytes, namely pectin and PEI, is characterized by short-range ordering during translation of fragments of oppositely charged polyelectrolytes’ macromolecular chains in space

Summary

Introduction

The objective of this work is to study the peculiarities of structural organization, morphology, thermomechanical, electrical and antimicrobial properties of nanocomposites based on pectinpolyethyleneimine interpolyelectrolyte complexes and silver nanoparticles in dependence on the type of reducing agent being applied for chemical reduction of silver ions in the interpolyelectrolyte-metal complexes. The average size of Ag nanoparticles is shown to be increased with decreasing of the activity of reducing agent (E0) and equals to 3.8 nm, 4.3 nm, and 15.8 nm, respectively, when engaging sodium borohydride (–1.24 V), hydrazine (–1.15 V) and ascorbic acid (–0.35 V). Ag-containing nanocomposites prepared by reduction of silver ions in interpolyelectrolyte-metal complexes while applying a range of reducing agents are characterized by different electrical properties and polymer matrix’ glass transition temperature. In[12] authors shown that average particles size of Ag formed, when adding Tween-20 as stabilizer, was 50 nm and 80 nm, implying sodium borohydride and hydrazine as reducing agents, respectively. In general[13], average particle size of Ag turned out to be smaller when applying NaBH4, but it depends on various factors, namely, molar ratio of silver to a reducing agent and capping agent, pH, temperature etc. Interpolyelectrolyte complexes allow to stabilize nanoparticles in the polymer matrix, protecting them from aggregation processes[4]

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