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Licensed Unlicensed Requires Authentication Published by De Gruyter May 23, 2016

Antibacterial activity and nanocomposite properties of monodispersed silver nanoparticles synthesized by the microwave method

Antibakterielle Aktivität und Nanokomposit-Eigenschaften von monodispersiven Silberpartikeln synthetisiert mittels Mikrowelle
  • Anchaleeporn W. Lothongkum , Kornwika Wongparb , Pinthep Sethapokin and Sutichai Chaisitsak
From the journal Materials Testing


Monodispersed colloidal silver nanoparticles (Ag-NPs) were synthesized by a simple and rapid microwave method. A precursor, AgNO3, was reduced by ethylene glycol (EG) and N,N-dimethylformamide (DMF) in the presence of polyvinylpyrrolidone (PVP) as a stabilizer or capping agent. It was found that the concentration of AgNO3 significantly affected Ag-NPs particle sizes. The particle sizes decreased when the concentration decreased from 0.1 to 0.05 and 0.01 M, which corresponded to narrow size distribution of the particle diameters of approximately 60 to 80, 30 to 40 and 10 to 20 nm. The spherical-shaped monodispersed Ag-NPs were obtained by using a volume ratio of EG to DMF of 2.75 : 2.25, microwave power of 400 W and heating time of 2 min. The volume ratio of EG to DMF and the microwave power influenced the uniformity of the Ag-NPs shape and size, while the heating time had no effect. For antibacterial application, 60–80 and 10–20 nm Ag-NPs showed good disinfection ability against Escherichia coli (ATCC 25922) at the minimum inhibitory concentrations (MIC) of 32 and 16 µg × ml−1, respectively. In addition, the electrical resistance of the nanocomposites of DMF-loaded Ag-NPs (20–50 nm) without PVP on single-walled carbon nanotubes and polyethylene terephthalate (PET) was measured. As a result, it is obvious that the Ag-NPs help to increase the electrical conductivity of the nanocomposites as the electrical resistance of the Ag-NPs nanocomposites was 4.68 kΩ × cm−2 compared to that of the nanocomposites without Ag-NPs of 8.76 kΩ × cm−2.


In der diesem Beitrag zugrunde liegenden Studie wurden monodispersive kolloidale Silberpartikel (Ag-NPs) mittels eines einfachen und schnellen Mikrowellenverfahrens synthetisiert. Hierzu wurde ein Precursor, AgNO3, mittels Ethylenglykol (EG) und N,N-Dimethylformamid (DMF) reduziert, und zwar in Anwesenheit von Polyvinylpyrrolidon (PVP) als Stabilisator oder Abdeckreagenz. Es stellte sich heraus, dass mit der Konzentration von AgNO3 die Partikelgröße der Ag-NPs signifikant beeinflusst wird. Die Partikelgrößen nahmen ab, als die Konzentration von 0,1 auf 0,05 bzw. 0,01 M abnahm, wobei die enge Größenverteilung der Partikeldurchmesser von ungefähr 60 bis 80, 30 bis 40 und 10 bis 20 nm korrespondierte. Die kugelförmigen monodispersiven Ag-NPs wurden bei einem Volumenverhältnis EG zu DMF von 2.75 : 2.25, einer Mikrowellenleistung von 400 W und einer Wärmedauer von 2 min gewonnen. Das Volumenverhältnis von EG zu DMF und die Mikrowellenleistung beeinflusste die Gleichförmigkeit der Ag-NPs hinsichtlich Form und Größe, während die Erhitzungszeit keinen Einfluss hatte. Für antibakterielle Anwendungen zeigten die 60 bis 80 und 10 bis 20 nm Ag-NPs gute Desinfektionseigenschaften gegen Escherichia coli (ATCC 25922) bei minimalen inhibierenden Konzentrationen (Minimum Inhibitory Concentrations (MIC)) von entsprechend 32 und 16 µg × ml−1. Darüber hinaus wurde der elektrische Widerstand der Nanokomposite der DMF-geladenen Ag-NPs (20 bis 50 nm) ohne PVP auf einwandigen Carbon-Nanoröhrchen und Polyethylen-Terephthalat (PET) gemessen. Als ein Ergebnis stellte sich heraus, dass die Ag-NPs offensichtlich helfen, die elektrische Leitfähigkeit der Nanokomposite zu erhöhen, zumal der elektrische Widerstand der Ag-NPs Nanokomposite 4.68 kΩ × cm−2 betrug, wohingegen die Nanokomposite ohne Ag-NPs einen elektrischen Widerstand von 8.76 kΩ × cm−2 aufweisen.

*Correspondence Address, Assoc. Prof. Dr. Anchaleeporn W. Lothongkum, Department of Chemical Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand. E-mail: ,

Associate Prof. Dr. Anchaleeporn Waritswat Lothongkum received her BSc in Chemical Engineering from Chulalongkorn University, Thailand, in 1983, and her MEng in Chemical Engineering from the same university in 1987. She received a scholarship from UDC from the Ministry of University Affairs and achieved her PhD in Hydrocarbon Chemistry: Catalyst Design Engineering at Kyoto University, Japan, in 1994, by a Scholarship from the Hitachi Scholarship Foundation. She has been Associate Professor at King Mongkut's Institute of Technology Ladkrabang in Bangkok, Thailand, and the President of the Thai Institute of Chemical Engineering and Applied Chemistry since 2013. Her fields of interest are catalysis, clean technologies, alternative energy, sol gel technology, membrane technology, separation processes, environmental related, corrosion, wastewater treatment, adsorption engineering, electroplating and powder technology.

Kornwika Wongparb, born in 1988, received her BEng and MEng in Chemical Engineering from King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand with a focus on nanocomposite materials and graduated in 2010 and 2013, respectively. She has been employed as a process engineer at Siam City Cement Public Company Limited, Thailand, since 2015.

Dr. Pinthep Sethapokin, born in 1987, received his BEng and has a PhD earned by a scholarship from The Royal Golden Jubilee PhD from The Thailand Research Fund in Chemical Engineering from King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand in 2009 and 2015, respectively. His fields of interest are catalysis, process simulation and optimization.

Associate Prof. Dr. Sutichai Chaisitsak, born in 1973, received his BEng in Electronic Engineering from Nagoya University in Japan in 1997, his MEng in Physical Electronic Engineering and his PhD in Electrical and Electronic Engineering from the Tokyo Institute of Technology in Japan in 1999 and 2002, respectively. After his postdoctoral research with Prof. Makoto Konagai and Prof. Akira Yamada at the Tokyo Institute of Technology, he joined the King Mongkut's Institute of Technology Ladkrabang in Bangkok, Thailand, as a lecturer in 2003. In 2008 he became Associate Professor in the Department of Electronics Engineering in. He is the Head of the Laboratory of Nano Electronic Materials and Devices. His current research interests are solar cells, energy conversion devices using nanomaterials, carbon nanostructures (single-walled carbon nanotubes, graphene) for electronic applications and gas sensors based on metal oxide nanostructures.


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Published Online: 2016-05-23
Published in Print: 2016-06-01

© 2016, Carl Hanser Verlag, München

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