Polymer-dispersant-stabilized Ag nanofluids for heat transfer applications

K S Pavithra,S C Gurumurthy,Koduri Ramam,M S Murari,Tarun Mateti,M P Yashoda,Roopa Nayak

doi:10.1007/s10973-020-10064-8

Abstract

One-step wet chemical method has been employed for the synthesis of silver (Ag) nanofluids followed by the preparation of polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and PVP–PVA mixed-dispersant-stabilized nanofluids by varying the concentration ratio of dispersants for the viscosity and thermal conductivity analysis. The optical absorption studies indicate the presence of nanoparticles in the prepared fluids (or the formation of the silver nanoparticles). The shape and size of the nanoparticles are confirmed by the field emission scanning electron microscopy, and the particle size distribution and zeta potential analysis were carried out by using dynamic light scattering. It is observed that the thermal conductivity of Ag nanofluids increases with an increase in the dispersant concentration with respect to the temperature. The maximum thermal conductivity enhancement of Ag nanofluids was observed in the presence of an equimolar ratio of PVP–PVA (1:1:1) blends as stabilizers.Graphic abstract

Highlights

In recent advancements in technologies and industrial applications, there is a need for the development of highly efficient heat transfer and cooling devices
The UV–Vis absorption spectra for Ag nanofluids recorded by Absorbence/a.u
In the case of polyvinyl alcohol (PVA)-stabilized Ag nanofluids, it exhibits a characteristic absorption maximum at 429 nm corresponding to − ∗ electronic transitions, whereas a relatively weak absorption maximum at 421 nm for PVPstabilized Ag nanofluids is mainly attributed to the n − ∗, the electronic transition between the lone pair of oxygen and the vacant ∗ orbital of the pyrrolidone ring

Summary

Introduction

In recent advancements in technologies and industrial applications, there is a need for the development of highly efficient heat transfer and cooling devices. Nanofluids are a colloidal suspension of ultrafine solid nanoparticles (NPs) like Cu, Zn, Ag, ZnO, CuO, T iO2, etc., into the conventional heat transfer fluids like ethylene glycol, water, and engine oils. It has been proved as one of the efficient ways to improve the thermal performance of the system by the addition of NPs into the conventional fluids, and it is considered as one of the significant potential materials for heat transfer applications. Among the metal NPs, Ag NPs have attracted the attention of researchers for the preparation of nanofluids mainly due to their environmentally friendly and unique thermal properties. The stability of nanofluids is one of the critical issues and the main challenge to be solved for many applications [10]

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Results

Conclusion