Polymer-dispersant-stabilized Ag nanofluids for heat transfer applications

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