Synthesis of mono-dispersed nanofluids using solution plasma.

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Gold nanoparticles (NPs) are crucial for nanofluidics and heat transfer applications.
• Controlling NP size and dispersion is key to optimizing their performance.
• Solution plasma processing (SPP) offers a novel method for NP synthesis.

Purpose of the Study:

• To synthesize small, well-dispersed gold nanoparticles using SPP.
• To investigate the influence of SPP parameters on gold NP characteristics.
• To evaluate the thermal conductivity enhancement of nanofluids containing these gold NPs.

Main Methods:

• Gold nanoparticles were synthesized via electrical discharge in a liquid environment (SPP).
• The effect of solution temperature on NP size was studied, with 20°C yielding the smallest diameter (4.9 nm).
• Nucleation and growth theory were applied to model NP evolution.
• Zeta potential measurements were used to assess NP stability and dispersion.

Main Results:

• Small (4.9 nm) and well-dispersed gold NPs were successfully synthesized.
• Negative surface charges on NPs prevented agglomeration.
• Higher SPP energy led to decreased zeta potential and increased NP diameter.
• A 9.4% enhancement in thermal conductivity was observed in nanofluids with the smallest NPs.

Conclusions:

• SPP is an effective method for producing stable, small gold nanoparticles.
• Optimizing SPP conditions, particularly temperature, is crucial for controlling NP size.
• The synthesized gold NPs show significant potential for improving thermal conductivity in nanofluids.