Limits...
Fabrication, characterization, and thermal property evaluation of silver nanofluids.

Noroozi M, Radiman S, Zakaria A, Soltaninejad S - Nanoscale Res Lett (2014)

Bottom Line: The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP).Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water.The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia.

ABSTRACT
Silver nanoparticles were successfully prepared in two different solvents using a microwave heating technique, with various irradiation times. The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP). The optical properties, thermal properties, and morphology of the synthesized silver particles were characterized using ultraviolet-visible spectroscopy, photopyroelectric technique, and transmission electron microscopy. It was found that for the both solvents, the effect of microwave irradiation was mainly on the particles distribution, rather than the size, which enabled to make stable and homogeneous silver nanofluids. The individual spherical nanostructure of self-assembled nanoparticles has been formed during microwave irradiation. Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water. A photopyroelectric technique was carried out to measure thermal diffusivity of the samples. The precision and accuracy of this technique was established by comparing the measured thermal diffusivity of the distilled water and ethylene glycol with values reported in the literature. The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.

No MeSH data available.


TEM images and their size distributions of Ag NPs in EG at different MW irradiation time. 20 (A,B), 40 (C,D), 60 (E,F), and 90 s (G,H).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4256963&req=5

Figure 5: TEM images and their size distributions of Ag NPs in EG at different MW irradiation time. 20 (A,B), 40 (C,D), 60 (E,F), and 90 s (G,H).

Mentions: Figure 5 shows TEM images, and corresponding size distributions, for the Ag/EG nanofluids produced using various MW irradiation times. In the Ag NP solutions prepared using 20 and 40 s of MW irradiation, Ag NPs were formed with a broad size distribution, and the mean particle size was approximately 12.8 and 12.6 nm, respectively (Figure 5A,C). For the solutions irradiated for 60 and 90 s (Figure 5E,G), the mean Ag NP particle size was decreased, but there was evidence of small species, as well as large. This was probably because the excess Ag+ ions produced more nuclei during the nucleation period, thus leading to the formation of smaller NPs [15]. More NP nuclei are required during the reaction process for the formation of small NPs with a narrow size distribution. The number and size of the small nuclei formed are controlled by the properties of the solvent. As shown by the results for the Ag/EG nanofluids, the special properties of EG, including its high-loss dielectric nature, high molecular weight, and high boiling point, resulted in increases in the total volume of the nanocrystals, and decreases in the size of the NPs, with time. It can be seen that larger Ag NPs were obtained under shorter irradiation time, because usually more crystal nuclei were provided under further irradiation [16]. The TEM result of decreasing in the particle size of Ag NPs dispersed in EG at 90 s is in accordance with the blueshift of its absorption peak as shown in Figure 3.


Fabrication, characterization, and thermal property evaluation of silver nanofluids.

Noroozi M, Radiman S, Zakaria A, Soltaninejad S - Nanoscale Res Lett (2014)

TEM images and their size distributions of Ag NPs in EG at different MW irradiation time. 20 (A,B), 40 (C,D), 60 (E,F), and 90 s (G,H).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256963&req=5

Figure 5: TEM images and their size distributions of Ag NPs in EG at different MW irradiation time. 20 (A,B), 40 (C,D), 60 (E,F), and 90 s (G,H).
Mentions: Figure 5 shows TEM images, and corresponding size distributions, for the Ag/EG nanofluids produced using various MW irradiation times. In the Ag NP solutions prepared using 20 and 40 s of MW irradiation, Ag NPs were formed with a broad size distribution, and the mean particle size was approximately 12.8 and 12.6 nm, respectively (Figure 5A,C). For the solutions irradiated for 60 and 90 s (Figure 5E,G), the mean Ag NP particle size was decreased, but there was evidence of small species, as well as large. This was probably because the excess Ag+ ions produced more nuclei during the nucleation period, thus leading to the formation of smaller NPs [15]. More NP nuclei are required during the reaction process for the formation of small NPs with a narrow size distribution. The number and size of the small nuclei formed are controlled by the properties of the solvent. As shown by the results for the Ag/EG nanofluids, the special properties of EG, including its high-loss dielectric nature, high molecular weight, and high boiling point, resulted in increases in the total volume of the nanocrystals, and decreases in the size of the NPs, with time. It can be seen that larger Ag NPs were obtained under shorter irradiation time, because usually more crystal nuclei were provided under further irradiation [16]. The TEM result of decreasing in the particle size of Ag NPs dispersed in EG at 90 s is in accordance with the blueshift of its absorption peak as shown in Figure 3.

Bottom Line: The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP).Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water.The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia.

ABSTRACT
Silver nanoparticles were successfully prepared in two different solvents using a microwave heating technique, with various irradiation times. The silver nanoparticles were dispersed in polar liquids (distilled water and ethylene glycol) without any other reducing agent, in the presence of the stabilizer polyvinylpyrrolidone (PVP). The optical properties, thermal properties, and morphology of the synthesized silver particles were characterized using ultraviolet-visible spectroscopy, photopyroelectric technique, and transmission electron microscopy. It was found that for the both solvents, the effect of microwave irradiation was mainly on the particles distribution, rather than the size, which enabled to make stable and homogeneous silver nanofluids. The individual spherical nanostructure of self-assembled nanoparticles has been formed during microwave irradiation. Ethylene glycol solution, due to its special properties, such as high dielectric loss, high molecular weight, and high boiling point, can serve as a good solvent for microwave heating and is found to be a more suitable medium than the distilled water. A photopyroelectric technique was carried out to measure thermal diffusivity of the samples. The precision and accuracy of this technique was established by comparing the measured thermal diffusivity of the distilled water and ethylene glycol with values reported in the literature. The thermal diffusivity ratio of the silver nanofluids increased up to 1.15 and 1.25 for distilled water and ethylene glycol, respectively.

No MeSH data available.