Synthesis of Colloidal Au Nanoparticles through Ultrasonic Spray Pyrolysis and Their Use in the Preparation of Polyacrylate-AuNPs’ Composites

Abstract

Colloidal gold nanoparticles (AuNPs) were prepared from two different liquid precursors (gold (III) acetate and gold (III) chloride), using the Ultrasonic Spray Pyrolysis (USP) process. The STEM characterisation showed that the AuNPs from gold chloride are spherical, with average diameters of 57.2 and 69.4 nm, while the AuNPs from gold acetate are ellipsoidal, with average diameters of 84.2 and 134.3 nm, according to Dynamic Light Scattering (DLS) measurements. UV/VIS spectroscopy revealed the maximum absorbance band of AuNPs between 532 and 560 nm, which indicates a stable state. Colloidal AuNPs were used as starting material and were mixed together with acrylic acid (AA) and acrylamide (Am) for the free radical polymerization of polyacrylate-AuNPs’ composites, with the purpose of using them for temporary cavity fillings in the dental industry. SEM characterisation of polyacrylate-AuNPs’ composites revealed a uniform distribution of AuNPs through the polymer matrix, revealing that the AuNPs remained stable during the polymerization process. The density measurements revealed that colloidal AuNPs increase the densities of the prepared polyacrylate-AuNPs’ composites; the densities were increased up to 40% in comparison with the densities of the control samples. A compressive test showed that polyacrylate-AuNPs’ composites exhibited lower compressive strength compared to the control samples, while their toughness increased. At 50% compression deformation some of the samples fracture, suggesting that incorporation of colloidal AuNPs do not improve their compressive strength, but increase their toughness significantly. This increased toughness is the measured property which makes prepared polyacrylate-AuNPs potentially useful in dentistry.

Plasmonic Gold Nanoparticles (AuNPs): Properties, Synthesis and their Advanced Energy, Environmental and Biomedical Applications

“…The ultrasonication can be effectively combined with various synthetic techniques to achieve more fruitful results, such as electrochemical, [77] solvothermal [78,79], and sol-gel methods. [74,80,81] Mechanistically, the sonochemical effect generates the pressure during the reaction inside the reaction vessel and mixture because of the acoustic cavitation, which produces collapsing bubbles and ultimate pressure with high temperature as reported by Khan et al in the case of BiVO 4 . [79,82] This pressure, in turn, dissociates the water into reactive two primary radicals, i. e. H .…”

“…Unlike the seed‐mediated and other chemical preparation methods, here we do not need to use capping agents. The ultrasonication can be effectively combined with various synthetic techniques to achieve more fruitful results, such as electrochemical, [77] solvothermal [78,79], and sol‐gel methods [74,80,81] . Mechanistically, the sonochemical effect generates the pressure during the reaction inside the reaction vessel and mixture because of the acoustic cavitation, which produces collapsing bubbles and ultimate pressure with high temperature as reported by Khan et al.…”

Advances in Ultrasonic Spray Pyrolysis Processing of Noble Metal Nanoparticles—Review

“…For Au nanoparticles (AuNPs) we have also investigated extensively the cytotoxic and immunomodulatory properties of these particles for biomedical applications [31][32][33], as well as their behaviour when exposed to in situ heating during TEM observation [34], and their use in printing inks for Electronics (not yet published). We have also applied Au and ZnO nanoparticles in PMMA composites for advanced dental materials for removable prostheses [35]. The Ag/TiO 2 and Au/TiO 2 particles were produced for use as catalysts, and rare earth metals for photocatalytic applications [36,37].…”

Low-cost synthesis of AuNPs through ultrasonic spray pyrolysis

“…Frens et al improved this method further by varying different parameters, and produced different sizes of AuNPs successfully from 15 nm to 150 nm [37]. The literature reveals the synthesis of AuNPs using commercially available HAuCl 4 powders [38][39][40][41]. However, in the markets, these available precursors are very expensive to make AuNPs for scale-up production.…”