Promotion of nucleation for nano-particle formation by two-stage microwave irradiation

Promoting Nucleation in Microwave‐Assisted Nanoparticle Synthesis Using Combined Two‐Stage Irradiation and Anti‐Solvent Addition

“…These may be strongly related to the presence of denser particles of quick thermal response. Since nucleation was greatly promoted by higher power of the first irradiation, energy from the second irradiation can be well‐distributed to more number of particles . Consequently, solvent evaporation around each particle requires less energy.…”

“…Past studies have revealed that there are proportional relations between better nanoparticle formation and higher irradiation power . However, some researchers reported that despite preferable higher power operation, exposure to high irradiation power especially at longer duration may result in superheating . While local heating or hot spot created by superheating may be a favorable condition for rapid nanoparticle growth rate, superheating is undesirable due to aggregation and degradation of the particle property because of sintering or melting .…”

“…Controlling suspension density (initial solute concentration) particularly at higher density had tested as one of the proposed solutions to inhibit superheating and the results were positive . Then, two‐stage irradiations (high power in the first stage and lower power in the second stage) were also found to be promising to prevent superheating . Compared to continuous microwave operation, two‐stage irradiation approach demonstrated the effectiveness for obtaining fine particles to some extent because absorbance energy per particle became lower.…”

Intensified Nanoparticle Synthesis Using Hybrid Microwave and Ultrasound Treatments: Consecutive and Concurrent Modes

“…In our previous studies, [ 35–39 ] microwave‐assisted nanoparticle formation was also found to be an effective process intensification technique in obtaining mono‐disperse fine particles. For nanoparticle synthesis, microwave heating is favorable compared to conventional heating due its rapid heating resulting to shorter operating time, homogeneous nucleation, higher yield and purity and more environmentally friendly, energy efficient and cost‐effective process.…”

“…For nanoparticle synthesis, microwave heating is favorable compared to conventional heating due its rapid heating resulting to shorter operating time, homogeneous nucleation, higher yield and purity and more environmentally friendly, energy efficient and cost‐effective process. [ 35 ] These advantages can be further promoted by two‐stage irradiation, [ 39 ] addition of anti‐solvent [ 37 ] and hybrid two‐stage irradiation and anti‐solvent addition [ 38 ] to avoid superheating behaviors. Despite the proven benefits above, some issues pertinent to having more stable microwave operation still remain.…”