Comparison of direct synthesis of silver nanoparticles colloid using pullulan under conventional heating and microwave irradiation

In this comparative study, synthesis of pullulan-stabilized silver nanoparticles (AgNPs) colloid using conventional heating (CH) and microwave irradiation (MI) methods was investigated. The resulting AgNPs were characterized by UV-Vis, X-ray diffraction, and transmission electron microscopy. The reaction time and temperature were optimized for CH, and MI are 110°C, 40 min and 90°C, 10 min, respectively. The microwave-assisted approach improved pullulan/AgNPs colloid formation, with higher efficiency, shorter time, and lower temperature. However, the CH method produced more stable AgNPs with larger mean sizes. The antibacterial activities of the samples from CH and MI processes were compared.