The synthesis of alginate-capped silver nanoparticles under microwave irradiation

Synthesis of silver nanoparticles (ag-np) was successfully performed within a few minutes by microwave irradiation of the precursor salt (agno3) and alginate mixed solution in one pot. herein,alginate molecules acted as both a reducing and stabilizing agent for the preparation of the silver nanoparticles. the obtained nanoparticles were characterized by ultraviolet-visible (uv-vis) spectroscopy,particle size analysis (psa),fourier transform infrared spectroscopy (ftir),and transmission electron microscopy (tem). the ph and concentration ratio of the alginate/metal precursor salt greatly influenced the particle size and its distribution of ag-np. the higher the ph the higher the nucleation rate and the larger the electrostatic stabilization,while both of them were responsible for producing a smaller particle size and a narrower size distribution. a higher concentration ratio also yielded a smaller particle size and a narrower size distribution,but above the optimum ratio,the trend was conversely changed due to the reducing capability of the alginate,which was dominant above the optimum ratio,thus creating a high density of nuclei,allowing aggregation to occur. a lower ratio not only led to a higher tendency to produce larger particles,but also a higher probability of anisotropic particle shape formation due to the lack of reducing capability of the alginates. © 2015,published by itb journal publisher.