Three strategies to stabilise nearly monodispersed silver nanoparticles in aqueous solution
1 Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
2 Department of Materials, National Centre for Scientific Research, PO Box 6414, Avenida 25 and 158, Cubanacán, Playa, Havana, CP 12100, Cuba
3 Department of Statistics, University of Barcelona, Avenida Diagonal 645, Barcelona, 08028, Spain
4 Institute of Nanoscience for Medicine, Oxford Martin School, 34 Broad Street, University of Oxford, Oxford, OX1 3BD, UK
Nanoscale Research Letters 2012, 7:151 doi:10.1186/1556-276X-7-151Published: 22 February 2012
Silver nanoparticles are extensively used due to their chemical and physical properties and promising applications in areas such as medicine and electronics. Controlled synthesis of silver nanoparticles remains a major challenge due to the difficulty in producing long-term stable particles of the same size and shape in aqueous solution. To address this problem, we examine three strategies to stabilise aqueous solutions of 15 nm citrate-reduced silver nanoparticles using organic polymeric capping, bimetallic core-shell and bimetallic alloying. Our results show that these strategies drastically improve nanoparticle stability by distinct mechanisms. Additionally, we report a new role of polymer functionalisation in preventing further uncontrolled nanoparticle growth. For bimetallic nanoparticles, we attribute the presence of a higher valence metal on the surface of the nanoparticle as one of the key factors for improving their long-term stability. Stable silver-based nanoparticles, free of organic solvents, will have great potential for accelerating further environmental and nanotoxicity studies.
PACS: 81.07.-b; 81.16.Be; 82.70.Dd.