Process for preparing nanoparticles
A process for producing nanoparticles comprises the steps of preparing silver seeds in the presence of a water soluble polyanionic polymer and growing the silver seeds to form nanoparticles. The polyanionic polymer may be poly(sodium styrenesulphonate).
1. A process for producing nanoparticles comprising the steps of:
preparing silver seeds by combining aqueous solutions consisting essentially of trisodium citrate, sodium borohydride, and a water soluble polyanionic polymer selected from the group consisting of: a derivative of an inorganic salt of poly(styrene sulphonate); a copolymer of poly(sodium styrene sulphonate-co-maleic acid); a derivative of poly(anethole sulphonate); a derivative of poly(vinyl sulphate); or a derivative of poly(vinyl sulphonate); and subsequently adding aqueous silver nitrate; and
growing the silver seeds to form nanoparticles, the growing of the silver seeds taking place at room temperature using water as a solvent, greater than about 95% of the nanoparticles thus produced being nanoprisms.
2. The process as claimed in claim 1 wherein the polymer is a derivative of a monovalent salt of poly(styrene sulphonate).
3. The process as claimed in claim 1 wherein the polymer is poly(sodium styrene sulphonate) (PSSS).
4. The process as claimed in claim 3 wherein the PSSS has a molecular weight between about 3 KDa to about 1,000 KDa.
5. The process as claimed in claim 3 wherein the PSSS has a molecular weight of about 1,000 KDa.
6. The process as claimed in claim 1 wherein the polymer is poly(sodium anethole sulphonate).
7. The process as claimed in claim 1 wherein the polymer is poly(potassium vinyl sulphate).
8. The process as claimed in claim 1 wherein the polymer is poly(sodium vinyl sulphonate).
9. The process as claimed in claim 1 wherein the concentration of polymer in the silver seed preparation is between about 0.2 mg/l to about 2 g/l.
10. The process as claimed in claim 1 wherein the concentration of polymer in the silver seed preparation is about 12.5 mg/l.
11. The process as claimed in claim 1 wherein the step of growing the silver seeds involves the silver seed-catalysed reduction of Ag + by ascorbic acid.
12. A process for producing nanoparticles comprising the steps of:
preparing silver seeds in the presence of a water soluble polyanionic polymer wherein the polymer is selected from the group consisting of: poly(sodium anethole sulphonate), poly(potassium vinyl sulphate), and poly(sodium vinyl sulphonate); and
growing the silver seeds to form nanoparticles, the growing of the silver seeds taking place at room temperature using water as a solvent, greater than about 95% of the nanoparticles thus produced being nanoprisms.