Ionic Strength-Controlled Deposition of Charged Nanoparticles on a Solid Substrate
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- 作者：Katarzyna Winkler ; Maciej Paszewski ; Tomasz Kalwarczyk ; Ewelina Kalwarczyk ; Tomasz Wojciechowski ; Ewa Gorecka ; Damian Pociecha ; Robert Holyst ; Marcin Fialkowski
- 刊名：Journal of Physical Chemistry C
- 出版年：2011
- 出版时间：October 6, 2011
- 年：2011
- 卷：115
- 期：39
- 页码：19096-19103
- 全文大小：967K
- 年卷期：v.115,no.39(October 6, 2011)
- ISSN：1932-7455
文摘
There is experimental evidence that in solutions of low ionic strength, charged nanoparticles (NPs) adsorbing onto an oppositely charged substrate cannot form dense monolayers due to the electrostatic repulsion. Here, we investigated the adsorption onto negatively charged substrates occurring in solutions containing positively charged NPs and salt for a wide range of ionic strengths. We found that the salt added in high concentration, above 2M, stabilizes the solution and the NPs adsorb on the substrate to form dense coatings characterized by the surface coverage of about 50%. In this regime, the adsorption rate was found to grow with the square of the NP concentration. This effect of salt on the deposition process provides a facile method of coating of solid substrates with NP monolayers. The density of such monolayers depends on and can be easily controlled by the deposition time, as well as by the salt and NP concentration in the plating solution.