Evolution of Micron-Spaced Patterns within Precipitating Patterns of In Situ Synthesized Silver Nanoparticles in a Nanodot-Embedded PVA/PVP Film.

Abstract

Periodic pattern formation beyond conventional precipitation reactions of electrolytes is of greater importance for gaining insights into the driving forces behind spontaneous spatiotemporal pattern formation in living matter. The Liesegang phenomenon is considered to be one of the important models for understanding well-defined periodic patterns. In this study, we have used biomolecule-derived photoluminescent carbon nanodots as reducing agents that were embedded in thin polymer films. The poor water content of polyvinyl alcohol/polyvinyl pyrrolidone films has been found to dictate the temporal scale of reaction-diffusion kinetics. Moreover, the precursors for the synthesis of nanodots have been varied to decipher the role of thiol groups present in glutathione in micron-spaced pattern formation of silver nanoparticles. A method to develop periodic patterns of plasmonic silver nanoparticles is of significant interest from technological aspects. Moreover, the formation of a micron-spaced pattern has been rationed by invoking a lowered nucleation threshold in terms of slow reaction-controlled aggregation. We expect that such an understanding of the chemical reaction-based pattern formation will help in resolving the formation of artistic spatiotemporal patterns in nature.