Emerging directions in green nanomaterials: Synthesis, physicochemical properties and applications

Abstract

Green nanomaterials, a combined outcome of the synergy of green nanotechnology and green chemistry have unique structure-based properties and eco-friendliness, and thus have been the recent focus of research and application. This article reviews the current status, barriers, and emerging developments in green nanotechnology. Initially, the analysis and categorization of prevalent synthesis strategies for green nanomaterials are undertaken, especially for techniques employing natural or nature-inspired processes. Next, recent research findings concerning the physicochemical properties of these materials are elucidated. The characteristics such as localized surface plasmon resonance (LSPR), porosity, biocompatibility, sustainability, etc. are discussed while elaborating on the phenomenon of precursor's functional group preservation. For synthesis, most of the works either have utilized biomass, natural precursors, bio-reducing agents, and bio-compatible scaffolds or have mimicked nature via self-assembly of supramolecular structures. The resulting, precisely controlled properties of such green nanomaterials provide effective solutions to many existing problems in biomedical, environmental, optoelectronics, chemical detection, etc. Consequently, classification and discussion of important applications of green nanomaterials are carried out while emphasizing their unique structure-property-application triad. Finally, future research directions are forecasted based on emerging trends in research and industrial applications. Detailed graphical foresight in the form of timelines and infographics is included to aid in the visualization of the future trajectories and transformative capabilities of green nanomaterials. The review is concluded with a relevant discourse on existing challenges and an emphasis on the ethical and conscientious utilization of green nanomaterials.