Green solvents tailored nanostructures of block copolymers and their potential applications in drug delivery

[Display omitted] •Significance and current state of affairs in ionic liquids (ILs), Deep Eutectic solvent (DESs), and their structure–property relationship.•Recent developments and application of ILs and DESs in drug delivery systems.•Physiological toxicity of ILs and DESs.•The significance of block copolymer nanostructures in drug delivery and the current status of their development.•Role and emergence of block copolymers and their self-assembly within ILs and DESs media and the current state of affairs. In the past decades, deep eutectic solvents (DESs) and ionic liquids (ILs) have garnered significant interest in variousdisciplines of the chemical, physical and biological sciences as task-oriented (designer)and emerging “green” solvent substitutes to the hazardous and volatile organicsolvents. The physicochemical properties of these green designer solvents are precisely customizable by tuning the structures of their constituents for a particular application. These unique substances have shown enormous application potentials in several interdisciplinary research fields, like, catalysis, synthesis, biocatalysis, separation and extraction, biomolecular dissolution and stability, nanoscience, pharmaceutics, and drug delivery. Furthermore, block copolymers (BCPs) self-assembled nanostructures such as vesicles, micelles, microemulsions, polymersomes, etc. formed within different solvent media have attracted various researchers around the world owing to their immense potential for application in several domains of science and technology including drug delivery, photonic material, data storage, etc. This review highlights current advancements in the self-assembly of BCPs forming nanostructures within green designer solvent media like ILs and DESs. Additionally, it also gives an overview of applications of ILs, DESs, and external stimuli-responsive BCP within ILs and DESs, as drug delivery vehicles. This review will further enhance the potential utility of these unique materials (so-called designer solvents) and will help researchers design novel ILs and DESs for suitable applications including polymer science, nanoscience, pharmaceutics, drug delivery, etc.