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Shape memory materials (SMMs) in 3D printing (3DP) technology garnered much attention due to their ability to respond to external stimuli, which direct this technology toward an emerging area of research, “4D printing (4DP) technology.” In contrast to classical 3D printed objects, the fourth dimension, time, allows printed objects to undergo significant changes in shape, size, or color when subjected to external stimuli. Highly precise and calibrated 4D materials, which can perform together to achieve robust 4D objects, are in great demand in various fields such as military applications, space suits, robotic systems, apparel, healthcare, sports, etc. This review, for the first time, to the best of the authors’ knowledge, focuses on recent advances in SMMs (e.g., polymers, metals, etc.) based wearable smart textiles and fashion goods. This review integrates the basic overview of 3DP technology, fabrication methods, the transition of 3DP to 4DP, the chemistry behind the fundamental working principles of 4D printed objects, materials selection for smart textiles and fashion goods. The central part summarizes the effect of major external stimuli on 4D textile materials followed by the major applications. Lastly, prospects and challenges are discussed, so that future researchers can continue the progress of this technology.

Quantum dots (QDs) exhibit unique physicochemical and optical properties that are suitable for photovoltaic cells, light-emitting diodes, and optoelectronic devices; however, unlike selenium and tellurium/metalsulfide-based QDs, graphene quantum dots (GQDs) are comparatively less toxic and biocompatible, making them promising candidates for biological applications such as bioimaging, drug delivery agents, therapeutics, and theranostics. Various synthesis techniques such as top-down and bottom-up methods along with novel green synthesis methods for the preparation of pure and doped GQDs are thoroughly discussed in this study. Physicochemical, optical, and biological properties such as size-and chemical-compositiondependent fluorescence, therapeutics, disease diagnostics, biocompatibility, and cellular toxicity are extensively studied and summarized. Finally, the prospects and potential directions of GQDs in drug delivery and bioimaging systems are discussed in regards to challenges such as the synthesis, biocompatibility, and cellular toxicity.

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Dye containing industrial effluent streams are a cause of major environmental concerns, especially those which are not easily biodegradable. Many techniques have been developed to remove dyes from the waste stream; however, most of them suffer from a weakness of efficiency and effectiveness when an attempt is made for industrial implementation. A recently developed dye removal method using surfactants offers the benefits of high removal efficiency, ease of waste disposal, scope of efficient recovery, and the use of nontoxic and less harmful reagents. This review aims to contribute to this growing area by summarizing the mechanisms of dye−surfactant interactions and investigating the influence of different process parameters such as pH, concentration of surfactants, dyes, and electrolytes, temperature, etc. on the efficiency of the method. The review also attempts to present future research scopes of these techniques with a critical analysis of industrial applicability.

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