PrefaceIonic liquids have emerged as one of the most important classes of materials in modern chemistry and materials science. Unlike conventional molecular solvents, ionic liquids consist entirely of ions and often remain liquid near room temperature. Their negligible vapor pressure, excellent thermal and electrochemical stability, broad liquid temperature range, high solvating ability, and highly tunable physicochemical properties have made them enabling materials for sustainable technologies, advanced manufacturing, energy storage, catalysis, separations, biotechnology, and environmental engineering. During the past three decades, ionic liquids have evolved from laboratory curiosities into versatile functional materials with growing academic and industrial significance.This book provides a comprehensive, interdisciplinary, and practical introduction to ionic liquid science and technology. It bridges the gap between fundamental chemistry and modern applications by integrating theoretical principles with current research and engineering practice. The text is intended for graduate students, researchers, educators, and professionals in chemistry, chemical engineering, materials science, electrochemistry, nanotechnology, biotechnology, pharmaceutical sciences, and related fields.The book begins with the history, molecular structures, synthesis methods, nomenclature, classification, and physicochemical properties of ionic liquids. Subsequent chapters discuss thermodynamics, transport properties, spectroscopy, computational modeling, toxicity, environmental considerations, and safety. Particular emphasis is placed on understanding how cation–anion combinations and molecular design influence viscosity, conductivity, thermal stability, electrochemical behavior, and application-specific performance, providing a foundation for the rational design of task-specific ionic liquids.A major focus of this volume is the expanding role of ionic liquids in emerging technologies. Applications covered include catalysis, organic synthesis, biomass processing, carbon capture, gas separations, batteries, supercapacitors, fuel cells, hydrogen technologies, lubricants, heat-transfer fluids, pharmaceuticals, drug delivery, biotechnology, analytical chemistry, nanomaterials, and advanced manufacturing. Recent developments involving deep eutectic solvents, bio-based ionic liquids, artificial intelligence, machine learning, and computational materials discovery are also introduced to illustrate future directions in the field.Throughout the book, complex concepts are explained using clear discussions supported by carefully prepared figures, tables, practical examples, and engineering perspectives. Recent scientific literature has been incorporated wherever appropriate to provide readers with an up-to-date understanding of both established knowledge and rapidly evolving research areas. Although every effort has been made to ensure scientific accuracy, ionic liquid research continues to advance rapidly, and readers are encouraged to consult current literature for the latest developments.The remarkable versatility of ionic liquids demonstrates how advances in molecular design can transform multiple scientific disciplines while supporting cleaner manufacturing, sustainable energy systems, and environmentally responsible chemical processes. It is my sincere hope that this book will serve as a valuable resource for education, research, and industrial innovation, while inspiring future scientists and engineers to explore the exciting opportunities that ionic liquids offer for solving important scientific and technological challenges.
