Smart materials in water governance: Pollution remediation, resource acquisition, and energy harvest

As global water scarcity and security challenges intensify, traditional water treatment materials struggle to meet practical demands due to their limited efficiency and single-functionality. Smart materials—particularly those with stimulus-responsive and adaptive properties—have emerged as promising alternatives, thanks to their dynamic functional regulation, environmental adaptability, and multifunctional integration capabilities. This review systematically examines the principles of smart materials from micro to macro scales, covering environmental sensing and output mechanisms, including pH, temperature, light, and magnetic responses, as well as self-cleaning and self-healing functions. It critically compares their performance in pollution remediation, resource recovery, and energy capture. The study highlights inherent limitations in current materials, such as reduced responsiveness in complex aquatic environments, insufficient long-term stability, functional conflicts, and scalability challenges. Furthermore, it explores forward-looking strategies to address these issues, including orthogonal multi-stimulus response design, performance validation under real-world conditions, environmentally friendly material alternatives, and integration with real-time sensing and artificial intelligence technologies. By evaluating material performance and summarizing future development directions, this review provides a systematic theoretical framework and practical guidance for developing next-generation smart water treatment systems that prioritize sustainable water security, resource recycling, and energy synergy. This review summarizes the mechanisms and applications of smart materials used in water treatment, resource acquisition, and energy harvesting. It generally discusses stimulus-responsive materials and self-adaptive materials, as well as the challenges and prospects of designing multifunctional, intelligence-integrated smart materials. • Rising global water scarcity and safety concerns require innovative solutions. • Self-adaptive and responsive materials exhibit smart potentials for water treatment. • Intelligent materials achieve flexibility and durability in different scenarios. • Modular, sequential, and innovative design forms one comprehensive platform. • Challenges and prospects in the materials’ design and applications are discussed.