title: Recent advances in clay mineral-containing nanocomposite hydrogels.
abstract: Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.
authors.affiliation: Research Group for Advanced Materials & Sustainable Catalysis (AMSC), Institute of Advanced Catalytic Materials, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China. clay@zjut.edu.cn chc.zhou@aliyun.com.
authors.forename: Li Zhi
authors.initials: LZ
authors.lastname: Zhao
authors.affiliation: Research Group for Advanced Materials & Sustainable Catalysis (AMSC), Institute of Advanced Catalytic Materials, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China. clay@zjut.edu.cn chc.zhou@aliyun.com and Key Laboratory of Clay Minerals of Ministry of Land and Resources of The People's Republic of China, Engineering Research Center of Non-metallic Minerals of Zhejiang Province, Zhejiang Institute of Geology and Mineral Resource, Hangzhou 310007, China.
authors.forename: Chun Hui
authors.initials: CH
authors.lastname: Zhou
authors.affiliation: Centre of Excellence in Engineered Fibre Composites, University of Southern Queensland, Toowoomba, Queensland 4350, Australia. Chun.Zhou@usq.edu.au.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Research Group for Advanced Materials & Sustainable Catalysis (AMSC), Institute of Advanced Catalytic Materials, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China. clay@zjut.edu.cn chc.zhou@aliyun.com.
authors.forename: Dong Shen
authors.initials: DS
authors.lastname: Tong
authors.affiliation: Research Group for Advanced Materials & Sustainable Catalysis (AMSC), Institute of Advanced Catalytic Materials, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China. clay@zjut.edu.cn chc.zhou@aliyun.com.
authors.forename: Wei Hua
authors.initials: WH
authors.lastname: Yu
authors.affiliation: Centre of Excellence in Engineered Fibre Composites, University of Southern Queensland, Toowoomba, Queensland 4350, Australia. Chun.Zhou@usq.edu.au.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang