Metal Coordination Bonds Crosslinked Polydopamine/Cellulose Nanofibril Composite Aerogels with Significantly Improved Thermal Stability, Flame Resistance, and Thermal Insulation Properties

Cellulose nanofibril (CNF) aerogels have attracted great interests in recent years due to the low cost, sustainability and biocompatibility of raw CNFs. However, the poor thermal stability and flammable feature of CNF aerogels have limited their wider applications. In this paper, polydopamine/CNF composite aerogels with good comprehensive properties are fabricated by modification of CNF with polydopamine and metal coordination bonds crosslinking. The microstructure and properties of composite aerogels are thoroughly characterized by a variety of tests. It is found that the microstructure of aerogels are more regular and the compressive strength of aerogels are enhanced by the incorporation of polydopamine and Fe3+ crosslinking. Importantly, the thermal stability and flame resistance of aerogels are significantly improved, which permit the application of composite aerogels in high-temperature thermal insulation. In addition, the reversible characteristic of metal coordination bonds allows the water induced healing of fractured composite aerogels. This study is expected to provide information for future development of green and high-performance aerogels.