Supramolecular assemblies constructed from muscovite nanosheets and cellulose nanofibrils: Enhancing mechanical energy dissipation of polymers.

To further improve the lubrication ability of flexible polyvinyl alcohol (PVA) composite films under dry friction and make it be used to encapsulate and protect irregularly shaped equipment. Herein, the friction and adhesion of nanocellulose (NC) and sodium carboxymethylcellulose (CMC) on the surface of muscovite (Mica) were used to achieve in-situ exfoliation of large-size Mica nanosheets. The construction of NC/CMC/Mica supramolecular assembly systems was formed via complex intermolecular hydrogen bonds and electrostatic attraction. The PVA composites modified with NC/CMC/Mica exhibited excellent thermal stability, mechanical strength, superior flexibility, and self-lubricating properties. The supramolecular architecture of rigid Mica nanosheets and flexible NC framework enhances the comprehensive performance of polymers to achieve stronger intermolecular cross-linking. Thus, the entanglement of nanofibrils, hydrogen bonding interaction between NC/CMC/Mica, and the chemical reaction between NC and PVA molecular chains under the crosslinking of epichlorohydrin give the NCMP films excellent tensile strength (188.15 MPa), toughness (82.08 MJ/m), and self-lubricating ability. The mechanical and self-lubricating properties of composite films were described from the level of macro-phenomena to micro-mechanisms, thus proposing the self-enhancement and lubrication mechanisms.