Smart Golden Leaves Fabricated by Integrating Au Nanoparticles and Cellulose Nanofibers

摘要： A simple processing technology based on spontaneous arrangement of gold nanoparticles (AuNPs) on cellulose nanofibers (CNFs) makes it possible to form a gold leaf with superior mechanical, chemical and electrical characteristics with a small amount of gold (< 15 vol.%). The electrical resistivity of the AuNP/CNF hybrid film reached 8.7 × 10?? Ω cm at 13 vol.% corresponding to that of a gold plate (2.9 × 10?? Ω cm) through a distribution of AuNP inside the film in the form of a band. The AuNPs work not only as linkers between various CNFs in the hybrid structure but also as scaffolds. Self-assembly allows the formation of leaves on three-dimensional micrometer-sized substrates, on which it is impossible to form a uniform flexible metallic layer using conventional techniques such as sputtering, vapor deposition, and electroless plating. The hybrid film holds great promise as a novel gold leaf for a wide range of applications, including coatings, smart papers, electronic skins, and wearable devices owing to its unique combination of superior properties, as well as good productivity, processability, and renewability.