Micro- and nano-fibrils of manau rattan and solvent-exchange-induced high-haze transparent holocellulose nanofibril film

Holocellulose nanofibrils (HCNFs) are nanoscale objects extracted from biomass resources and have attracted attention as sustainable building blocks for nanomaterials. In this study, we report a top-down approach for extracting HCNFs from manau rattan that involves pulping, bleaching and TEMPO oxidation. The extracted HCNFs showed a uniform width of around 18.5 nm and a length of a few micrometers, high crystallinity (66.5 %), and good thermal stability (302 °C). The extracted HCNFs were used to fabricate HCNF film via vacuum filtration and drying (air drying and solvent exchange drying). Surprisingly, the HCNF film fabricated by solvent exchange drying (HCNF-filmSD) simultaneously presented a high total transmittance (93.7 %) and high haze (62.2 %), and its total transmittance was even higher than that of glass. The resulting HCNF-filmSD displayed a high tensile strength (84.8 MPa), Young's modulus (3.7 GPa), and toughness (1.4 MJ m−3), making it a high-performance and eco-friendly film for applications in precision optoelectronics and aerospace materials.