Multiscale cellulose-based optical management films with tunable transparency and haze fabricated by different bamboo components and mechanical defibrillation approaches

Renewable cellulose is an outstanding candidate to prepare biomass-based optical management films with tunable transparency and haze. Micro-scale and nano-scale cellulose derived from the parenchyma cells (PC) and bamboo fibers (BF) of Dendrocalamus sinicus was first separated and then subjected to succinic esterification and mechanical defibrillation using three different methods: ultrasonication, high-speed blending, and microfluidization. Sustainable multiscale optical management films with tunable haze were obtained by changing the weight ratios of micro/nanoscale cellulose. The PC-based micro/nano cellulose (MNC) films obtained by microfluidization with the highest content of nanoscale cellulose (96.5 %) displayed the highest light transmittance (89.4 %) and tensile strength (164.3 MPa) but the lowest haze (32.0 %) and anti-glare ability. The BF-based MNC films obtained by ultrasonication with the lowest content of nanoscale cellulose (20.4 %) but the highest content of microscale cellulose (79.6 %) showed the highest haze (96.7 %), a medium light transmittance (81.3 %), and the outstanding anti-glare effects. The MNC films with both high in transparency (84.8–87.5 %) and haze (81.5–88.4 %) along with good strength and flexibility can be obtained by tuning the bamboo components and mechanical defibrillation methods. This study provides a green and facile way to fabricate sustainable optical management films.