All-Cellulose Paper with High Optical Transmittance and Haze Fabricated via Electrophoretic Deposition

Reducing the thickness of transparent paper without losing its outstanding optical haze and transmittance remains a challenge due to their trade-off relationship. Herein, an all-cellulose transparent paper composed of cellulose nanofibril (CNF) and carboxymethyl cellulose (CMC) is developed by electrophoretic deposition (EPD) thanks to the good film-forming ability of the CMC. The thickness of the paper can be controlled in the range of 2.4-30 μm depending on the applied voltage and deposition time. The optical properties and mechanical strength are adjusted by the sonication time and the ratio between CNF and CMC, since the CNF works as a light-scattering source and mechanical reinforcement agent. Consequently, a robust all-cellulose paper with a thickness of 10 μm exhibiting high transmittance (up to 96%) and haze (up to 89%) is successfully fabricated. As our paper has competitive optical properties despite the thinner thickness than other reported all-cellulose transparent and hazy paper, we achieved the highest optical haze and transmittance values per unit thickness. We believe that this all-cellulose paper with outstanding optical properties has great potential to be applied to many fields that include flexible devices, environmentally friendly electronics, optoelectronics, and other functional devices.