Highly transparent and hazy paper with desirable characteristics for flexible electronic devices

Exploring functional paper-based materials in advanced electronics meets the requirements of high-value utilization of biological resources and sustainable development. Herein, a facile strategy of impregnating cellulose-based polyurethane into cellulose paper was developed to fabricate highly transparent paper with desirable requirements. The novelty of this work lies in the development of a sustainable technology to prepare highly transparent and hazy paper, which uses a facile impregnation treatment of cellulose-based polyurethane to obtain functional paper with high transparency, high optical haze, low surface roughness, hydrophobicity, excellent tensile strength, water barrier property, and shape memory behavior. The desirable characteristics were attributed to the tight combination of cellulose paper and cellulose-based polyurethane based on covalent and hydrogen bonds. The desirable properties of highly transparent paper included high optical transmittance (84.1% at 800 nm), high optical haze (92.6% at 800 nm), low root-mean-square roughness (0.28 nm), excellent tensile strength (37.62 MPa), hydrophobicity (water contact angle of 115.5°), water barrier property, and shape memory behavior. Especially, the transparent paper with carbon nanotubes lines has high conductivity even after bending, folding and immersing. The ideal characteristics of highly transparent and hazy paper provide vast opportunities for the development of flexible electronic devices.