Yang Weisheng, Jiao Liang, Liu Wei, Dai Hongqi
Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forestry Resources, Nanjing Forestry University, Nanjing 210037, Jiangsu, China.
School of Chemical & Biomolecular Engineering and Renewable Bioproducts Institute, Georgia Institute of Technology, Atlanta, GA 30318, USA.
Nanomaterials (Basel). 2019 Jan 16;9(1):107. doi: 10.3390/nano9010107.
Traditionally, inorganic nanoparticles (SiO₂, TiO₂) have been utilized to tune the optical haze of optoelectronic devices. However, restricted to complex and costly processes for incorporating these nanoparticles, a simple and low-cost approach becomes particularly important. In this work, a simple, effective, and low-cost method was proposed to improve optical haze of transparent cellulose nanofibril films by directly depositing micro-sized 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized wood fibers ("coating" method). The obtained films had a high total transmittance of 85% and a high haze of 62%. The film samples also showed a high tensile strength of 80 MPa and excellent thermal stability. Dual sides of the obtained films had different microstructures: one side was extremely smooth (root-mean-square roughness of 6.25 nm), and the other was extremely rough (root-mean-square roughness of 918 nm). As a reference, micro-sized TEMPO-oxidized wood fibers and cellulose nanofibrils were mixed to form a transparent and hazy film ("blending" method). These results show that hazy transparent films prepared using the "coating" method exhibit superior application performances than films prepared using the "blending" method.
传统上，无机纳米粒子（二氧化硅、二氧化钛）已被用于调节光电器件的光学雾度。然而，由于掺入这些纳米粒子的工艺复杂且成本高昂，一种简单且低成本的方法变得尤为重要。在这项工作中，提出了一种简单、有效且低成本的方法，通过直接沉积微米尺寸的2,2,6,6-四甲基哌啶-1-氧基（TEMPO）氧化木纤维（“涂布”法）来提高透明纤维素纳米纤丝薄膜的光学雾度。所得薄膜具有85%的高总透光率和62%的高雾度。薄膜样品还表现出80MPa的高拉伸强度和优异的热稳定性。所得薄膜的两面具有不同的微观结构：一面极其光滑（均方根粗糙度为6.25nm），另一面极其粗糙（均方根粗糙度为918nm）。作为参考，将微米尺寸的TEMPO氧化木纤维和纤维素纳米纤丝混合以形成透明且有雾度的薄膜（“共混”法）。这些结果表明，使用“涂布”法制备的有雾度的透明薄膜比使用“共混”法制备的薄膜表现出更优异的应用性能。
