Highly transparent and flexible silica/cellulose films with a low coefficient of thermal expansion

Abstract

Highly transparent and flexible silica/cellulose films with low thermal expansion coefficients have been prepared by the in situ synthesis of silica in cellulose scaffolds using Na₂SiO₃ as a precursor. The low content of silica in the composite films had an influence on the tensile strength of the composites. Furthermore, the composite films integrated the merits of cellulose and silica. The transmittance of the composite films in the visible light region were comparable to that of glass, but the films were foldable. Moreover, the composite films had CTEs lower than 15 ppm K⁻¹. The composite films would be the perfect substrates for the future production of electronic devices, such as flexible displays and e-papers, and could replace costly conventional batch processes based on the glass substrates currently used, and eventually be applied to rollable and even foldable devices.