Silica aerogel films via ambient pressure drying for broadband reflectors. (4th April 2018)

• Record Type: Journal Article
• Authors: Wang, Xiaobo; Zhang, Yue; Luo, Jieya; Wang, Dong; Gao, Hong; Zhang, Jingjing; Xing, Yan; Yang, Zhou; Cao, Hui; He, Wanli
• Is Part Of: New journal of chemistry. Volume 42:Number 8(2018)
• Page Start: 6525
• Page End: 6531
• Publication Date: 2018-04-04
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj05159j
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : This manuscript demonstrates the advantages of silica aerogel films over nanoparticles in broadening the reflection bandwidth of cholesteric liquid crystals. Abstract : As an unusual two-dimensional porous nanomaterial, a silica aerogel film was composited with a chiral nematic liquid crystal (N*-LC) to broaden the bandwidth. Here, a thin film of silica aerogel has been synthesized via ambient drying of the wet gel film that was obtained by the sol–gel process of tetraethoxysilane (TEOS). The porosity of the silica aerogel film depends on the hydrolysis and condensation of TEOS, and the modification of the microstructure of the wet gel film. The silica aerogel film/chiral nematic liquid crystal composite films were prepared by compositing the N*-LC with two kinds of silica aerogel films with different porosities. It is found that the reflection bandwidth (Δ λ ) of the composite film increased upon increasing the porosity of the silica aerogel film. Meanwhile, combining the anchoring effect of the polymer network, Δ λ of the composite films was changed from 178 nm to 270 nm and the center wavelength was redshifted by approximately 120 nm. As a result, a presumed mechanism has been proposed to explain the effect of silica aerogel films on the N*-LC.