1. Anisotropic nanocellulose aerogels with ordered structures fabricated by directional freeze-drying for fast liquid transport.
- Author
-
Chen, Yiming, Zhou, Lijie, Chen, Lian, Duan, Gaigai, Mei, Changtong, Huang, Chaobo, Han, Jingquan, and Jiang, Shaohua
- Subjects
AEROGELS ,FREEZE-drying ,TEMPERATURE effect ,CELLULOSE - Abstract
Directional freeze-drying is considered to regulate the structure of nanocellulose aerogels with special performances. In this work, TEMPO-oxidized cellulose nanofiber aerogels with high porosity (> 99.5%) and low density (~ 7 mg/cm
3 ) were produced by different freeze-drying methods. The effects of temperature, freezing reagents and freezing methods on the structure and properties of aerogels were investigated. Among them, an anisotropic cellulose aerogel was obtained using a simple and flexible directional freezing in ethanol of − 30 °C by a self-made directional freezer. Our results demonstrated that it could present honeycomb-like pores in the transverse direction and regular directional tunnels in the longitudinal direction, and some attractive features, such as high water adsorption (120 g/g) and stability in water. Compared with other aerogels, this anisotropic structure also provided the aerogel with excellent compressive property (15.2 kPa) and faster liquid transport (4.95 mm/s) in the longitudinal direction than in other directions. The distinctive aerogels based on nanocellulose by directional freeze-drying are also expected to be combined with multifunctional materials to achieve directional applications to meet the requirements of different fields. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF