Rearrangement of Cellulose Molecular Chains in Situ for Stabilizing Two-Dimensional Nanochannels

Abstract

Two-dimensional (2D) nanochannels originating from ordered stacking of nanosheets exhibit great potential in osmotic energy harvest, which provides a promising way to address the increasing energy crisis. Although polymer nanorods have unique advantages in constructing and adjusting 2D nanochannels, the stability of these nanochannels still faces great challenges. Herein, cellulose nanocrystal (CNC) nanorods are intercalated between graphene oxide (GO) nanosheets to construct 2D sub-nanochannels. Ordered sub-nanochannel structures are first formed through a vacuum assisted self-assembly of CNC and GO. A facile strategy involving the rearrangement of cellulose molecular chains in situ is subsequently employed to stabilize the dimensions and arrangement of the sub-nanochannels. After the rearrangement, the mechanical properties and water stability of the sample are greatly enhanced due to the increased dynamic hydrogen bond network, and tensile strength and strain at break are increased by 88.7% and 472.2%, respectively. Additionally, the prepared membrane exhibits a power density of 0.74 W m-2 under a 50-fold salinity gradient and the photo-thermal conversion performance of the membrane can also benefit its osmotic power generation. Our work opens new insights into stabilizing the dimensions and arrangement of 2D nanochannels constructed by nanorods and nanosheets for commercial osmotic power generation.

Keywords: Cellulose chains rearrangement, 2D nanochannels, Ion selective membrane, Photo-thermal conversion, Osmotic power generation