Graphene/cellulose nanocrystals hybrid aerogel with tunable mechanical strength and hydrophilicity fabricated by ambient pressure drying technique

Ultralight graphene/cellulose nanocrystal (CNC) hybrid aerogels (GCHAs) were prepared via an integration strategy of a two-step reduction process and ambient drying technology. Such a preparation strategy causes the as-prepared GCHAs to circumvent an issue of structural collapse induced by shrinkage in an ordinary ambient drying process. GCHAs have three-dimensional large cellular structures with CNC-sandwiched graphene flakes. Incorporation of stiff rod-like CNCs in a flexible graphene aerogel (GA) with hydrophobicity realized the multifunction of hybrid GA materials. With the increase of CNCs loading, the modulus of GCHAs enhanced obviously. The mechanical strength of GCHAs could be controlled by adjusting the CNC loading. The sorption experiments of both organic solvents and water on the GCHAs were carried out and GCHAs presented good amphiphilic absorption capacity. The work provides a promising amphiphilic graphene-based aerogel material with tunable mechanical strength by a facile, economic and environmentally-friendly approach, giving it high potential for use in waste water treatment and pressure sensitive materials.