Next to conventional cellulose fibers and films, gels and subsequent aerogels are an emerging class of bio-based materials, where especially cellulose II aerogels are known for tunable materials properties. These cellulose II aerogels are frequently prepared from coagulation of cellulose from dilute solutions. They can show a variety of morphologies dependent on the employed solvent- and anti-solvent system, which makes them extremely versatile, applicable for e.g. cell scaffolding, filter applications or photonic materials.
In our recent study we managed to follow a novel simple and energy efficient route to obtain anisotropic cellulose II gels and subsequently aerogels from self-assembly. By light microscopy, SEM and scanning SAXS we found a radial symmetrically ordered structure determined by the gelation process. By time resolved measurements we were able to follow the structural development of the network. The controlled self-assembling of the polymer into gel-structures with controlled orientations, extending to the macroscopic scale, is driven by diffusion and mixing of the solvent and anti-solvent coinciding with coagulation.
Our new approach yields the potential of future industrial usability for bio-based materials with complex morphologies.