Design of Advanced Filaments from Cellulose Nanofibrils Using a Coaxial Spinning Strategy

The use of flow-focusing for the preparation of filaments from Cellulose I fibrils has allowed for the preparation of ultrastrong, continuous fibres with excellent wet-strength (1). By applying careful hydrodynamic alignment of the fibrils in combination with a colloidal control and locking of the oriented state it is possible to, almost, fully utilize the excellent inherent properties of the CNFs (Cellulose Nano Fibrils). It has also been shown that it is possible to use a simpler, coaxial set-up to prepare oriented filaments where the coaxial alignment also allows for the preparation of interactive filaments using a combination of CNFs and for example Carbon Nano Tubes (CNTs) (2). In this work (2) a core-shell structure was produced where the active components were assembled in a thin layer outside a core of CNFs. In the present work the coaxial spinning strategy has been further expanded by using a coaxial spinning equipment with three channels allowing for the preparation of even more advanced structures. With this set-up it has been possible to prepare filaments containing an external thin layer of high-quality CNFs encapsulating core materials with dimensions from the nano-scale to the macroscale. In this way is has been possible to form filaments containing gases, conductive polymers, nanoparticles and macroscopic fibres modified to meet certain end-use properties. The details behind the preparation of the filaments and the final filaments properties will be discussed.<br/>1. Mittal, N., Ansari, F., Gowda Krishne, V., Brouzet, C., Chen, P., Larsson, P. T., Roth, S.V., Lundell, F., Wågberg, L. and Söderberg, L. D. (2018). Multiscale Control of Nanocellulose Assembly: Transferring Remarkable Nanoscale Fibril Mechanics to Macroscale Fibers. <i>ACS Nano</i>, <i>12</i>(7), 6378–6388.<br/>2. Marais, A., Wågberg, L., Erlandsson, J., and Söderberg, L. (2020). Coaxial spinning of oriented nanocellulose filaments and core− Shell structures for interactive materials and fiber-reinforced composites. <i>ACS Applied Nano Materials</i>, <i>3</i>(10), 10246–10251.