Interfacial complexation of nanocellulose based filament and its potential applications

In nature, diverse materials, such as bone, wood, and mollusk shells, are constructed by the assembly of micro- and/or nanoscopic biological building blocks into hierarchical structures. Inspired by these designs in nature, the conversion of bio-based colloidal nanoparticles into nanocomposites with pre-designed structure is attracting more and more attention. Of particular recent interest are continuous natural fibers and filaments, such as spider silk and the microfibrils in plant cells. Nanocellulose (NC), as one of the most promising biosourced nanomaterials, has become an appealing building block for the fabrication of green materials due to its abundance, biocompatibility, and tailorable surface chemistry and morphology.

In the current thesis, the fabrication of NC-based nano-structured filaments via a simple and green interfacial nanoparticle complexation (INC) method was introduced. Moreover, the feasibility of filament formation via the INC method using different oppositely charged nanoparticle pairs was demonstrated, including oppositely charged NCs, cationic chitin nanocrystals with anionic NC, and cationic NC combined with graphene oxide. Furthermore, different functional NC-based filaments were synthesized by incorporating different additives, including an antitumor drug (doxorubicin hydrochloride, DOX), silver nanoparticles (Ag NPs), and carbon nanotubes (CNTs) into NC-based filaments during the INC process. The filaments demonstrated potential applications in drug delivery, antimicrobial materials, and electronics. The developed INC method may not only provide new pathways for engineering continuous filaments from other oppositely charged nanoparticle pairs (such as DNA and protein nanofibrils) but pave the way towards a completely new class of green materials (fibers, capsules, and membranes) based on oppositely charged colloidal nanoparticles.