Smart cellulose-hydrogel composites for 4D printing

In nature, versatility and functionality is a consequence of controlled placement of 'building blocks' at nano and micro-scale and the resulting multifunctional hierarchical structures. This approach to manufacturing and philosophy is gaining interest among researches as it offers many advantages over traditional top down manufacturing. Latest developments in 3D printing (3DP) technology allows one to have control over the placement of building materials in 3D space. This paper focus on the development of a cellulose hydrogel composite that can be adapted for 3D printing. This system preserves the functionality of cellulose while enabling printing through a syringe extrusion system. Unlike conventional 3DP materials, this bespoke bio-inspired composite is sentient and can morph along the design rules we observe in nature such as pinecones in response to the stimuli of water. This paper presents the development and characterisation of the cellulose hydrogel composite.