Conductive hydrogels combining the electrical properties of conductive materials such as metallic nanoparticles, conductive polymers, or carbon-based materials with features such as high water-content and tuneable physical and chemical properties have become promising candidates for developing printable inks for biomedical and electronics industries. Nanocellulose (NC) is the primary building block of plants and gained significant attention as an additive in inks. NC displays time-dependent shear-thinning behaviour, assisting the extrusion process and ink deposition, essential for developing intricate patterns and structures with micrometre precision. In addition, the versatile surface chemistry of NC enables stabilisation and synthesis of conductive materials such as metallic nanoparticles, supporting the ink formulation.<br/> <br/>We aim to develop an NC-based polymer brush system as a template to direct the synthesis of gold metallic nanoparticles and avoid the agglomeration of gold nanoparticle in the hydrogel. By tuning the polymer brush density and polymer length, ink's conductivity and rheological properties can be fine-tuned to obtain specific characteristics. In the first step, we developed a systematic procedure to control cellulose nanocrystal functionalisation to convert the OH-groups on the surface to an ATRP initiating group by varying the reaction conditions. This tunability on the degree of substitution (DS) on NC has not been described in literature before. FTIR, TGA, and solid-state NMR were performed to assess the substitution degrees' variation on the NC surface while optimising reaction conditions to maintain the rod-like morphology. This step will control the polymer brush density and metal nanoparticle morphology, determining the final composite properties.

Nanocellulose-based conductive polymer brush materials

ACS Spring Meeting 2021

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