Eucalyptus bleached kraft pulp-ionic liquid inks for 3D printing of ionogels and hydrogels

3D printing has been recently recognized as one of the most promising technologies due to the multiple options to fabricate cost-effective and customizable objects. However, the necessity to substitute fossil fuels as raw materials is increasing the research on bio-based inks with recyclable and eco-friendly properties. In this work, we formulated inks for the 3D printing of ionogels and hydrogels with bleached kraft pulp dissolved in [Emim] [DMP] at different concentrations (1-4 wt%). We explored each ink's rheological properties and printability and compared the printability parameters with a commercial ink. The rheological results showed that the 3 % and 4 % cellulose-ionic liquid inks exhibited the best properties. Both had values of damping factor between 0.4 and 0.7 and values of yield stress between 1900 and 2500 Pa. Analyzing the printability, the 4 wt% ink was selected as the most promising because the printed ionogels and the hydrogels had the best print resolution and fidelity, similar to the reference ink. After printing, ionogels and hydrogels had values of the elastic modulus (G ') between 103 and 104 Pa, and the ionogels are recyclables. Altogether, these 3D printed cellulose ionogels and hydrogels may have an opportunity in the electrochemical and medical fields, respectively.

Automated summary

3D printing is a promising technology for fabricating cost-effective and customizable objects. Research on bio-based inks with recyclable and eco-friendly properties is increasing due to the need to substitute fossil fuels as raw materials. In this study, ionogels and hydrogels were formulated for 3D printing using cellulose dissolved in [Emim] [DMP] at different concentrations. Rheological properties and printability were compared with a commercial ink, and the 4 wt% ink was found to have the best print resolution and fidelity. These 3D printed cellulose ionogels and hydrogels may have applications in the electrochemical and medical fields, respectively.