Differences of wax-based emulsion gel in 3D printing performance: Crystal distribution and droplet stability

Six kinds of natural waxes were used for emulsion gels preparation. The differences in printing performance were explored based on the crystal distribution and droplet stability. Firstly, the effect of crystal distribution was investigated through microstructures and rheological properties. It was found that the dense crystal network/interfacial crystallization could stabilize the droplet and provide modulus to ensure the self-supporting behavior after printing, whereas excessive crystal could lead to droplet rupture and coalescence. Furthermore, all emulsion gels could recrystallize by heating, which could enhance the performance of 3D printing. Then, the droplet stability was investigated after storing/freeze-thawing. It was found that emulsion gels with dense crystal networks/interfacial crystallization had more stable droplets, which ensure the continuous extrusion during printing. Finally, printing performance was investigated comprehensively. Three emulsion gels with denser crystal networks/interfacial crystallization had higher recovery rates (16.17-21.15%) and more stable droplets, which perform better in 3D printing correspondingly.