Covalent Bond Interfacial Recognition of Polysaccharides/Silica Reinforced High Internal Phase Pickering Emulsions for 3D Printing

Abstract

Significant challenges remain in designing sufficient viscoelasticity polysaccharide-based high internal phase Pickering emulsions (HIPPEs) as soft materials for 3D printing. Herein, taking advantage of the interfacial covalent bond interaction between modified alginate (Ugi-OA) dissolved in the aqueous phase and aminated silica nanoparticles (ASNs) dispersed in oil, HIPPEs with printability were obtained. Using multitechniques coupling a conventional rheometer with a quartz crystal microbalance with dissipation monitoring, the correlation between interfacial recognition coassembly on the molecular scale and the stability of whole bulk HIPPEs on the macroscopic scale can be clarified. The results showed that Ugi-OA/ASNs assemblies (NPSs) were strongly retargeted into the oil−water interface due to the specific Schiff base-binding between ASNs and Ugi-OA, further forming thicker and more rigid interfacial films on the microscopic scale compared with that of the Ugi-OA/SNs (bared silica nanoparticles) system. Meanwhile, flexible polysaccharides also formed a 3D network that suppressed the motion of the droplets and particles in the continuous phase, endowing the emulsion with appropriately viscoelasticity to manufacture a sophisticated "snowflake" architecture. In addition, this study opens a novel pathway for the construction of structured all-liquid systems by introducing an interfacial covalent recognition-mediated coassembly strategy, showing promising applications.

Ultrastable High Internal Phase Pickering Emulsions: Forming Mechanism, Processability, and Application in 3D Printing

“…The well-controlled rheological property is the first requirement for the suitable 3D printing inks . The PPH NP-stabilized HIPPEs exhibited shear-thinning behavior, which is promising for application in 3D printing . Therefore, the circle-, square-, and moon-shaped 3D objects were created via an extrusion-based technique from the HIPPEs with 80% oil fraction without spreading due to their solid viscoelastic gel texture.…”