Chaotic Direct Ink Writing (ChDIW) of Hybrid Hydrogels: Implication for Fabrication of Micro-ordered Multifunctional Cryogels.

The modern era demands multifunctional materials to support advanced technologies and tackle complex environmental issues caused by these innovations. Consequently, material hybridization has garnered significant attention as a strategy to design materials with prescribed multifunctional properties. Drawing inspiration from nature, a multi-scale material design approach is proposed to produce 3D-shaped hybrid materials by combining chaotic flows with direct ink writing (ChDIW). This approach enables the formation of predictable multilayered filaments with tunable microscale internal architectures using just a single printhead. By assigning different nanomaterials to each layer, 3D-printed hydrogels and cryogels with diverse functionalities, such as electrical conductivity and magnetism are successfully produced. Furthermore, control over the microscale pore morphology within each cryogel filament is achieved, resulting in a side-by-side dual-pore network sharing a large interfacial area. The ChDIW is compatible with different types of hydrogels as long as the rheological features of the printing materials are well-regulated. To showcase the potential of these multilayered cryogels, their electromagnetic interference shielding performance is evaluated, and they reveal an absorption-dominant mechanism with an excellent absorption coefficient of 0.71. This work opens new avenues in soft matter and cryogel engineering, demonstrating how simplicity can generate complexity.