Anisotropic, nanoporous structures are promising materials for manipulating the propagation of electromagnetic waves at millimeter and sub-THz frequencies as well as for electromagnetic interference (EMI) shielding with rapidly evolving green electronics. In this work, cell and surface architecture of sustainable hybrid cryogels of cellulose nanofibers, polyvinyl alcohol (PVA) and Ti₃C₂T_X MXene was controlled to adjust their GHz and THz dielectric permittivity and EMI shielding performance. Temperature gradient freeze-drying was used to obtain aligned honeycomb and lamellar pore structures with specific surface layer designs. The millimeter wave permittivity varied relative to thickness direction as the side of cryogels that was directly exposed to cold gradient had systematically a higher permittivity. This anisotropy was caused by a thin, smooth outermost surface layer covering the open core structure. The surface designs of all cryogels dominated signal permittivity, and the effects of higher MXene dosages could be offset by the surface layer. Cryogels with dense surface layer containing 70 and 50 wt % of MXene displayed very high average attenuation levels of 52.1 and 37.2 dB, respectively. Overall, the results show that the structural design of porous hybrid material can be used to adjust their EMI shielding performance at GHz and THz frequencies.

各向异性纳米多孔结构是很有前途的材料，可用于控制毫米和亚太赫兹频率的电磁波传播，以及用于快速发展的绿色电子产品的电磁干扰 (EMI) 屏蔽。在这项工作中，纤维素纳米纤维、聚乙烯醇 (PVA) 和 Ti ₃ C ₂ T _{X的可持续混合冷冻凝胶的细胞和表面结构}控制 MXene 以调整其 GHz 和 THz 介电常数和 EMI 屏蔽性能。温度梯度冷冻干燥用于获得具有特定表面层设计的对齐蜂窝和层状孔结构。毫米波介电常数相对于厚度方向变化，因为直接暴露于冷梯度的冷冻凝胶的一侧系统地具有更高的介电常数。这种各向异性是由覆盖在开放核心结构上的薄而光滑的最外表面层引起的。所有冷冻凝胶的表面设计都主导着信号介电常数，而较高 MXene 剂量的影响可能会被表面层抵消。含有 70 和 50 wt% MXene 的致密表面层的冷冻凝胶显示出非常高的平均衰减水平，分别为 52.1 和 37.2 dB。全面的，