Three-dimensional (3D) microfibrillar network represents an important structural design for various natural tissues and synthetic aerogels. Despite extensive efforts, achieving high mechanical properties for synthetic 3D microfibrillar networks remains challenging. Here, we report ultrastrong polymeric aerogels involving self-assembled 3D networks of aramid nanofiber composites. The interactions between the nanoscale constituents lead to assembled networks with high nodal connectivity and strong crosslinking between fibrils. As revealed by theoretical simulations of 3D networks, these features at fibrillar joints may lead to an enhancement of macroscopic mechanical properties by orders of magnitude even with a constant level of solid content. Indeed, the polymeric aerogels achieved both high specific tensile modulus of ~625.3 MPa cm³ g⁻¹ and fracture energy of ~4700 J m⁻², which are advantageous for diverse structural applications. Furthermore, their simple processing techniques allow fabrication into various functional devices, such as wearable electronics, thermal stealth, and filtration membranes. The mechanistic insights and manufacturability provided by these robust microfibrillar aerogels may create further opportunities for materials design and technological innovation.

三维（3D）微纤维网络代表了各种天然组织和合成气凝胶的重要结构设计。尽管付出了巨大的努力，实现合成 3D 微纤维网络的高机械性能仍然具有挑战性。在这里，我们报道了涉及芳纶纳米纤维复合材料自组装 3D 网络的超强聚合物气凝胶。纳米级成分之间的相互作用导致组装网络具有高节点连接性和原纤维之间的强交联。正如 3D 网络的理论模拟所揭示的那样，即使固体含量水平恒定，纤维接头处的这些特征也可能导致宏观机械性能提高几个数量级。事实上，聚合物气凝胶实现了约625.3 MPa cm ³ g ^-1的高比拉伸模量和约4700 J m ^-2的断裂能，这对于不同的结构应用是有利的。此外，它们简单的加工技术允许制造成各种功能设备，例如可穿戴电子产品、热隐形和过滤膜。这些坚固的微纤维气凝胶提供的机械见解和可制造性可能为材料设计和技术创新创造更多机会。