Electrospinning Device for Nanofibers| Thermotropic liquid crystal-driven interfacial fusion of high-aspect-ratiopolyarylate nanofibers for ultrastable honeycomb withclosed-loop recyclability

Aramid honeycomb materials, as a typical biomimetic structure, consist of periodically arranged hexagonal units, exhibiting excellent mechanical stability, load dispersion capability, and lightweight advantages. These properties make them widely applicable in critical fields such as aerospace, military, and rail transportation. The honeycomb structure effectively reduces localized stress concentration and achieves an optimal balance between high strength and lightweight, making it an ideal material for various engineering applications.  However, traditional aramid honeycomb fabrication faces challenges such as complex processes and low production efficiency. Additionally, the small aspect ratio, low specific surface area, and high rigidity of aramid fibers limit the contact area between fibers, affecting the uniformity and density of the honeycomb structure and thereby restricting improvements in mechanical performance. Moreover, excessive reliance on adhesives can lead to defects such as interfacial debonding, double-layer walls, and nested pores, further compromising the structural uniformity and stability of the honeycomb while increasing process difficulty and cost. Therefore, simplifying the fabrication process, improving the uniformity and stability of the honeycomb structure, and reducing dependence on external adhesives are key to enhancing the overall performance of fiber-based honeycombs.  

Recently, Associate Professor Siwei Xiong from Wuhan Textile University published the latest research findings titled "Thermotropic liquid crystal-driven interfacial fusion of high-aspect-ratio polyarylate nanofibers for ultrastable honeycomb with closed-loop recyclability" in the journal **Chemical Engineering Journal**. The first author of the paper is **Jingxian Wang**, a master's student at Wuhan Textile University, with Associate Professor Xiong as the corresponding author. 

Figure 1 Schematic of PAR nanofiber honeycomb fabrication

The study employs a scalable template hot-welding process to regulate the interfacial bonding energy between nanofibers, achieving directional assembly and high-strength interfacial fusion of honeycomb unit walls. High-aspect-ratio PAR nanofibers construct a dense three-dimensional fiber network under hot-pressing, forming complex stress dissipation pathways. Compared to commercial aramid honeycombs, PAR nanofiber honeycombs exhibit superior mechanical properties while maintaining excellent mechanical stability under extreme conditions.  Furthermore, finite element simulations were used to investigate the microstructural evolution of PAR nanofiber honeycombs under external pressure. The honeycomb structure can optimize stress distribution through adaptive deformation, enhancing deformation resistance and recovery capabilities. 

Figure 2 Mechanical properties of PAR nanofiber honeycombs

As the hot-pressing temperature increases, the compressive strength, specific strength, and Young's modulus of **PAR nanofiber honeycombs** initially increase and then stabilize. When the hot-pressing temperature reaches 140°C, the compressive strength rises to 161 MPa. Further increasing the temperature to 160°C, the compressive strength enters a plateau, stabilizing at 164 MPa. This is because higher hot-pressing temperatures significantly enhance the interfacial bonding force between **PAR nanofibers**, making the three-dimensional structure denser and activating more stress dispersion points. Under external loads, this structure more effectively distributes stress, reduces localized stress concentration, and thereby improves compressive capacity and structural stability. The compressive strength, Young's modulus, and specific strength of PAR nanofiber honeycombs are approximately 41 times, 12 times, and 4 times higher than those of commercial aramid honeycombs, respectively.  

Figure 3 Finite element simulation of PAR nanofiber honeycombs under loading  

Micro-CT imaging clearly shows that PAR nanofiber honeycombs have excellent structural contrast, with uniform dimensions in length, width, and volume. The overall structure is coherent, with even thickness distribution and no significant voids or microcracks. Additionally, the internal pores are few and evenly distributed, without forming continuous large voids, further confirming the compactness of the internal structure.  Finite element simulations were used to study the compressive deformation behavior, stress transfer characteristics, and failure modes of PAR nanofiber honeycombs. The results show that compressive stress is evenly distributed throughout the honeycomb structure, with no significant stress concentration zones, indicating that the PAR nanofiber honeycomb effectively disperses external loads. This uniform stress transfer is attributed to its highly interconnected fiber network, which adapts to deformation through topological adjustments, suppressing localized stress concentration and enhancing overall structural stability.  

Figure 4 Mechanical stability of PAR nanofiber honeycombs

Honeycomb materials are widely used in aerospace, automotive, and construction industries, requiring excellent weather resistance. After 24 hours of exposure to 200°C, the compressive strength, specific strength, and Young's modulus of commercial aramid honeycombs decrease to 46.8%, 46.8%, and 26.7% of their original values, corresponding to 1.8 MPa, 38 kN·m/kg, and 21.6 MPa, respectively. In contrast, PAR nanofiber honeycombs retain 79% (126.6 MPa), 87% (251 kN·m/kg), and 89% (873.3 MPa) of their initial performance after the same aging test, far surpassing commercial aramid honeycombs.  After 24 hours of UV exposure, the compressive strength, specific strength, and Young's modulus of commercial aramid honeycombs drop to 1.9 MPa, 40 kN·m/kg, and 22 MPa, representing reductions of 49.7%, 49.7%, and 27.2%, respectively. In comparison, PAR nanofiber honeycombs exhibit only 9.7%, 7.3%, and 7.7% reductions under the same conditions, corresponding to 146 MPa, 268 kN·m/kg, and 902 MPa, demonstrating superior UV resistance.  

Figure 5 Thermal stability, flexibility, and lightweight properties of PAR nanofiber honeycombs  

Commercial aramid honeycombs show significant dimensional shrinkage, mass loss, and performance degradation under dynamic thermal loads. In contrast, the network structure of PAR nanofiber honeycombs, reinforced by strong interfacial interactions and abundant stress dispersion points, enhances overall structural stability and reduces high-temperature shrinkage and deformation tendencies. Additionally, the Y-shaped nodes of PAR nanofiber honeycombs remain intact under loads 8,000 times their own weight and can recover after deformation, demonstrating stable mechanical performance under complex loading conditions.  Notably, PAR nanofiber honeycombs also exhibit remarkable ultralight properties. In practical applications, the reversible melting behavior of PAR nanofibers enables closed-loop recyclability, significantly reducing long-term costs and providing a new technological pathway for the green and sustainable development of lightweight, high-strength structural materials.  

Paper link: [https://doi.org/10.1016/j.cej.2025.164614](https://doi.org/10.1016/j.cej.2025.164614)