Elmoselhy Salah A M
Department of Physics, CFisUC, The University of Coimbra, 3004 516, Coimbra, Portugal.
Condensed Matter Physics Research Group, Department of Physics, The Autonomous University of Madrid, Cantoblanco, Madrid, Spain.
Sci Rep. 2024 Sep 27;14(1):22118. doi: 10.1038/s41598-024-67605-6.
Nanotubes showed merits including high structural strength-to-weight ratio. However, tubes are less favored regarding stiffness and strength. Nano-I-beams are proposed for improved nano-mechanics. Computationally, the study proposes novel molecular designs of I-beam-like shaped structures. A conformation analysis, molecular dynamics and first principles-based optimization are presented. The study proposes options based on the configuration of the molecular nano-I-beam structure providing less number of planes of symmetry and hence more stability than nanotube-like structures. These designs feature a unique geometrical differentiator of having the walls of the out-of-plane hexagonal motif-based molecular nano-I-beam (CH) inclined with different inclination angles enabling promising properties. The stability of the proposed nano-I-beam is proved on par with the corresponding nanotube-like structure. First principles-based evidence is provided on the comparable polarizability and the comparable ability to store energy of the supercell of the crystalline slab nano-I-beam in comparison with the corresponding nanotube. A proposed hybrid octa-hexagonal-cubic molecular nano-I-beam (CH) remedies the nano-buckling observed in the alike square-octagonal nanostructure. The molecular nano-I-beam exhibits intrinsic switchability that enables the nano-I-beam to be a topological semiconductor/insulator. The results show promising electronic and elastic properties of the proposed nano-I-beams that suit several applications such as their use in capacitors, transistors, insulators, batteries, quantization-based nano-devices, solid lubricant additive to grease, toughening fibers of nanocomposites, hydrophobic films, emissions adsorbents, catalytic sensors, PAH materials for space, and sustainable energy. The molecular nano-I-beam provides the base of the corresponding 2-D crystalline slab nano-I-beams.
纳米管具有诸多优点，包括高结构强度重量比。然而，在刚度和强度方面，纳米管并不那么受青睐。人们提出了纳米I型梁以改善纳米力学性能。在计算方面，该研究提出了类似I型梁形状结构的新型分子设计。文中给出了构象分析、分子动力学以及基于第一性原理的优化。该研究基于分子纳米I型梁结构的构型提出了一些方案，这种结构具有较少的对称面，因此比纳米管状结构更稳定。这些设计的独特几何特征在于，基于面外六边形图案的分子纳米I型梁（CH）的壁以不同的倾斜角度倾斜，从而具有良好的性能。所提出的纳米I型梁的稳定性被证明与相应的纳米管状结构相当。与相应的纳米管相比，基于第一性原理的证据表明，晶体平板纳米I型梁的超胞具有可比的极化率和可比的储能能力。所提出的混合八面体 - 六边形 - 立方体分子纳米I型梁（CH）解决了在类似的方形 - 八边形纳米结构中观察到的纳米屈曲问题。分子纳米I型梁具有内在的可切换性，使其能够成为拓扑半导体/绝缘体。结果表明，所提出的纳米I型梁具有良好的电子和弹性性能，适用于多种应用，如用于电容器、晶体管、绝缘体、电池、基于量子化的纳米器件、润滑脂的固体润滑剂添加剂、纳米复合材料的增韧纤维、疏水膜、排放吸附剂、催化传感器、太空用多环芳烃材料以及可持续能源等。分子纳米I型梁为相应的二维晶体平板纳米I型梁提供了基础。
