Superior Strong and Tough Nacre-Inspired Materials by Interlayer Entanglement

Abstract

Natural materials teach that mechanical dissipative interactions relieve the conflict between strength and toughness and enable fabrication of strong yet tough artificial materials. Replicating natural nacre structure has yielded rich biomimetic materials; however, stronger interlayer dissipation still waits to be exploited to extend the performance limits of artificial nacre materials. Here, we introduce strong entanglement as a new artificial interlayer dissipative mechanism and fabricate entangled nacre materials with superior strength and toughness, across molecular to nanoscale nacre structures. The entangled graphene nacre fibers achieved high strength of 1.2 GPa and toughness of 47 MJ/m3, and films reached 1.5 GPa and 25 MJ/m3. Experiments and simulations reveal that strong entanglement can effectively dissipate interlayer energy to relieve the conflict between strength and toughness, acting as natural folded proteins. The strong interlayer entanglement opens up a new path for designing stronger and tougher artificial materials to mimic but surpass natural materials.

Bioinspired Strong and Tough Poly(ε-caprolactone)/Graphene Nanodot Composite Films via Weak Hydrogen Bonds: Implications for Thermal–Mechanical Properties

“…After loading [Figure a­(2), 0 < ε < ε b ], the H-bonds between GNDs and PCL chains can destroy and/or rebuild, which enables large deformation but retains good structural fixity . The centered-GNDs nanoconfinement can block the motion and failure of the PCL molecular chains based on the multiple H-bond effects, thus resulting in the high strength and modulus . In addition, the expansion of the large-deformation PCL chains can generate high malleability while maintaining the original stiffness .…”

“…56 The centered-GNDs nanoconfinement can block the motion and failure of the PCL molecular chains based on the multiple H-bond effects, thus resulting in the high strength and modulus. 57 In addition, the expansion of the large-deformation PCL chains can generate high malleability while maintaining the original stiffness. 58 Nevertheless, microcracks may be created in this step.…”

High Performance Nacre Fibers by Engineering Interfacial Entanglement

“…The bending deformation mode was chosen to capture the intermediate cracking features. As the bending angle (θ b ) approached 174°, a transverse crack appeared on the EGF surface, and the fracture surface has slipped laminates and pulled-out sheet tips, which can be attributed to the binding mechanism of interlayer PEO chains . As a comparison, a small crack occurred on the stretching side of PVA-EGF at a sharper bending angle (θ b = 165°), and the fiber still remained unbroken under this sharper bending deformation.…”

“…Integrating ionic and covalent bonding by Zhang et al propelled graphene nacre fibers to have an outstanding strength of 842.6 MPa and a balanced toughness of 15.8 MJ/m 3 . Recently, strong interfacial entanglement has emerged as a new strategy to promote the mechanical performances of nacre-like materials up to 1.2 GPa of strength and 46 MJ/m 3 of toughness . Beyond the sole physical entanglement, designing complex interactions of interfacial entanglement is expected to extend the performance record of nacre-inspired materials but remains unexplored.…”

“…In the new frame of interlayer entanglement, we achieved the record mechanical performance of bioinspired graphene fibers, outperforming previous enhancement strategies (Figure , Table S5, and Table S6). − ,− The high performances achieved by modulating the interlayer entanglement exhibit two trends. One is the strong and tough PVA-EGF with a high strength of 1.57 GPa and toughness of 54.3 MJ/m 3 , 30% and 15% higher than the highest record of 1.2 GPa and 47 MJ/m 3 in our previous work, far exceeding the previously reported toughening strategies, including hydrogen bonding, ionic bonding, and covalent bonding fibers at the same gauge length of 5 mm.…”