Extreme Mechanical Behavior of Nacre-Mimetic Graphene-Oxide and Silk Nanocomposites

Abstract

Biological materials have the ability to withstand extreme mechanical forces due to their unique multilevel hierarchical structure. Here, we fabricated a nacre-mimetic nanocomposite comprised of silk fibroin and graphene oxide that exhibits hybridized dynamic responses arising from alternating high-contrast mechanical properties of the components at the nanoscale. Dynamic mechanical behavior of these nanocomposites is assessed through a microscale ballistic characterization using a 7.6 μm diameter silica sphere moving at a speed of approximately 400 m/s. The volume fraction of graphene oxide in these composites is systematically varied from 0 to 32 vol % to quantify the dynamic effects correlating with the structural morphologies of the graphene oxide flakes. Specific penetration energy of the films rapidly increases as the distribution of graphene oxide flakes evolves from noninteracting, isolated sheets to a partially overlapping continuous sheet. The specific penetration energy of the nanocomposite at the highest graphene oxide content tested here is found to be significantly higher than that of Kevlar fabrics and close to that of pure multilayer graphene. This study evidently demonstrates that the morphologies of nanoscale constituents and their interactions are critical to realize scalable high-performance nanocomposites using typical nanomaterial constituents having finite dimensions.

Atomically Thin Polymer Layer Enhances Toughness of Graphene Oxide Monolayers

“…In this regard, the fundamental studies of the mechanics of nanolaminates described in this paper provide key understandings of the pathways for their toughening and explain recent experimental findings hinting at the potential of 2D materials in transportation and ballistic-protection applications. 9 Indeed, the ultrathin GO-PVA structures reported here show significant failure resistance while preserving good stiffness and light weight. The GO monolayers are significantly toughened by atomically thin layers of PVA through controlled interfacial interactions: the microscale cracks are bridged by the PVA chains, which delay and shield crack growth through a hydrogen-bond-mediated network.…”

“…For instance, it has been shown that graphene and graphene oxide-polymer systems have the potential to offer superior performance to Kevlar in body armor applications. [7][8][9] Likewise, graphene/Al 2 O 3 has been utilized as reinforcing components in lightweight aluminum composites. 10 Unfortunately, the presence of ''architectural defects'' such as voids and wrinkles found in previously produced 2D materials, in thin-film form, resulted in limited mechanical performance.…”

Impact resistance of nanocellulose films with bioinspired Bouligand microstructures

“…55 In addition, the ratio between projectile radius and lm thickness is relatively small compared to standard thin lm LIPIT. 53,62,63 The small ratio in this work was purposely chosen to investigate and highlight the frictional effects in the thickness direction on the impact response of lms, similar to a previous experimental study on high strain rate deformation of layered nanocomposites using LIPIT. 52 This is because when the projectile radius is orders of magnitude larger than the lm thickness, the deformation in the thickness direction of the lm can be usually treated as uniform and the interlayer friction inside the lm would be negligible.…”

Fabrication of silk fibroin/poly(lactic-co-glycolic acid)/graphene oxide microfiber mat via electrospinning for protective fabric

“…GO with a higher specific surface area and abundant functional groups has wide applications in cell adhesion, reinforcing material and antibacterial activity [35,36]. GO can easily form hydrogen bonds with the hydrophilic amide groups in silk fibroin (SF) because GO contains lots of oxygen functional groups [37,38].…”