Role of graphene in enhancing the mechanical properties of TiO₂/graphene heterostructures

Abstract

Graphene has been integrated in many heterogeneous structures in order to take advantage of its superior mechanical properties. However, the complex mechanical response of heterogeneous films incorporating graphene is not well understood. Here, we studied the mechanical behavior of atomic layer deposition (ALD) synthesized TiO/graphene, as a representative building block of a typical composite, to understand the mechanical behavior of heterostructures using an experiment-computational approach. The inclusion of graphene was found to significantly enhance the Young's modulus of TiO/graphene hetero-films for films below a critical thickness of 3 nm, beyond which the Young's modulus approaches that of pure TiO film. A rule-of-mixtures was found to reasonably estimate the modulus of the TiO/graphene hetero-film. Experimentally, these hetero-films were observed to fail via brittle fracture. Complimentary density functional theory and finite element modeling demonstrates strong adhesion at the graphene TiO interface and that graphene serves as a reinforcement, providing the hetero-film with an ability to sustain significantly high stresses at the point of failure initiation. The results and methodology described herein can contribute to the rational design of strong and reliable ultrathin hetero-films for versatile applications.

Nonlinear fracture toughness measurement and crack propagation resistance of functionalized graphene multilayers

“…( 31 ) reported an E of 300 N/m and a UTS of 30 N/m. Moreover, a recent paper has also reported a successful use of similar atomistic-coupled FE simulations informed by experimental fracture stresses to calculate J IC of bilayer graphene samples ( 42 ).…”

Natural SEI-Inspired Dual-Protective Layers via Atomic/Molecular Layer Deposition for Long-Life Metallic Lithium Anode

“…Four samples consisting of 10 cycles ALD (10ALD), 30 cycles MLD (30MLD), 50MLD/50ALD, and 50MLD/50ALD were deposited over single-layer graphene (used as a supporting layer) on holey transmission electron microscopy grids, and the AFM tip deflected the middle of the suspended films following a previously reported method used for thin films. 54 Prior to elastic deflection, tapping-mode AFM topography imaging was performed to identify damage-free films and also align the AFM diamond tip in the center of the holes covered with film. AFM topography imaging was also performed after elastic deflection to ensure that no damage occurred to the deflected film.…”

Fracture and Fatigue of Al2O3-Graphene Nanolayers

“…Similar modulus reinforcement effect was observed for nonfully covered TiO 2 @G films. 40 Further increasing the thickness continues to reduce the elastic modulus in a more gradual manner, and a plateau was further reached (after 30C-Al 2 O 3 @G) converging to the property of bulk amorphous alumina (within 6%), which demonstrates the minimal impact of the graphene layer on the modulus of a-Al 2 O 3 @G composites once the total thickness is above ∼3.3 nm.…”