Strain‐Driven Superlubricity of Graphene/Graphene in Commensurate Contact

Abstract

The occurrence of structural superlubricity (SSL) requires that two sliding surfaces be in incommensurate contact. However, the incommensurate contact between two sliding surfaces is fundamentally an instable state whose maintenance over time is extremely laborious. To circumvent this difficulty, it is proposed in the present work to change the paradigm of making appear superlubricity and keeping it over time. Two graphene layers in sliding commensurate contact, which are subjected to an isotropic in‐plane synchronous strain, are considered and studied. First, by DFT calculations, it is demonstrated that the synchronous strain‐driven superlubricity (SSDSL) takes place for some particular sliding paths or for all sliding paths, once the compressive strain prescribed reaches 15% or 35%. Next, the Prandtl‐Tomlinson (P‐T) model is used to explain how to modulate stick‐slip, continuous and frictionless slides by the strain. Finally, the SSDSL of two graphene layers in commensurate contact is justified in detail by the interfacial charge density transfer due to the strain. The results obtained by the present work open a new perspective of realizing superlubricity in a robust way.

Superlubricity of Materials: Progress, Potential, and Challenges

“…Recent studies have shown that by manipulating the alignment of graphene layers, superlubricity can be achieved. Cheng et al [ 39 ] demonstrated that two graphene layers in sliding commensurate contact, which are subjected to an isotropic, in-plane, synchronous strain, induce superlubric behavior.…”

Long-Term Stable Superlubricity Coatings Enabled by the Interaction between the Polydimethylsiloxane Brush and Silicone Oil

“…5,6 In recent decades, the realm of exploring superlubricity in both solids and liquids has garnered significant interest in the fields of fundamental science and engineering, thus, witnessing significant strides. For solid lubrication materials, such as MoS 2 , 7 graphene, 8 hexagonal boron nitride, 9 and diamond-like amorphous carbon coatings, 10 the realization of superlubrication required some strict conditions such as the incommensurate contact state, the protection of inert gases, or an ultrahigh vacuum condition, which limited its application. 11−13 To date, liquid superlubrication systems can be divided into water-and acid-based solutions, hydrated materials, ionic liquids, 2D materials as lubricant additives, and oil-based lubrication materials.…”

“…Since it can decrease resistance and save energy, materials with superlubricity are of tremendous importance from the perspective of saving energy and protecting the environment. , In recent decades, the realm of exploring superlubricity in both solids and liquids has garnered significant interest in the fields of fundamental science and engineering, thus, witnessing significant strides. For solid lubrication materials, such as MoS 2 , graphene, hexagonal boron nitride, and diamond-like amorphous carbon coatings, the realization of superlubrication required some strict conditions such as the incommensurate contact state, the protection of inert gases, or an ultrahigh vacuum condition, which limited its application. – …”

Highly Concentrated Electrolyte Superlubricants Enhanced by Interfacial Water Competition Around Chemically Active MgO Additives

“…5,6 When COF < 0.01, it is usually considered to be a superlubricant. 7 After decades of experimental and theoretical research and development, superlubricants can be broadly categorized into two types: solid (e.g., typical graphite/ graphene, 8,9 molybdenum disulfide, 10 surface coatings, 11,12 etc.) and liquid (e.g., water/acid−based lubricants, 13,14 ionic liquids, 15−17 polyol liquids, 18 etc.).…”

“…The concept of superlubricity (i.e., the theoretical state of zero friction), which has been predicted and proposed since the 1990s, has ignited hope for addressing these concerns. , When COF < 0.01, it is usually considered to be a superlubricant . After decades of experimental and theoretical research and development, superlubricants can be broadly categorized into two types: solid (e.g., typical graphite/graphene, , molybdenum disulfide, surface coatings, , etc.) and liquid (e.g., water/acid–based lubricants, , ionic liquids, − polyol liquids, etc.).…”