Electrophoretic deposition of graphene-related materials: A review of the fundamentals

Graphene has received significant attention due to its combination of remarkable mechanical, thermal, chemical and electrical properties. Furthermore, due to its superior strength, graphene has great potential for use as an ultra-thin protective coating for various precision components. In this paper, the latest developments in tribological applications of graphene, theoretical simulations of graphene friction and preparation methods are reviewed. It is shown that various graphene coatings can be successfully used to decrease friction and wear in nano-, micro- and macro-mechanical applications. However, the conditions under which graphene serves as an effective protective coating depends on the operating parameters. A comprehensive review is provided with the aim to assess such characteristics of graphene.

Tribology of graphene: A review

Graphene oxide (GO) can be readily modified for particular applications due to the existence of abundant oxygen-containing functional groups. Graphene oxide-based materials (GOBMs), which are biocompatible and hydrophilic, have wide potential applications in biomedical engineering and biotechnology. In this review, the preparation and characterization of GO and its derivatives are discussed at first. Subsequently, the biocompatibility and tribological behavior of GOBMs are reviewed. Finally, the applications of GOBMs as lubricants in bio-tribological systems are discussed in detail.

https://www.mdpi.com/2075-4442/2/3/137/pdf

The Preparation of Graphene Oxide and Its Derivatives and Their Application in Bio-Tribological Systems

Facile synthesis of copper/polydopamine functionalized graphene oxide nanocomposites with enhanced tribological performance

Electrophoretic deposition of graphene-based materials: A review of materials and their applications

As a layered material, graphene oxide (GO) film is a good candidate for improving friction and antiwear performance of silicon-based MEMS devices. Via a green electrophoretic deposition (EPD) approach, GO films with tunable thickness in nanoscale are fabricated onto silicon wafer in a water solution. The morphology, microstructure, and mechanical properties as well as the friction coefficient and wear resistance of the films were investigated. The results indicated that the friction coefficient of silicon wafer was reduced to 1/6 its value, and the wear volume was reduced to 1/24 when using GO film as solid lubricant. These distinguished tribology performances suggest that GO films are expected to be good solid lubricants for silicon-based MEMS/NEMS devices.

Graphene oxide film as solid lubricant.

Confined interlayer water enhances solid lubrication performances of graphene oxide films with optimized oxygen functional groups

Transformation of Freon to 3D graphene frameworks for high-rate supercapacitors with high capacity retention

This research presents a general electrophoretic deposition (EPD) method, which offers selective preparation of various heteroatom-containing (i.e., H, Cl, F, N, and S) carboxylic acid molecular (CAM) films directly on silicon wafers, as long as the precursors are water-soluble carboxylic acids. Among them, the as-prepared fluoro-carboxylic acid (trifluoroacetic acid) molecular film with controllable thickness exhibits a longer wear life than self-assembled monolayers (SAMs), along with very low friction coefficient and a superior tolerance to humidity. It may be a promising candidate to replace SAMs as a more wear-resistant solid lubricant in micro/nano electromechanical systems (MEMS/NEMS).

A general method for the preparation of a thickness-controllable fluoro-containing organic film as a solid lubricant

To meet the lubrication demands of future MEMS/NEMS, thickness-controllable carbon films have been successfully prepared directly on silicon substrates by carbonizing electrophoresis-deposited trichloroacetic acid (TCA) molecular films. Compared with easily worn-out TCA molecular films, the transformed carbon films exhibit ultra-low friction coefficients and wear rates, along with strong adhesion to silicon substrates. These results prove that the idea of transforming organic molecular films into carbon thin films is a unique and promising approach to fabricate thickness-controllable and wear-resistant carbon-based solid lubricants for MEMS/NEMS.

Junyan Zhang

Papers

Graphene oxide film as solid lubricant.

Confined interlayer water enhances solid lubrication performances of graphene oxide films with optimized oxygen functional groups

Transformation of Freon to 3D graphene frameworks for high-rate supercapacitors with high capacity retention

A general method for the preparation of a thickness-controllable fluoro-containing organic film as a solid lubricant

Transforming organic molecular films into carbon films as solid lubricants