Insight Into the Superlubricity and Self-Assembly of Liquid Crystals.

Shanchao Tan,Yuhong Liu,Hao Jiang,Jiayu Tao,Bin Tu,Hongyu Shi,Qingdao Zeng,Haijun Xu,Wendi Luo

doi:10.3389/fchem.2021.668794

Abstract

Liquid crystals are promising molecular materials in the application of lubrication. Herein, the microscale solid superlubricity is accomplished by the construction of uniform and ordered self-assembly of several liquid crystals. The self-assembly structures on a highly oriented pyrolytic graphite (HOPG) surface are explicitly revealed by using scanning tunneling microscopy (STM). Meanwhile, the nanotribological performance of the self-assemblies are measured by using atomic force microscopy (AFM), revealing ultralow friction coefficients lower than 0.01. The interaction energies are calculated by density functional theory (DFT) method, indicating the positive correlation between friction coefficients and interaction strength. The effort on the self-assembly and superlubricity of liquid crystals could enhance the understanding of the nanotribological mechanism and benefit the further application of liquid crystals as lubricants.

Highlights

In the current industrialized world, research on tribology has been quite important to increase the components service life and save energy (Perry and Tysoe, 2005)
Superlubricity of Liquid Crystals (Shi et al, 2018), we revealed the regular nanostructures induced by hydrogen bond and van der Waals force
The self-assembly structures and superlubrication properties of liquid crystals are investigated at the molecular level

Summary

Introduction

In the current industrialized world, research on tribology has been quite important to increase the components service life and save energy (Perry and Tysoe, 2005). The current researches of solid superlubricity mainly focus on the inorganic materials such as molybdenum disulfide (MoS2) (Martin et al, 1993), graphite (Mate et al, 1987), and graphene (Ge et al, 2018). Compared to these inorganic solid superlubricity materials, liquid crystals have modifiable functional groups, which makes it possible to tailor unique functionalities and combine them with superlubricity to explore further application. The effort on the superlubricity of liquid crystals could extend the research field of solid superlubricity from inorganic to organic and benefit the further application of solid superlubricity. In our previous research on self-assembly of template networks

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Conclusion