Effects of polyacrylic acid molecular weights on V2C-MXene nanocoatings for obtaining ultralow friction and ultralow wear in an ambient working environment

Xuan Yin; Haohao Chen; Lai Jiang; Chang Liang; Haosheng Pang; Dameng Liu; Bing Zhang

doi:10.1039/d2cp03639h

Effects of polyacrylic acid molecular weights on V₂C-MXene nanocoatings for obtaining ultralow friction and ultralow wear in an ambient working environment

Phys Chem Chem Phys. 2022 Nov 18;24(44):27406-27412. doi: 10.1039/d2cp03639h.

Authors

Xuan Yin¹, Haohao Chen¹, Lai Jiang², Chang Liang¹, Haosheng Pang^{3

4}, Dameng Liu³, Bing Zhang¹

Affiliations

¹ College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China. yinxuan@mail.buct.edu.cn.
² College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
³ State Key Laboratory of Tribology in Advanced Equipment, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China. hulk@mail.tsinghua.edu.cn.
⁴ Chinese Aeronautical Establishment, Beijing 100012, China.

PMID: 36331370
DOI: 10.1039/d2cp03639h

Abstract

Two modified V₂C-MXene nanocoatings are prepared through different molecular weights of polyacrylic acid (polyacrylic acid with ∼4 50 000 is marked as LPAA, and polyacrylic acid with ∼4 000 000 is marked as HPAA) and two-dimensional V₂C-MXene. Their properties are characterized using a ball-on-disc tribometer, three-dimensional white-light interferometry topography images, optical microscope, Raman spectrometer, focused ion beam/scanning electron microscope and high-resolution transmission electron microscope/energy dispersive X-ray spectrometer (HRTEM/EDS). As a result, an ultralow friction (μ ≈ 0.073 ± 0.024) and an ultralow wear (3.41 × 10^-7 mm³ N^-1 m^-1 for ball scar, and 7.49 × 10^-8 mm³ N^-1 m^-1 for disc track) are achieved for the LPAA@V₂C vs. steel ball system tested under 4 N in the air through tribo-physicochemical interactions. During the rubbing process, the LPAA@V₂C nanocoating is transferred onto counter-bodies to form mixed-phase lubricative tribofilms. Monitoring via a HRTEM/EDS, the mixed-phase lubricative tribofilms are found to be mainly composed of amorphous carbon phases containing O and V and layered nano-debris along the sliding surface. The tribofilm's stable structure is the key to realizing ultralow friction and ultralow wear through the LPAA modification. These findings disclose that MXene-based nanomaterials can be applied for material engineering and mechanical engineering under common working conditions.