Structural-Defect-Mediated Grafting of Alkylamine on Few-Layer MoS2 and Its Potential for Enhancement of Tribological Properties
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2020-06-11 |
| Journal | ACS Applied Materials & Interfaces |
| Authors | Sangita Kumari, Ajay Chouhan, Om P. Sharma, Sruthi Kuriakose, Sherif Abdulkader Tawfik |
| Institutions | Academy of Scientific and Innovative Research, Indian Institute of Petroleum |
| Citations | 41 |
Abstract
Section titled āAbstractāTwo-dimensional transition-metal dichalcogenides possess inherent structural characteristics that can be harnessed for enhancement of tribological properties by making them dispersible in lube media. Here, we present a hydrothermal approach to preparing MoS<sub>2</sub> nanosheets comprising 4-10 molecular lamellae. A structural-defect-mediated route for grafting of octadecylamine (ODA) on MoS<sub>2</sub> nanosheets is outlined. The unsaturated d orbitals of Mo at the sulfur vacancies on the MoS<sub>2</sub> surface are coupled with the electron-rich nitrogen center of ODA and yield ODA-functionalized MoS<sub>2</sub> (MoS<sub>2</sub>-ODA). The MoS<sub>2</sub>-ODA nanosheets exhibit good dispersibility in lube base oil and are used as an additive (optimized dose: 0.1 mgĀ·mL<sup>-1</sup>) to mineral oil. It is shown that even at low concentration, MoS<sub>2</sub>-ODA nanosheets significantly reduce the friction (48%) and wear (44%). Microscopy (field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM)) and spectroscopy (Raman and elemental mapping) analyses of worn scars revealed the formation of MoS<sub>2</sub>-based protective thin films for lowering of friction and wear. This work, therefore, presents a pathway for low-friction lubricants by deploying functionalized low-dimensional material systems.