Work

Bulk conformation and shear-induced transitions in bottlebrush poly(alkyl methacrylate): The role of side chain length and polymer flexibility

Year: 2024

Type: article

Abstract: Optimal design of polymeric friction modifiers (PFMs) in lubricating oils is crucial for enhancing energy efficiency. This study examines the impact of side chain length on the flexibility and conformation of bottlebrush PFM poly(alkyl methacrylate) in bulk oil solutions and under shear using molecular dynamics simulations. We semi-quantify polymer flexibility through cluster analysis, revealing coil-globule transitions at varying temperatures. Under shear, polymers exhibit translational and rotational motion with conformational changes, driven by shearing and temporary surface adsorption. A concentrated distribution of adsorbed atoms is crucial for stable adsorption in the subsequent translational phase. Polymers with shorter side chains demonstrate stable adsorption with a coil conformation, while those with longer side chains lack stable adsorption, repeating translation-rotation cycles and coil-globule transitions.

Source: Tribology International

DOI: 10.1016/j.triboint.2024.110476

Authors: Himanshu Shekhar, Yuma Chikazawa, Yuxi Song, Hedong Zhang

Institution: Nagoya University

Language: English

Topic: Lubricants and Their Additives

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $5,230

Funders: Ministry of Education, Culture, Sports, Science and Technology, Japan Society for the Promotion of Science