Fabrication of Dialkyl Dithiophosphate-Functionalized Carbon Aerogel Microspheres for Enhanced Lubrication Performance

Herein, functionalized carbon aerogel microspheres (CAMs) were successfully prepared by the pyrolysis of resorcinol-formaldehyde (RF) microspheres followed by surface modification. First, RF microspheres were carbonized to obtain CAMs. Afterward, the polyphenolic compound of epigallocatechin gallate (EGCG) was reacted with melamine to form a poly(EGCG) layer onto the CAM surface, followed by bonding the antiwear molecule dialkyl dithiophosphate (DDP) by the Michael addition, resulting in DDP-functionalized CAMs (DDP-CAMs). The grafting antiwear molecule DDP improved the lipophilicity of the CAMs, enabling stable dispersion in the base oil 500SN for over 10 days while also enhancing their antifriction and antiwear properties. The addition of 1.0 wt % DDP-CAMs to 500SN resulted in a 34.7% reduction in coefficient of friction and a 47.5% decrease in wear volume. The enhanced lubrication performance can be attributed to a synergistic effect. On one hand, a protective film was generated through tribo-chemical reactions. At the same time, the DDP-CAMs present at the contact interface exhibited a nanoscale rolling and self-repairing effect.