Oil-Soluble Polymer Brush Grafted Nanoparticles as Effective Lubricant Additives for Friction and Wear Reduction.
The development of high performance lubricants has been driven by increasingly growing industrial demands and environmental concerns. Herein, we demonstrate oil-soluble polymer brush-grafted inorganic nanoparticles (hairy NPs) as highly effective lubricant additives for friction and wear reduction. A series of oil-miscible poly(lauryl methacrylate) brush-grafted silica and titania NPs were synthesized by surface-initiated atom transfer radical polymerization. These hairy NPs showed exceptional stability in poly(alphaolefin) (PAO) base oil; no change in transparency was observed after being kept at -20, 22, and 100 °C for ≥55 days. High-contact stress ball-on-flat reciprocating sliding tribological tests at 100 °C showed that addition of 1 wt % of hairy NPs into PAO led to significant reductions in coefficient of friction (up to ≈40 %) and wear volume (up to ≈90 %). The excellent lubricating properties of hairy NPs were further elucidated by the characterization of the tribofilm formed on the flat. These hairy NPs represent a new type of lubricating oil additives with high efficiency in friction and wear reduction.
Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
Roger A E
RA
Wright
Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA.
Kewei
K
Wang
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA. qujn@ornl.gov.
Jun
J
Qu
Department of Chemistry, University of Tennessee, Knoxville, TN, 37996, USA. bzhao@utk.edu.
Bin
0000-0001-5505-9390
B
Zhao
friction reduction; lubricant additives; nanoparticles; polymer brushes; polymerization