A novel biomimetic strategy for improving lubrication performances of modified UHMWPE inspired by the slippery gel release behavior of chia seeds

Abstract

Friction, wear, and their induced vibrations are the major problems observed in water-lubricating polymer components of mechanical equipment, as achieving effective lubricating films remains challenging due to the low viscosity and surface tension of water. Inspired by the self-protection mechanism of chia seeds, which release slippery mucilage under aqueous conditions, a novel biomimetic composite composed of natural chia seed polysaccharide (CSP) and ultrahigh molecular weight polyethylene (UHMWPE) is proposed. Because of its hydrophilicity, CSP within the composite can easily attract water molecules through non-covalent interactions in aqueous conditions, leading to its softening, swelling, and exudation to hydrate and form a gel layer with lubricating and protective effects at the friction interface, which is similar to the behavior of chia seeds in releasing gels. The resultant composite achieves a low coefficient of friction (COF) (below 0.031), which is attributable to the synergistic effect of fluid and hydration lubrication provided by the improvement in hydrophilicity, the increase in viscosity of the water-lubricating medium, and the formation of the hydration lubrication layer. This biomimetic strategy opens up a new avenue for treating the problems of insufficient lubrication, and the proposed composite shows potential for mitigating the friction-induced vibration and noise behaviors of underwater mechanical devices.