Abstract
Perfluoropolyether (PFPE) remains a highly desirable synthetic fluid for industries like special machinery lubricants owing to its excellent chemical constancy, radiation and corrosion resistance, lubricating properties. However, like most phenomenal substances, even PFPE exhibits some shortcomings like low surface tension, which produces creeping and leakage from friction interface while in use. This manuscript reports a new method to rectify the creeping demonstrated by the PFPE lubricant, which is deemed to utilize the confinement effect of the supramolecular gel. A novel fluorine-functionalized gelator (BHD) which can gelatinize PFPE, was successfully synthesized. The results of molecular dynamics and experiment reveal that BHD compound self-assembles into spherical by interactions among the gelators and PFPE. The event of thermocapillary migration and creep behavior of the PFPE gel lubricants acting on the steel, while employing temperature gradients and exposure to the irradiation of Atomic Oxygen (AO) and Ultraviolet (UV) for 4 h was thoroughly investigated. The results reveal that the gelation of PFPE oils minimizes the thermocapillary migration of PFPE and averts the creeping from occurring at the sliding interface. The tribological representations of supramolecular gels ensure excellent lubricity and anti-wear performances under some critical environments, including ranging from high to low temperatures and irradiation in vacuum conditions. Furthermore, the supramolecular gels register that the PFPE oils are slow-release lubricants enabled by their complicated reassembling network, manifesting stronger anti-irradiation properties. These deductions make a strong case for this gel lubricant to replace PFPE lubricants administered for the lubrication of  machinery components.

Published in CHEMICAL ENGINEERING JOURNAL，Volume 409；10.1016/j.cej.2020.128120，APR 1 2021