Laxative Inspired Ionic Liquid Lubricants with Good Detergency and No Corrosion

1-Alkyl-3-methylimidazolium bis­(2-ethylhexyl)­sulfosuccinate (L-DOSS10n, <i>n</i> = 2, 4, 8) ionic liquids (ILs) were synthesized from dioctyl sodium sulfosuccinate (NaDOSS), which is a cheap, bulk available laxative medicine used for the treatment of constipation. The ILs showed lower corrosion levels and higher hydrolysis stabilities than conventional ILs such as 1-butyl-3-methyl imidazolium tetrafluoroborate (L-B104) and 1-butyl-3-methyl imidazolium bis­(trifluoromethylsulfonyl)­imide (L-F104) due to their halogen-free characteristic. The tribological properties of the ILs were also better than those of L-B104 and L-F104 for various contacts. Thus, they can be used as replacements for conventional IL lubricants, which may solve the problems of corrosion and high cost to put conventional IL lubricants into industrial application. Coking test results indicated that the synthesized ILs have high deterging ability. Thus, these ILs may be used as lubricants that restrain carbonaceous deposition as well as oil sludge and varnish formation on the metal contacts during the sliding process. Moreover, the synthesized ILs can disperse, loosen, and remove the already formed harmful substances and keep the metal contacts clean

Thermoreversible Gel Lubricants through Universal Supramolecular Assembly of a Nonionic Surfactant in a Variety of Base Lubricating Liquids

The present paper investigates a new type of thermoreversible gel lubricant obtained by supramolecular assembly of low-molecular-weight organic gelator (LMWG) in different base oils. The LMWG is a nonionic surfactant with polar headgroup and hydrophobic tail that can self-assemble through collective noncovalent intermolecular interactions (H-bonding, hydrophobic interaction) to form fibrous structures and trap base oils (mineral oils, synthetic oils, and water) in the as-formed cavities. The gel lubricants are fully thermoreversible upon heating-up and cooling down and exhibit thixotropic characteristics. This makes them semisolid lubricants, but they behave like oils. The tribological test results disclosed that the LMWG could also effectively reduce friction and wear of sliding pairs compared with base oils without gelator. It is expected that when being used in oil-lubricated components, such as gear, rolling bearing, and so on, gel lubricant may effectively avoid base oil leak and evaporation loss and so is a benefit to operation and lubrication failure for a long time