Supramolecular polymers with reversed viscosity/temperature profile for application in motor oils

We report novel supramolecular polymers, which possess a reversed viscosity/temperature profile. To this end, we developed a series of ditopic monomers featuring two self-complementary binding sites, either the guanidiniocarbonyl pyrrole carboxylic acid (GCP) or the aminopyridine carbonyl pyrrole carboxylic acid (ACP). At low temperatures, small cyclic structures are formed. However, at elevated temperatures, a ring-chain transformation leads to the formation of a supramolecular polymer. We demonstrate that this effect is dependent on the concentration of the solution and on the polarity of the solvent. This effect can counteract the loss of viscosity of the solvent at elevated temperatures, thus opening an application of our systems as viscosity index improvers (VIIs) in working fluids. This was tested for different motor oils and led to the identification of one compound as a promising VII.

Automated summary

The study presents a novel supramolecular polymer with a reversed viscosity/temperature profile, formed by ditopic monomers that transform from small cyclic structures at low temperatures to supramolecular polymers at elevated temperatures. The effect is shown to depend on solution concentration and solvent polarity, making the system a potential viscosity index improver in working fluids.