A new type of highly temperature stable ionic liquid (IL) with strongly temperature dependent nanostructures is reported. The molecular design relies on the use of a liquid polymer with an ionic liquid headgroup, introducing liquid properties by both the polymeric and the ionic liquid (IL) headgroup. The IL polymers (poly(isobutylene)s) 3a–3c (PIB-ILs) were prepared by a combination of living carbocationic polymerization (LCCP) and subsequent “click” chemistry for attachment of methylimidazolium (3a), pyrrolidinium (3b), and triethylammonium cations (3c). All three investigated PIB-ILs exhibited pronounced nanostructural organization at room temperature depending strongly on the nature of the anchored cation. Whereas the morphology of the imidazolium-based PIB-IL 3a shows high thermal stability up to the decomposition temperature, order–order (OOT) and lattice disorder–order transitions (LDOT) characteristic for common ionomers could be observed in the case of pyrrolidinium 3b and ammonium-based 3c PIB-ILs. Control of flow behavior as well as adjustable relaxation times from the liquid to the viscoelastic regime can be adjusted by choice of the appropriate IL headgroup.

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Twelve dicationic ionic liquids have been investigated for their potential inlubricants. The dications selected were synthesized from oligoethylene glycols linking two cationic moieties based on either N-methylimidazolium or N-methylpyrrolidinium at the extremities. As anions, chloride, bis(trifluoromethanesulfonyl)imide (Tf2N), methanesulfonate and butansulfonate were chosen. Thermal stability of the IL has been evaluated by thermogravimetric analysis and differential scanning calorimetry showing good properties up to 150 °C for all IL. SRV tribotests of neat IL using steel–steel contacts with ball-on-disc geometry were performed at 50 °C, 100 °C and 150 °C. Friction and wear were significantly influenced by both anion structure and chain length of the oligoethylene glycol moiety where longer chains yielded better tribological behavior. The tribological behavior improved with a mixture of different types of ILcontaining F, O, S in their anions. A large variation of ionic liquids corrosiveness and corrosion inhibition, respectively, was found attributed to structure variation. A general tendencyof improving the corrosion resistance when increasing the chain length of the neat ILshas been found. In addition to the neat dicationic ionic liquids, mixtures of 1% of the mostinteresting IL in polypropylene glycol base oil have been studied at 100 °C resulting in more favorable tribological properties for ionic liquids with Tf2N anion. X-ray photoelectron spectroscopy analysis showed that the structures with Tf2N anion create a tribofilm of inorganic fluorine that greatly improves the performance of the base oil.

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A facile synthetic route for the preparation of dicationic ethylene glycol based-ionic liquids (ILs) via the azide/ alkyne ''click'' reaction is presented. The copper(I) catalyzed, microwave-assisted azide/alkyne ''click'' reaction between diazido-ethylene glycols and the corresponding alkyne containing IL-head group enables a simple preparation of different sets of poly(ethylene glycol)-based ILs. Beside tetra-and hexa(ethylene glycol)-based ILs, also oligomeric (M n ¼ 400 g/mol) and polymeric ILs (M n up to 1550 g/mol) could be prepared in good yield and with full conversion of the ionic head group.The prepared ILs were extensively characterized via NMR spectroscopy and ESI-time-of-flight (TOF) mass spectroscopy, revealing the formation of multiply charged ions in the negative mode. Thermal stability proved to be exceptionally high (up to 300 C) together with low glass-transition temperatures.