Ionic liquids: synthesis and application in lubrication and lithography

Abstract

Vajadus uute lubrikandite ja kulumisevastaste õlilisandite vastu on suurenenud, kuna masinatel on pikemad hooldusintervallid, ekstreemsemad kasutustingimused ning uued regulatsioonid emissioonide vähendamiseks. Ioonsed vedelikud on sulas olekus soolad, millel on unikaalsed omadused (madal lenduvus, kõrge termiline stabiilsus) ja hiljuti on nad näidanud häid omadusi lubrikantidena. Nanoosakesed on osakesed, mille suurus jääb 1-100nm vahemikku. Nanoosakesi on samuti uuritud kui lubikandi lisandeid nende suure koormustaluvuse ja hõõrdepinda parandavate omaduste tõttu. Antud doktoritöös uuriti erinevate ioonsete vedelike sünteese. Ioonse vedeliku funktsionaalne -OH rühm mängib olulist rolli nanoosakeste funktsionaliseerimisel ja ioonse vedeliku adsorptsioonil metalli pinnale. Ioonseid vedelikke ning nanoosakesi uuriti nii lubrikandina kui ka lubrikandi lisandina, ning triboloogilised mõõtmised näitasid kuni 60% paremaid tulemusi. On väga oluline saavutada stabiilne nanoosakeste (süsiniknanotorude, vase, titaandioksiidi) dispersioon ja selle saavutamiseks kaeti nanoosakesed sobiva kihiga. Veel üks huvitav rakendus ioonsetele vedelikele oleks mikrofiibrite valmistamine in situ SEM. Näidati, et ioonse vedeliku hüdroksüülrühm on väga oluline polümerisatsiooni/tahkestamise protsessil ja mõjutab mehaanilisi omadusi.

New lubricants and improved antiwear additives are in need, because of increased service intervals, extreme conditions and regulations to reduced emissions. Ionic liquids are molten salts, which have unique properties (low volatility, high thermal stability) and recently have shown many advantages in this area. Nanoparticle is a small particle with size between 1-100nm. They have also been reported as lubricant additives due to their high-load tolerance and self-repair function to wear surface. In the present thesis the synthesis of different ionic liquids was investigated. Moreover, task-specific imidazolium based ionic liquids with -OH groups are important for nanoparticle functionalization and ionic liquid adsorption to metal surfaces. Different ionic liquids and nanoparticles were investigated as lubricant and as lubricant additive and tribological measurements showed even up to 60% better performance. It is very important to achieve a stable dispersion of nanoparticles (carbon nanotubes, copper, titanium oxide) and therefore nanoparticles where cover with suitable layer. Another interesting new application of ionic liquids is production and manipulation of microcantilevers in situ in SEM. It was shown that the hydroxyl group of ionic liquid has an important role in the polymerization/solidification process and affects the mechanical properties.