Developement of ionic liquid composites by sol-gel method for elaboration of industrial nano- and microstructures
Date
2014-07-03
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Abstract
Doktoritöö teemaks oleva ioonsete vedelike ja sool-geel meetodi kombineerimine funktsionaalsete komposiitide loomisel on alles viimasel kümnendil kujunenud teadussuund. Ioonsed vedelikud on keemiliselt üsna inertsed, suurepärase temperatuuritaluvuse ning ioonse juhtivusega ained. Suur huvi antud matejalide klassi vastu on seotud nende madala omahinna ja valmistamismetoodika lihtsusega. See loob äärmiselt konkurentsivõimelise alternatiivi juhtivate ja/või läbipaistvate materjalide väljatöötamoiseks, samuti nanomõõdus osakeste sünteesimeetodite arendamiseks. Viimane on oluline funktsionaliseeritud tekstiili erinevates rakendustes. Ioonse vedeliku kasutust piirab tihti aine vedelas olekus esinemine, seega oli vajalik luua uus tehnoloogia ioonsete vedelike talletamiseks tahkesse võrgustikku.
Viimastel aastatel on mõnede ioonsete vedelike stabiilsus ja ohutus keskkonna suhtes olnud uurimuse keskmes ning paljud seni kehtinud tõed on sattunud küsimärgi alla. Töös näidati, et seni “roheliseks” peetud teatud tüüpi ioonsed vedelikud hüdrolüüsuvad niiskes keskkonnas juba toatemperatuuril. Olles hüdrolüüsumise käigus kontaktis teiste materjalidega (nt. klaas, oksiidid, keraamika) avastati esmakordselt uudsete hübriidsete kahekomponentsete kristallide teke.
Töö eesmärgiks oli ioonsetel vedelikel ja metalli alkoksiididel põhinevate tahkete ioonvedelike/oksiidide koposiitide sünteesimeetodite väljatöötamine ning saadud struktuuride omaduste ja rakendusvõimaluste selgitamine. Selleks sünteesiti funktsinaliseeritud ioone vedelik mis sobib alkoksiididega komposiitide loomiseks ja mis säilitasid ioonsele vedelikule iseloomulikud omadused. Sool-geel meetodile analoogselt anti geelile, geel+ioonsele vedelikule ning geel+ioonsele vedelikule koos süsiniknanotoruga soovitud kuju ja suurus (rullid, fiibrid, kiled). Sünteesitud homogeenseid ioonse vedeliku ja metallialkoksiidi segusid testiti funktsionaliseeritud tekstiili valmistamisel. Näidati, et ionogeeliga töödeldud puuvilla kiududel suureneb tõmbetugevus, hüdrofoobsus ning kulumiskindlus võrreldes algse materjaliga.
The main aim of this research was to develop methods for synthesizing solid ionic liquid – gel and oxide composites based on ionic liquids and metal alkoxides, and to clarify properties and applications of formed structures. The topic of the thesis – combining ionic liquids and sol-gel method to create functional composites – is a relatively novel research field and has been developing during last decade. Ionic liquids are chemically rather inert, thermally stable materials with ionic conductivity. This class of materials is highly popular because of the rather low production costs and the simplicity of synthesis methods, which induce extra competitive alternative for production of conductive and/or transparent electrolytes, nanoparticle synthesis, or functionalized textiles for different applications. The main problem for creating alternative technologies for combining liquids into a solid is a fundamental contradiction between the liquid and solid mechanisms where improving one typically diminishes another. Nevertheless, materials' advantageous liquid state turns out to be an impediment for applications in devices which need stable solid state shaping. In addition, it is important for industry to find alternative materials and technologies for designing hybrid materials with unique properties. In current thesis it was shown that some „green“ ionic liquids hydrolyse already at the room temperature. Thereby novel hybrid dual-component crystals were discovered for the first time, which formed during the hydrolysis when in contact with other substances (e.g. glass, oxides, ceramics). Special functionalized ionic liquid was synthesized to obtain solid homogeneous structures using sol gel method, by giving them curtain shape and size. Synthesized mixtures of ionic liquid and metal alkoxide were implemented in developing functionalized textiles. It was shown that cotton threads treated with ionogel have better breaking strencht, hydrophobic qualities, and wearproof compared to starting material.
The main aim of this research was to develop methods for synthesizing solid ionic liquid – gel and oxide composites based on ionic liquids and metal alkoxides, and to clarify properties and applications of formed structures. The topic of the thesis – combining ionic liquids and sol-gel method to create functional composites – is a relatively novel research field and has been developing during last decade. Ionic liquids are chemically rather inert, thermally stable materials with ionic conductivity. This class of materials is highly popular because of the rather low production costs and the simplicity of synthesis methods, which induce extra competitive alternative for production of conductive and/or transparent electrolytes, nanoparticle synthesis, or functionalized textiles for different applications. The main problem for creating alternative technologies for combining liquids into a solid is a fundamental contradiction between the liquid and solid mechanisms where improving one typically diminishes another. Nevertheless, materials' advantageous liquid state turns out to be an impediment for applications in devices which need stable solid state shaping. In addition, it is important for industry to find alternative materials and technologies for designing hybrid materials with unique properties. In current thesis it was shown that some „green“ ionic liquids hydrolyse already at the room temperature. Thereby novel hybrid dual-component crystals were discovered for the first time, which formed during the hydrolysis when in contact with other substances (e.g. glass, oxides, ceramics). Special functionalized ionic liquid was synthesized to obtain solid homogeneous structures using sol gel method, by giving them curtain shape and size. Synthesized mixtures of ionic liquid and metal alkoxide were implemented in developing functionalized textiles. It was shown that cotton threads treated with ionogel have better breaking strencht, hydrophobic qualities, and wearproof compared to starting material.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone.
Keywords
ioonsed vedelikud, sool-geel protsessid, mikrostruktuur, nanostruktuursed materjalid, ionic liquids, sol-gel processes, microstructure, nanostructured materials