Repozitorij Univerze v Novi Gorici

Izpis gradiva
A+ | A- | SLO | ENG

Naslov:NONDESTRUCTIVE THERMAL, OPTICAL, CHEMICAL AND STRUCTURAL CHARACTERIZATION OF ADVANCED MATERIALS BY OPTOTHERMAL TECHNIQUES
Avtorji:Laboratory of Environmental and Life Sciences, University of Nova Gorica (Lastnik avtorskih pravic)
Budasheva, Hanna (Avtor)
Korte, Dorota (Mentor) Več o mentorju... Novo okno
Datoteke:.pdf Corrected_theses,_Budasheva.pdf (5,46 MB)
 
Jezik:Angleški jezik
Vrsta gradiva:Doktorsko delo/naloga (mb31)
Tipologija:2.08 - Doktorska disertacija
Organizacija:FPŠ - Fakulteta za podiplomski študij
Opis:Advanced materials are promising ones in application in fields where it is necessary to decrease energy consumption and ensure better performance at a lower cost. They are materials, which have enhanced properties compared to conventional materials in the field of their applications.1 The huge group of them contributes significantly to every aspect of our lives. Among them, chosen for the present study, are resins for passive sampling of iron species in natural water and sediments, anticorrosive coatings, and multilayered polysaccharide aerogels for medical applications. The composition and structure of each material determine its chemical, mechanical and physical properties, consequently their performance.2 The ability to use advanced materials in areas where their impact will be significant is largely dependent on the ability to precisely determine their characteristics to identify their properties that are either unique or has a better value. Therefore, the development of new methods or improvement of already known ones will make a great contribution to the development of the fields of application of the selected materials. The present study is focused on the examination of the chosen materials by determining their optical, chemical, thermal and structural properties for applying them further in the desired applications. To provide the needed characterization, optothermal techniques such as optothermal beam deflection spectrometry (BDS) and thermal lens spectrometry (TLS) are developed and applied. This dissertation is composed of the following chapters: introduction, theoretical background, optothermal techniques, research goal, part I (gels for passive sampling of iron species in natural water and sediments), part II (anticorrosive coatings), part II (polysaccharide aerogels), references. The core of this dissertation is presented in chapters 5 to 7. Each of the chapters separately covers the information about a selected group of advanced materials, including the sections describing sample preparation, developing the required characterization method, results, and conclusion. The connection link of these chapters is the study of the diffusion process of iron into different types of binding gels in passive samplers; external composites through the anticorrosive layers; drugs into the surrounding during the drug delivery process. In Part I, the BDS method for the study was chosen, it was optimized, and a detailed protocol was developed for the determination of iron in passive sampler gels. The iron residues in the initial solutions were checked by a suitably tuned TLS method. The developed technique was applied to get the iron species distribution in the gel samples deposited in the sediments in the Vrtojbica River. The method was applied to the gels applied on ice from Antarctica in order to obtain the iron species distribution on its surface as well. The obtained results were validated using the TLS, UV-Vis and ICP-MS methods. The chapter contains the analysis of the Fe diffusion depth into the resin sampler, which is presented for the first time. The information is obtained by using the mathematical model and applying it to the obtained practical results by frequency scanning of the gels. The crucial information about the thermal properties of their layers containing Fe-ions from the fitting procedure was extracted. On the basis of these results, information about the diffusion depth of Fe inside the gels was obtained, which has not been previously described in the literature. In Part II, the porosity in the anticorrosion coatings on the basis of their thermal parameters was determined. For the first time, the opened porosity was extracted from the total one. The analysis of Si/Zr-based hybrid sol-gel coatings has shown that the addition of cerium salts into the sol-gel matrix produces changes in its physical, chemical and corrosion properties. And it was found that the sample with the biggest amount of incorporated zirconium and loaded with cerium has the lowest values of porosity and, hence, the best barrier properties of the coating. The obtained thermal parameters of the Si/Zr-based hybrid sol-gel coatings by BDS were validated by the use of the photothermal radiometry method. On the other hand, the analysis of siloxane methacrylate coating has shown that the sol-gel hybrid methodology offers an important route for modification of thermal properties by a combination of inorganic to organic contents where the former than as an integral part of the coating network affects the thermal properties without the need for introducing fillers or nanoparticles. In Part III, the multilayered structure of the samples, containing hyaluronic acid, amoxicillin and fucoidan layers deposited on stainless support has been analyzed by the use of the BDS technique. The thermal parameters of each layer were determined, as well as their thickness. The results revealed the diffusion between neighboring layers and followed changes in the properties of the whole sample, which is reflected in its thermal properties. Such data for multilayered materials, which potentially can be used for drug delivery systems, are presented for the first time. Presented results indicated the ability of the BDS system for the chemical characterisation of the solid materials, the detection of their thermal parameters; investigation of total, opened and closed porosity; determining the thickness of layers in multilayered structures. The TLS method served as the validating one for the purpose of getting comprehensive information in liquid samples about their chemical composition. In summary, this dissertation explores alternative ways to apply optothermal methods to various areas of advanced materials to characterize them in order to improve their initial properties.
Ključne besede:optothermal beam deflection spectrometry, thermal lens spectrometry, diffusive gradients in thin films, iron species, anticorrosive layers, porosity, polysaccharide aerogels, multilayered structures
COBISS_ID:118995971 Povezava se odpre v novem oknu
URN:URN:SI:UNG:REP:QFUQW7PX
Število ogledov:488
Število prenosov:34
Metapodatki:XML RDF-CHPDL DC-XML DC-RDF
Področja:Gradivo ni uvrščeno v področja.
:
  
Skupna ocena:(0 glasov)
Vaša ocena:Ocenjevanje je dovoljeno samo prijavljenim uporabnikom.

Postavite miškin kazalec na naslov za izpis povzetka. Klik na naslov izpiše podrobnosti ali sproži prenos.

Sekundarni jezik

Jezik:Slovenski jezik
Naslov:NEDESTRUKTIVNA TERMALNA, OPTIČNA, KEMIJSKA IN STRUKTURNA DOLOČITEV ZNAČILNOSTI NAPREDNIH MATERIALOV S POMOČJO OPTOTERMALNIH TEHNIK
Opis:Napredni materiali so obetavni za uporabo na področjih, kjer je potrebno zmanjšati porabo energije in zagotoviti boljše delovanje ob nižjih stroških. So materiali, ki imajo izboljšane lastnosti v primerjavi z običajnimi materiali na področju njihove uporabe.1 Ogromna skupina jih pomembno prispeva k vsakemu vidiku našega življenja. Med omenjenimi, izbrani material za predstavlejno študijo, so geli za pasivno vzorčenje železovih spojin v: naravni vodi in sedimentih, protikorozijskih premazih in večplastnih polisaharidnih aerogelih za medicinsko uporabo. Sestava in struktura vsakega materiala določata njegove kemične, mehanske in fizikalne lastnosti, posledično tudi njihove lastnosti delovanja.2 Sposobnost uporabe naprednih materialov na področjih, kjer bo njihov vpliv pomemben, je v veliki meri odvisna od sposobnosti natančnega določanja njihovih značilnosti za identifikacijo njihovih lastnosti, ki so bodisi edinstvene, bodisi imajo boljšo vrednost. Zato bo razvoj novih metod ali izboljšanje že znanih v veliki meri prispeval k razvoju področij uporabe izbranih materialov. Predstavljena raziskava je osredotočena na preučevanje izbranih materialov z določitvijo njihovih optičnih, kemičnih, toplotnih in strukturnih lastnosti, za nadaljnjo uporabo v želenih aplikacijah. Za zagotovitev ustrezne karakterizacije se razvijajo in uporabljajo optotermične tehnike, kot sta spektrometrija odklona optotermičnih žarkov (BDS) in spektrometrija toplotnih leč (TLS). Doktorsko delo je sestavljeno iz naslednjih poglavij: uvod, teoretično ozadje, optotermične tehnike, cilj raziskave, I. del (geli za pasivno vzorčenje železovih spojin v naravnih vodah in sedimentih), II. del (protikorozijski premazi), II. del (polisaharidni aerogeli), literatura. Jedro te disertacije je predstavljeno v poglavjih od 5 do 7. Vsako od poglavij ločeno zajema informacije o izbrani skupini naprednih materialov, vključno z razdelki, ki opisujejo pripravo vzorcev, razvoj metode karakterizacije, rezultate in zaključek. Povezava teh poglavij je preučevanje procesa difuzije: železa v različne vrste vezivnih gelov v pasivnih vzorčevalnikih; v zunanjih kompozitih skozi protikorozijske plasti; učinkovin v okolico med postopkom dostave zdravila. V I. delu je bila izbrana metoda BDS za študijo, kjer je bil optimiziran in razvit podroben protokol za določanje železa v pasivnih gelskih vzorčevalnikih. Ostanke železa v začetnih raztopinah smo preverili z ustrezno nastavljeno metodo TLS. Razvita tehnika je bila uporabljena za določitev porazdelitve spojin železa v vzorcih gela, ki so bili odloženih v sedimentih reke Vrtojbice. Metoda z geli je bila uporabljena za določitev porazdelitve železovih spojin prisotnih na površini ledu na Antarktiki. Dobljene rezultate smo validirali z metodami TLS, UV-Vis in ICP-MS. Poglavje vsebuje analizo difuzije Fe v globino vzorčevalnika gela, ki je predstavljen prvič. Podatke smo pridobili z uporabo matematičnega modela in smo jih uporabili za pridobljene praktične rezultate s frekvenčnim skeniranjem gelov. Ključne informacije o toplotnih lastnostih njihovih plasti, ki vsebujejo Fe-ione, so bile izvlečene iz postopka prileganja. Na podlagi teh rezultatov je bila pridobljena informacija o globini difuzije Fe znotraj gelov, ki v literaturi še ni bila opisana. V II. delu je bila določena poroznost protikorozijskih premazov na podlagi njihovih toplotnih parametrov. Prvič je bila odprta poroznost ekstrahirana iz celotne. Analiza hibridnih sol-gel premazov na osnovi Si/Zr je pokazala, da dodajanje cerijevih soli v sol-gel matriko povzroči spremembe v njenih fizikalnih, kemičnih in korozijskih lastnostih. Ugotovljeno je bilo, da ima vzorec z največjo količino dodanega cirkonija in obremenjen s cerijem najnižje vrednosti poroznosti in s tem najboljše pregradne lastnosti prevleke. Dobljene toplotne parametre hibridnih sol-gel premazov na osnovi Si/Zr po BDS smo potrdili z uporabo metode fototermalne radiometrije. Po drugi strani, pa je analiza siloksanmetakrilatne prevleke pokazala, da sol-gel hibridna metodologija kaže pomembno smer za spreminjanje toplotnih lastnosti s kombinacijo anorganskih in organskih vsebin, kjer prva kot sestavni del mreže prevleke vpliva toplotne lastnosti brez potrebe po uvajanju polnil ali nanodelcev. V III. delu je bila z uporabo BDS tehnike analizirana večplastna struktura vzorcev, ki vsebujejo plasti hialuronske kisline, amoksicilina in fukoidana, nanesenega na nerjavno podlago. Določeni so bili toplotni parametri vsake plasti in njihova debelina. Rezultati so pokazali difuzijo med sosednjimi plastmi kar je prineslo spremembe lastnosti celotnega vzorca, kar se odraža v njegovih toplotnih lastnostih. Prvič so predstavljeni takšni podatki za večplastne materiale, ki jih je mogoče uporabiti za sisteme za dostavo zdravil. Predstavljeni rezultati so pokazali zmožnost sistema BDS za kemijsko karakterizacijo trdnih materialov, detekcijo njihovih toplotnih parametrov; preiskava popolne, odprte in zaprte poroznosti; določanje debeline plasti v večplastnih strukturah. Metoda TLS je služila kot validacija za namen pridobivanja izčrpnih informacij v tekočih vzorcih o njihovi kemični sestavi. Če povzamemo, ta disertacija raziskuje alternativne načine uporabe optotermalnih metod na različnih področjih naprednih materialov, kot je karakterizacija, z namenom izboljšave njihove začetne lastnosti.
Ključne besede:optotermična spektrometrija odklona žarka, spektrometrija termalnih leč, difuzijski gradienti v tankih filmih, železove spojine, antikorozijske plasti, poroznost, polisaharidni aerogeli, večplastne strukture


Nazaj