magistrsko delo
Matej Hribar (Author), Mitja Kolar (Mentor), Darinka Brodnjak-Vončina (Co-mentor), Karin Stana-Kleinschek (Co-mentor)

Abstract

Namen magistrskega dela je bil priprava novih polisaharidnih materialov in njihova karakterizacija. V prvem delu smo preučevali homogeno reakcijo sililiranja hidroksietil celuloze (HEC) in homogeno reakcijo sililiranja hitina. Skupno smo opravili 9 sintez z uporabo različnih sililirnih sredstev in pri različnih reakcijskih pogojih. Nastale produkte reakcij smo analizirali z IR spektroskopijo in preverili topnost produktov v nekaterih organskih topilih. V drugem delu pa smo se ukvarjali s pripravo tankih filmov celuloze in njenih derivatov s pomočjo ''spin-coating'' tehnike ter kemijsko in površinsko karakterizacijo le-teh. Tanke filme smo pripravili iz raztopin celuloznega acetata (CA), etil celuloze (EC), trimetilsilil celuloze (TMSC) in dvokomponentnih mešanic v različnih razmerjih. Na eni ponovitvi filmov smo izvedli tudi postopek regeneracije. Pripravili smo tudi debelejše filme in njihove regenerirane ponovitve. V zadnjem delu smo izvedli karakterizacijo tankih filmov. Za pridobitev informacij o površinskih in kemijskih lastnostih tankih filmov smo izvedli meritve stičnega kota, opravili IR spektroskopijo, izvedli meritev adsorpcije različnih proteinov na pripravljene tanke filme s tehniko QCM-D in naredili topografske meritve s tehniko AFM. Na debelejših filmih smo izvedli le meritve stičnega kota. Z reakcijami sililiranja HEC smo uspešno sintetizirali želen produkt. V primeru sililiranja hitina želenega produkta nismo uspeli sintetizirati. Nastali produkti reakcij so v organskih topilih slabo topni oz. nabrekajo. Z analizo IR spektroskopije tankih filmov smo dokazali uspešno cepitev na predvideni vezi in nastanek –OH skupine po opravljenem postopku regeneracije. Zaradi nastanka novih –OH skupin po postopku regeneracije je postala površina bolj hidrofilna, kar smo dokazali z meritvami stičnega kota. Meritve adsorpcije proteinov so pokazale, da imajo hidrofobne površine večjo težnjo po ireverzibilni vezavi govejega serumskega albumina (BSA), medtem ko ima fibrinogen visoko afiniteto do adsorpcije na površino celuloznega acetata. Razviti materiali kažejo na potencialno uporabo na področju biomedicine, kot so na primer površine senzorjev ali pa biokompatibilne plasti, ki preprečujejo obraščanje.

Keywords

celuloza;celuloznai derivati;hitin;siliranje;stični kot;adsorpcija proteinov;ATR-FTIR;AFM;QCM-D;spin-coating;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [M. Hribar]
UDC: 661.728(043.2)
COBISS: 19031830 Link will open in a new window
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Other data

Secondary language: English
Secondary title: PREPARATION AND CHARACTERIZATION OF NOVEL POLYSACCHARIDE MATERIALS
Secondary abstract: The purpose of this master thesis was the preparation of new polysaccharide materials, their characterization and their use for protein adsorption studies. In the first part of the lab work the homogeneous silylation of hydroxyethyl cellulose (HEC) and chitin were studied. In total, nine syntheses were performed by using different silylating agents and different reaction conditions. Products of the silylating reactions were analysed by IR spectroscopy. Additionally solubility test of products in certain organic solvents were carried out. In the second part of the lab work, thin films of cellulose and cellulose derivatives were prepared using the spin-coating technique. Thereafter chemical and surface characterization of thin films were performed. Thin films were prepared from solutions of cellulose acetate (CA), ethyl cellulose (EC), trimethylsilyl cellulose (TMSC) and blends of two components by different ratios. Replicate samples of thin films and macroscopic films by solvent casting were treated through regeneration processes using hydrochloric acid vapors or potassium hydroxyde solutions. In the last phase of the lab work, characterization of thin films was performed. To obtain information on surface and chemical features of thin films, measurements of static contact angle, IR spectroscopy and atomic force microscopy (AFM) were performed. Subsequently a quartz crystal microbalance (QCM-D) was used to study protein adsorption on thin films. On the thicker casted films only contact angle measurements were conducted. With the silylation of HEC the desired water insolube and partly organosoluble product was successfully synthesized. Silylation of chitin did not give the desired product and remained insoluble in organic solvents. By IR spectroscopy analysis of thin films the cleavage of the silylether bonds and the formation of –OH functional group after the process of regeneration was succesfully proven. Due to the formation of new –OH groups in the regeneration process the surface became more hydrophilic, which was shown by contact angle measurements. Protein adsorption measurements revealed that with increasing hydrophobicity more bovine serum albumine was bound irreversibly to the surfaces whereas fibrinogen turned out to have a high affinity towards cellulose acetate surfaces. The materials developed in the course of this thesis therefore have a potential to be used in the biomedical field as for instance sensor surfaces or biocompatible anti-fouling layers.
Secondary keywords: cellulose;nocellulose derivate;chitin;silylation;thin films;spin-coating;ATR-FTIR;contact angle;protein adsorption;QCM-D;AFM;
URN: URN:SI:UM:
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: XII, 67 str.
ID: 8966395