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Stimuli - responsive nanoparticles with boronic ester linkages as a potential carrier for drug delivery
Hlavatovičová, Eva ; Uchman, Mariusz Marcin (advisor) ; Strachota, Adam (referee)
This thesis deals with the post-polymerization functionalization of a pH-responsive poly(styrene)-b-poly(4-vinyl pyridine)-b-poly(ethylene oxide) triblock terpolymer with stimuli responsive and diol-binding 2-bromomethyl-4-fluorophenylboronic acid and 2- bromomethyl-phenylboronic acid suitable for biomedical applications. A reproducible method of quaternization of poly(4-vinyl pyridine) block with prescriptible quaternization ratio was developed and the reaction yield was analyzed by 11 B, 1 H NMR and infrared spectroscopy. A reproducible self-assembly protocol for stable nanoparticles from functionalized stimuli-responsive triblock terpolymer was found, and the nanoparticles were studied by static, dynamic and electrophoretic light scattering, and cryogenic transmission electron microscopy. Fluorescence and UV-VIS spectroscopy measurements were performed for description of boron-ester linkages formation and hydrolysis with model drug Alizarin as a study of encapsulation and release reactions together with sugar sensing reactions for potential drug delivery.
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Synthesis of block copolymers by ring-opening polymerization and post polymerization modification with phenylboronic acid
Dudičová, Dorota ; Uchman, Mariusz Marcin (advisor) ; Strachota, Adam (referee)
This thesis deals with the synthesis of propargyl-functionalized amphiphilic diblock copolymers, poly(ε-caprolactone)-b-poly(ethylene oxide), PgCL-PEO via Ring Opening Polymerization (ROP) using monohydroxyl-terminated PEO block as the macroinitiator and its post polymerization modification via Copper-Catalyzed Azide-Alkyne Click reaction (CuAAC) to introduce phenylboronic acid functionality into block copolymers. A reproducible synthetic protocol was developed for preparation of well-defined functional diblock copolymers. The amphiphilic block copolymers were characterized in terms of molecular weight and dispersity by various techniques: Nuclear Magnetic Resonance (NMR) spectroscopy, Gel Permeation Chromatography (GPC) and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI ToF) Mass Spectrometry. Keywords: Amphiphilic block copolymers, CuAAC click, phenylboronic acid, poly-ε- caprolactone, ring-opening polymerization
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Novel conjugated polymers of the metallo-supramolecular and polyelectrolyte class
Hladysh, Sviatoslav ; Vohlídal, Jiří (advisor) ; Strachota, Adam (referee) ; Jindřich, Jindřich (referee)
This thesis targets the development of conjugated polymers with improved process ability from solutions. Two types of ionic polymers are addressed: (i) conjugated metallo-supramolecular polymers (MSPs) composed of conjugated heteroaromatic unimers (building blocks) linked to chains by various metal ions giving charged main chains, and (ii) polythiophene polyelectrolytes containing ionic pendants. Processing advantages of conjugated polyelectrolytes consist in the possibility of their processing from solutions in green solvents such as alcohols or even water. The advantages of MSPs consist in the thermodynamic control of the degree of polymerization (length) of their chains in solutions by the choice of solvent and temperature. As a result, MSPs reversibly provide systems of low viscosity that can be processed from solutions more easily than high-molar-mass polymers giving highly viscous solutions. Synthesis of appropriately designed unimer(s) is the key step of preparation of an MSP. Within this thesis, a series of novel unimers composed of linear oligothiophene type (mono-, bi-, ter- a thieno-thiophene- diyl) central blocks capped with 2,6-bis(oxazoline-2-yl)pyridine (pybox) or 2,6-bis(imidazole-2-...
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Organic-inorganic polymers - synthesis and characterization of hybrid polymers and nanocomposites
Depa, Katarzyna ; Strachota, Adam (advisor) ; Matějka, Libor (referee) ; Sedláček, Jan (referee)
In the first part of this work, silica nanoparticles and alternative or additional filler phases were incorporated into hydrogels based on the temperature-sensitive poly(N- isopropylacrylamide) (PNIPAm). Nano-SiO2-filled porous PNIPAm hydrogels with an enhanced force response (up to 100 g) to temperature stimuli were obtained by increasing several times the pore wall thickness, which was achieved via reducing the solvent (porogen) content during the gels' cryo-synthesis. A similar optimization of the force response was also carried out for analogous gels reinforced by nano-TiO2, in which the reinforcing effect of the filler is weaker. Partial intercalation of amylopectin starch into divinyl-crosslinked bulk as well as porous PNIPAm gels several times improved their extensibility. In case of starch-rich bulk gels, a very fast and extensive one-way deswelling in response to increased temperature was achieved (re-swelling upon cooling is much slower), which is attributed to specific properties of the starch-PNIPAm interface. In doubly-filled bulk PNIPAm/nano-SiO2/starch gels, a very strong synergic reinforcing effect of both fillers is observed, due to specific hydrogen bridging between the three phases. Highly porous cryogels based on PNIPAm/nano- SiO2/starch displayed a highly improved extensibility...
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Fluorometric detection of sacharides based on phenylboronic acids
Pechrová, Zdislava ; Matějíček, Pavel (advisor) ; Strachota, Adam (referee)
This paper deals with influence of fructose, glucuronic acid, glucose and mannose on the fluorescence characteristics of probe Click fluor using stationary and time resolved fluorescence spectroscopy. The spectra were measured for a wide range of concentrations (up to 3M), and the change in fluorescence intensity after the addition of carbohydrate was used to calculate the binding constants of the Click fluor/saccharide complex. Also time resolved fluorescence was measured for glucose and fructose, The last topic was the linking of Click- fluor to poly(ethylene glycol), PEG, with glucose at the end of the chain, glc-PEG-glc. The measurements show that the affinity of the Click-fluor for fructose is the greatest, on the other hand formation of the ester with glucose is very weak. Three strips were observed in the emission spectrum. One corresponds to the unbound probe, the second unstable ester form with sugar, and the third stable cyclic form of the sugar ester. In the time-resolved fluorescence of Click-fluor, changes in the wavelengths corresponding to the carbohydrate ester were seen, but not too pronounced. From the emission spectra of complex Click- fluor/glc-PEG-glc polymer and even lifetime fluorescence values, suggests that there is relatively strong binding of the probe to the...
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Self-assembling hybrid nanomaterials
Rodzeń, Krzysztof ; Strachota, Adam (advisor) ; Svoboda, Jan (referee) ; Matějíček, Pavel (referee)
Organic-inorganic polymer hybrids containing butyl stannoxane dodecamer cages (Sn_POSS) as nano-building blocks were prepared and investigated. Sn_POSS was employed as a linear, crosslinking or non-bonding molecularly blended unit. For this purpose, it was synthesized with two acrylamido, primary- or secondary amino, or with two additional non- functional groups, which were attached via ionic-bonded sulfonate substituents. The nano- building block was then incorporated in matrices such as PS, PAOS, PETA, PEMA, PHEMA and PPO-based epoxies (the latter with different mesh sizes). Sn_POSS reinforces the studied matrixes by filler-filler interactions (self-assembly to nano-domains). Specific interactions of the ionic bonds of Sn_POSS with suitable pendant groups of the matrixes also can generate reinforcement and suppress filler aggregation. Moreover, the Sn_POSS can undergo several types of chemical reactions like heat-induced oligomerization, dissociation of the ionic substituents, acidolysis of the Sn-butyl bonds, as well as radical reactions of the latter. The influence of ionically bonded cages on the hybrids' morphology, as well as their ability of dissociation and short-distance migration in the polymer network at elevated temperature, was evaluated by TEM, IR and NMR analyses. The mechanical...
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Synthesis and characterization of new polymers of substituted acetylenes
Sivkova, Radoslava Parusheva ; Vohlídal, Jiří (advisor) ; Strachota, Adam (referee) ; Sedlařík, Vladimír (referee)
New procedures for preparation of polyacetylenes with highly luminescent naphthalimide groups that might be potentially utilized in optoelectronics and sensors are developed within the framework of present doctoral thesis. The procedures provide luminescent a) linear polyacetylenes that can be processed from solutions, and b) mesoporous network polyacetylenes with high pore volume. Two paths to soluble polyacetylenes are used: (i) copolymerization of ethynyl- functionalized naphthalimide (monomer PN) and a monoethynyl aromate catalyzed with [Rh(nbd)acac], and (ii) modification of poly(disubstituted acetylene)s carrying -chloroalkyl pendants involving the exchange of chlorine atoms for azido groups and subsequent "click"- reaction of Huisgen type of azido groups with ethynyl groups of PN. The PN does not homopolymerize but copolymerizes with ethynylaromates. The highest possible molar fraction of the PN units in copolymers is of 0.5, which suggests the absence of PN dyads or longer sequences in copolymers and the alternating arrangement of PN units in the copolymers of the composition of 0.5. Surprisingly, ethynylarenes that give insoluble homopolymers gave soluble copolymers with PN. The modification procedure requires knowledge on the effect of the monomer structure symmetry and substituent...
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Synthesis and properties of conjugated metallo-supramolecular polymers
Štenclová, Pavla ; Svoboda, Jan (advisor) ; Jindřich, Jindřich (referee) ; Strachota, Adam (referee)
More than twenty new bis(tpy)oligothiophenes (tpy stands for 2,2':6',2''-terpyridin-4'-yl) with unsubstituted as well as substituted (with methyl, hexyl, bromohexyl or 6-(4- methoxyphenoxy)hexyl groups) central blocks comprising one to four thiophene rings have been prepared as building blocks (unimers) for constitutional dynamic metallo- supramolecular polymers (MSPs) soluble in common organic solvents. In addition a series of ionic unimers soluble in alcohols and partially in water have been prepared by modification of bromohexyl unimers with trimethylamine or triethylphosphine. Spectroscopic studies have shown that the steric hindrances prevail over the electronic effects of substituents as regards the impact on the delocalization of electrons along unimer chains. Unimers with high steric hindrances in the middle of the central oligothiophene block were found to behave nearly like the unimers with half central block. Three stages of the assembly of MSPs from unimers and metal ions in solutions were characterized by the exclusion chromatography: (i) formation of dimers U-Mt2+ -U in the early stages of assembling, (ii) assembly to longer MSPs chains, and (iii) end-capping with surplus metal ions and partial decomposition of MSPs chains. The observed changes in optical absorption spectra indicate a...
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Preparation and characterization of bis(terpyridyl)fluorene based polymers
Hrma, Martin ; Svoboda, Jan (advisor) ; Strachota, Adam (referee)
The diploma thesis presents the preparation of ,-bisterpyridinylfluorenes (unimers) containing fluorene unit in the central block either directly attached to terpyridine (tpy) end groups or via 1,4-phenylene or thiophene-2,5-diyl linker. Synthesized unimers were subsequently used for the preparation of metallo-supramolecular polymers with Zn2+ and Fe2+ ions. The prepared unimers were characterized by NMR, IR and HR-MS, their optical properties were investigated using absorption and emission spectroscopy and cyclic voltammetry. Molecular weight distribution for the prepared Fe-polymers was determined by GPC. The number-average degree of polymerization equal to 7 for an equimolar ratio between unimer and Fe2+ in a diluted solution was determined for polymers composed of unimer with thiophene-2,5- diyl linker. By using the viscometric measurements the ongoing constitutional dynamics in solutions of metallo-supramolecular polymers was proven. The overstoichiometric amount of metal ions in solution resulted in equilibrium shortening of the polymer chains together with end-capping of terminal tpy ligands by Mt2+ ions. Unimer with thiophene-2,5-diyl linker exhibited unique properties involving significantly red-shifted absorption and emission maxima, as well as the different behavior during assembling...
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