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Smart hybrid gels
Strachota, Beata Katarzyna ; Matějka, Libor (advisor) ; Matějíček, Pavel (referee) ; Krakovský, Ivan (referee)
This Thesis is dedicated to the development of mechanically reinforced thermoresponsive hydrogels, able of fast and extensive temperature-induced volume transition. Poly(N-isopropylacrylamide)- (PNIPA-) based hydrogels crosslinked with Laponite clay nano-platelets, which are known for their extraordinary mechanical properties, were synthesized by free radical polymerization of the NIPA monomer in the presence of exfoliated clay nanoplatelets. In this work, the crucial role of the employed redox initiators in the formation of the physical PNIPA/clay network was established, and the particular processes taking place during the polymerization and network structure formation were described. The correlation of the time-dependent NIPA monomer conversion and of the observed structure-formation stages made possible to propose a general mechanism of the PNIPA/clay hybrid gel formation. Generally, a considerable attention was paid to the investigation of the formation-structure-property relationships. This knowledge makes it possible to control the structure evolution and hence the final material properties of the gels. An important part of this work is dedicated to the study of mechanical properties of the PNIPA/clay nanocomposite hydrogels and of the parameters which control them. The gained knowledge of...
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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-assembly of boron cluster compounds and their coassembly with polymers
Ďorďovič, Vladimír ; Matějíček, Pavel (advisor) ; Adamczyk-Wozniak, Agnieszka (referee) ; Nunez Aguilera, Maria Rosario (referee)
This thesis focuses on the self-assembly of the boron cluster compounds and the coassembly of metallacaborane cobalt bis(dicarbollide), COSAN, with hydrophilic polymers. The research was motivated by the discovery of HIV inhibition by COSAN and its conjugates. Therefore, we decided to study in detail the behavior of boron cluster compounds in water. We demonstrated the amphiphilic character of several boranes and carboranes by the study of surface tension and self-assembly despite the absence of classical amphiphilic topology. The behavior of COSAN showed similarities with classical surfactants, such as SDS, whereas the behavior of smaller clusters with high charge density reminded of hydrotropes or chaotropes. Furthermore, we searched for the most suitable carriers of COSAN for drug delivery. Based on the earlier findings that COSAN interacts with both poly(ethylene oxide), PEO, and poly(2-oxazoline), POX, we prepared nanoparticles by mixing COSAN with block copolymers of various types of POX. Comparing linear and star-like block copolymers, we showed that the polymer architecture has a crucial role in the morphology of nanoparticles. In addition, we proved different selectivity of alkaline cations towards PEO and POX, resulting in the different structures of nanoparticles depending on the present...
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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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Liability for defects in business transactions
Matějíček, Pavel ; Eichlerová, Kateřina (advisor) ; Čech, Petr (referee)
The topic of this thesis is liability for defects in business transactions, or using the terminology of the effective Civil Code, obligations from non-performance. Rights from non- performance are one of the most important legal instruments regarding liability, together with liability for damage and liability for delay, all arising from pecuniary contracts, mainly from purchase contracts and contracts for work. With respect to the elapsed recodification of civil law, obligations arising from non- performance are no longer subject to two codes (in Act No. 40/1964 Coll., Civil Code and in Act No. 513/1991 Coll., Commercial Code), they are now governed only by Act No. 89/2012 Coll., the effective Civil Code. Civil code and its provisions are therefore the main part of this thesis. Moreover, some parts of the thesis contain comparison of the effective Civil Code to the preceding legislation, i.e. the Commercial Code, and to some international treaties as well. The first chapter, which follows right after the preface, contains sources of this thesis. The second chapter deals with the concept of obligations arising from non-performance, compares them to other areas of civil law dealing with liability, and later deals with the concept of commercial obligation. The third chapter talks about the provisions...
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ASSOCIATION BEHAVIOUR OF CARBORANES AND THEIR INTERACTIONS WITH POLYMERS IN SOLUTIONS
Ďorďovič, Vladimír ; Matějíček, Pavel (advisor) ; Cígler, Petr (referee)
This diploma thesis deals with the behavior of cobalt bis(dicarbollide) and its derivatives containing polyethylene oxide linkers in aqueous and salted solution and their interactions with some biocompatible block copolymers. In this study we chose diblock copolymer poly(ethylene oxide)-block-poly(2-ethyl oxazoline), PEO-PEOX, triblock copolymer poly(2- ethyl oxazoline)-block-poly(ethylene oxide)-block-poly(2-ethyl oxazoline), PEOX-PEO- PEOX and starlike polymer 4-arm poly(ethylene oxide)-block-poly(2-methyl oxazoline), 4- arm PEO-PMOX. Solubility and change of hydrodynamic radius of metallacarborane particles depending on the cation of corresponding salt solution was studied. Solubility and size of particles changes depending on counterion of metallacarborane and also on the length and type of PEG linker of carborane compound. In solutions with polymer cobalt bis(dicarbollide) and his conjugates form particles composed of complex polymer/caborane. Adding polymer increase solubility of carborane and in most cases it decreases the size of particles in solution. These systems were studied by means of light scattering, UV-VIS spectroscopy, ITC, NMR and SAXS.
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Interaction of metallacarboranes with biocompatible polymers in solutions
Ďorďovič, Vladimír ; Matějíček, Pavel (advisor) ; Cígler, Petr (referee)
The bachelor thesis deals with the behavior of aqueous solutions of polystyrene- block-poly(ethylene oxide), PS-PEO, and poly(ethylene oxide)-block-poly(2-ethyl oxazoline), PEO-PEOX, and their interaction with sodium 3-cobalt bis(1,2-dicarbollide), NaCoD. The prepared nanoparticles were characterized by static and dynamic light scattering, AFM and cryo-TEM. While PEO-PEOX is molecularly soluble in water, PS- PEO forms micelles with PS core and PEO shell. We determined by dialysis that CoD¯ interacts with both PEO and PEOX segments depending on the salt concentration. Even small amount of NaCoD results in destabilization of PS-PEO micelles. On the other hand, PEO-PEOX mixtures with NaCoD in salted aqueous solutions contain vesicles with radii 69 nm.
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Comicellization of polystyrene-block-poly(acrylic acid) with low-molar-mass surfactants
Paloncýová, Markéta ; Matějíček, Pavel (referee) ; Štěpánek, Miroslav (advisor)
This B.Sc. thesis deals with the study of the effect of low-molar-mass ionic surfactants sodium dodecyl sulfate (SDS) and hexydecyltrimethylammonium bromide (HTAB) on association behavior of the block copolymer polystyrene-b-polyacrylic acid (PS-b-PAA) in alkaline aqueous solutions. Prepared polymeric nanoparticles were characterized by static and dynamic light scattering, transmission electron microscopy and 1 H NMR spectroscopy. It was found that both surfactants interact only with PAA blocks and their presence in the system leads to worsening of the copolymer solubility which manifests itself in the formation of large micellar aggregates and in precipitation of the copolymer-surfactant complexes.
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