Synthesis and pH-responsive dissociation of framboidal ABC triblock copolymer vesicles in aqueous solution

A series of pH-responsive all-methacrylic ABC triblock copolymer vesicles were prepared from precursor diblock copolymer vesicles via RAFT seeded emulsion polymerisation. Microphase separation between the two hydrophobic membrane-forming B and C blocks produced a distinctive framboidal morphology, for which the mean globule size can be tuned by adjusting the triblock copolymer composition. These vesicles remain intact at neutral pH, but undergo irreversible dissociation on addition of acid as a result of protonation of the tertiary amine groups located within the third block. Small-angle X-ray scattering (SAXS) was utilised to characterise the morphologies formed at pH 8 and pH 3. According to time-resolved SAXS studies, the acid-induced dissociation of these pH-responsive framboidal vesicles involves appreciable membrane swelling within 50 ms and is complete

Complementary light scattering and synchrotron small-angle X-ray scattering studies of the micelle-to-unimer transition of polysulfobetaines

YesAB and ABA di- and triblock copolymers where A is the hydrophilic poly(oligoethylene glycol methacrylate) (POEGMA) block and B is a thermo-responsive sulfobetaine block [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide (PDMAPS) were synthesised by aqueous RAFT polymerisation with narrow dispersity (ĐM ≤ 1.22), as judged by aqueous SEC analysis. The di- and triblock copolymers self-assembled in salt-free water to form micelles with a PDMAPS core and the self-assembly of these polymers was explored by SLS and TEM analysis. The micelles were shown, by DLS analysis, to undergo a micelle-to-unimer transition at a critical temperature, which was dependent upon the length of the POEGMA block. Increasing the length of the third, POEGMA, block decreased the temperature at which the micelle-to-unimer transition occurred as a result of the increased hydrophilicity of the polymer. The dissociation of the micelles was further studied by SLS and synchrotron SAXS. SAXS analysis revealed that the micelle dissociation began at temperatures below that indicated by DLS analysis and that both micelles and unimers coexist. This highlights the importance of using multiple complementary techniques in the analysis of self-assembled structures. In addition the micelle-to-unimer morphology transition was employed to encapsulate and release a hydrophobic dye, Nile Red, as shown by fluorescence spectroscopy.Engineering and Physical Sciences Research Council (EPSRC), University of Warwic

Coherent Random Lasing Realized in Polymer Vesicles

We have demonstrated the realization of a coherent vesicle random lasing (VRL) from the dye doped azobenzene polymer vesicles self-assembled in the tetrahydrofuran-water system, which contains a double-walled structure: a hydrophilic and hydrophobic part. The effect of the dye and azobenzene polymer concentration on the threshold of random laser has been researched. The threshold of random laser decreases with an increase in the concentration of the pyrromethene 597 (PM597) laser and azobenzene polymer. Moreover, the scattering of small size group vesicles is attributed to providing a loop to boost the coherent random laser through the Fourier transform analysis. Due to the vesicles having the similar structure with the cell, the generation of coherent random lasers from vesicles expand random lasers to the biomedicine filed

Influence of pH-Responsive Monomer Content on the Behavior of Di-Block Copolymers in Solution and as Stabilizers of Pickering Latex Particle Emulsifiers

In this study, diblock copolymers poly(methyl methacrylate)—block—poly (2-dimethylaminoethyl methacrylate) (pMMA-b-pDMAEMA) are investigated for the steric stabilization of latex particles and the subsequent use of these latex particles as Pickering emulsifiers. Solution properties of the diblock copolymers highlight that the pDMAEMA block length influences the critical micelle concentration (CMC) and micelle hydrodynamic diameter in response to changes in pH and the pKₐ. The block length can also be used as a way to control the particle size of sterically stabilized polystyrene latex particles prepared via emulsion polymerization. The suspension properties of these latex particles are also presented. Emulsion studies using these latex particles as emulsifiers show that both continuous phase pH and electrolyte concentration affect emulsion stability to coalescence. At high pH, stable emulsions are formed due to the affinity of the particles to the interface. At low pH, protonation of the amine groups reduces the affinity and thus droplet coalescence is observed. Increasing the electrolyte concentration improves emulsion stability, but causes an increase in droplet size due to adsorption of flocculated/aggregated particles. Finally, it is shown that these latex particles can be used in conjunction with membrane emulsification techniques to produce emulsions with low polydispersity

4x4 Czech Snowboard Cup

This thesis is divided into theoretical and practical part. The theoretical part deals with general characteristics of sports competitions, their history, classification, funding, as well as introduces freestyle snowboarding in general, its disciplines, history, and the Association of Czech Snowboarding. In the practical part I analyze the profit and loss statements, comparing individual budgets, revenues, expenses and profits as well as compiling a horizontal trend analysis, SWOT analysis, benchmarking analysis of competing domestic and foreign firms and correlation analysis with the level of professional snowboarding in our country. In the end I present reached results and suggests many improvements to the current situation

Analysis of Roma integration in the Czech Republic using the theory of social construction of target populations

The master thesis deals with public policies in the area of Roma minority inclusion in the modern history of the Czech Republic after 1989. The main objective of the thesis is to identify, by applying the theory of social construction of target populations, the form of state intervention in solviing the exclusion of the Roma minority from society. And then to find out what influence the social construction of the Roma and their political possibilities play here. The research consists in analysing and identifying the different elements of the theory in the following order: 1. Analysis of public policies for Roma integration; 2. Analysis of the social construction of the Roma; 3. Analysis of the political power of Roma. The first step towards achieving the aim of the thesis is to reveal the nature of the policy design of Roma integration. In this step, I will analyse a convolute of public policy documents, which includes international legal conventions, domestic minority laws and strategic documents. In the next step, I will focus on the social image of the Roma, the form of which, according to the social construction theory of target populations, plays an undeniable role in the formulation of public policies and the behaviour of elected officials. The last main effort to fulfil the aim of the thesis..

Analysis of Roma integration in the Czech Republic using the theory of social construction of target populations

The master thesis deals with public policies in the area of Roma minority inclusion in the modern history of the Czech Republic after 1989. The main objective of the thesis is to identify, by applying the theory of social construction of target populations, the form of state intervention in solviing the exclusion of the Roma minority from society. And then to find out what influence the social construction of the Roma and their political possibilities play here. The research consists in analysing and identifying the different elements of the theory in the following order: 1. Analysis of public policies for Roma integration; 2. Analysis of the social construction of the Roma; 3. Analysis of the political power of Roma. The first step towards achieving the aim of the thesis is to reveal the nature of the policy design of Roma integration. In this step, I will analyse a convolute of public policy documents, which includes international legal conventions, domestic minority laws and strategic documents. In the next step, I will focus on the social image of the Roma, the form of which, according to the social construction theory of target populations, plays an undeniable role in the formulation of public policies and the behaviour of elected officials. The last main effort to fulfil the aim of the thesis...Předkládaná diplomová práce se zabývá veřejnými politikami v oblasti začleňování romské menšiny v novodobé historii České republiky po roce 1989. Stěžejním cílem práce je identifikovat pomocí aplikace teorie sociální konstrukce cílových populací podobu státní intervence v řešení vyloučení romské menšiny ze společnosti. A posléze zjistit, jaký vliv zde hraje sociální konstruování Romů a jejich politické možnosti. Výzkum spočívá v analýze a identifikaci jednotlivých prvků teorie v tomto pořadí: 1. Analýza veřejných politik romské integrace; 2. Analýza sociálního konstruování Romů; 3. Analýza politické moci Romů. Prvním krokem k naplnění cíle práce je odhalení povahy policy desigu romské integrace. V tomto kroku budu analyzovat konvolut veřejně politických dokumentů, do kterého patří mezinárodněprávní úmluvy, české menšinové zákony a strategické dokumenty. V dalším kroku se věnuji společenskému obrazu Romů, jehož podoba podle teorie sociální konstrukce cílových populací hraje neoddiskutovatelnou roli při formulaci veřejných politik a chování volených úředníků. Posledním krokem k naplnění cíle práce je zmapování politických možnosti Romů a jejich dopadu na (ne)prosazení svých zájmů. Výsledné poznatky a jejich následná syntéza přinesou odpověď na výzkumné otázky a určí typ cílové populace romské...Katedra veřejné a sociální politikyDepartment of Public and Social PolicyFaculty of Social SciencesFakulta sociálních vě