|
|
Metal-organic interface for effective charge transfer
Mrhačová, Petra ; Průša, Stanislav (referee) ; Procházka, Pavel (advisor)
This bachelor thesis deals with the analysis of benzene-1,3,5-tricarboxylic acid (TMA) molecules on a silver crystal with (111) surface termination. After the deposition of the molecules on the substrate, a fully protonated layer ( phase) is formed. Further substrate annealing induces a deprotonation process, which leads to the formation of another and phases. The different arrangements of the molecules were studied in ultra-high vacuum conditions by low-energy electron microscope (LEEM), scanning tunneling microscope (STM), and by low-energy electron diffraction (LEED). The application potential of these layers is discussed.
|
|
|
The study of the association behavior of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations.
Šindelka, Karel ; Limpouchová, Zuzana (advisor) ; Slavíček, Petr (referee) ; Vondrášek, Jiří (referee)
Title: The study of the association behaviour of the amphiphilic copolymers in solutions containing low molar compounds by means of computer simulations. Author: Mgr. Karel Šindelka Department: Faculty of Science, Charles University Supervisor: Doc. Ing. Zuzana Limpouchová, Csc. Abstract This doctoral thesis focuses on the study of electrostatic self- and co-assembly in complex polymer solutions containing polyelectrolyte (PE) block copolymers together with surfactants, neutral homopolymers, or oppositely charged PEs using the dissipative particle dynamics (DPD). It was shown that the electro- static self-assembly depends not only on the cooperative interactions of oppo- sitely charged PE chains, but also on the amphiphilicity of PE species or on the polymer block compatibility, among other properties. PEs with incompatible blocks create well-defined core-shell structures, while large ill-defined crew-cut aggregates form from PEs with compatible blocks In non-stoichiometric mixtures of PEs with incompatible blocks, co-assembled nanoparticles are smaller than in stoichiometric mixtures and are charged. The destabilization of larger aggregates depends on how the PE charge surplus is introduced: the effect is strongest when the density of the surplus PE charge on the PE chains is increased and weakest when the...
|
|
|
The study of self-assembly governed by the formation of donor-acceptor complexes
Warzecha, Tomáš ; Starý, Ivo (advisor) ; Betík, Robert (referee)
The study of self-assembly governed by the formation of donor-acceptor complexes This work deals with the preparation of 2-[(3-carboxyphenyl)ethynyl]benzoic acid, which a represents simplified model of monodisperse (p-phenylen)ethynylene oligomers, functionalized by carboxylic groups. Such a dicarboxylic acid was synthesized via Sonogashira coupling and then taken over to a series of diesters with corresponding alcohols. The theoretical part contains concise introduction to nanoscience, self assembly and donor - acceptor (D-A) interactions. The most frequently used synthetic reactions - Sonogashira coupling and Steglich esterification are described. The experimental part deals with the preparation of dimeric dicarboxylic acid and corresponding esters with alcohols containing electronacceptor functional groups. The synthetized compounds were characterized by spectroscopic methods (NMR, MS, IR, UV/VIS) and elemental composition established by HR MS. Melting points were measured for crystalline compounds.
|
|
|
Computer simulations of conformational behavior of block copolymers in selective solvents
Šindelka, Karel ; Limpouchová, Zuzana (advisor) ; Kuldová, Jitka (referee)
The presented bachelor thesis deals with the study of the conformational be- haviour of diblock copolymers in the selective solvent. The polymer solution was modelled using a coarse-grained model and is simulated using dissipative particle dynamics (DPD). An original C-code for DPD simulations together with a new software package for processing of simulation data was developed. Functionality of the code and software were tested for two systems. The first system corre- sponded to a linear homopolymer in a solvent and the scaling laws for homopoly- mer in dilute solution were reproduced. The second system represented diblock copolymers in selective solvents and micellar behaviour simulated with the de- veloped code agreed with simulations by Sheng et al. Then, the self-assembly of long copolymer chains in selective solvents that mimics a block copolymer of poly(methacrylic acid) and poly(ethylene oxide) in aqueous solution at pH 1 was studied for different polymer concentrations. The simulation results provided valuable insight into the studied system and serve as a good starting point for DPD simulations of this system with added surfactants and at different values of pH, where the electrostatic interactions become important.
|
|
|
Self-Assembly in Mixture of Surfactants and Stimuli-Responsive Polymers with Complex Architecture
Bogomolova, Anna ; Filippov, Sergej (advisor) ; Štěpánek, Miroslav (referee) ; Hanyková, Lenka (referee)
Title: Self-assembly in mixture of surfactants and stimuli-responsive polymers with complex architecture Author: Anna Bogomolova Department: Physical and Macromolecular Chemistry Supervisor: PhD. Sergey K. Filippov, IMC AS CR, v.v.i. Supervisor's e-mail address: filippov@imc.cas.cz Abstract: The issue of construction of complex multi-block copolymers is currently one of the most researched areas. It became a logic consequence of the continuous development in polymer chemistry. Nowadays, a great interest is attracted to multi- responsive block copolymers. As a rule, they consist of hydrophilic, hydrophobic and responsive blocks. That responsive block can be either thermo-sensitive or pH-sensitive as well as sensitive to some other external stimuli. In the present work, we will try to cover topic of stimuli-responsive block copolymers and their interactions with different types of surfactants. Understanding of polymer/surfactant interactions can be a crucial step for future modeling of drug/polymer or protein(DNA)/surfactant interactions. There is a great interest in the investigation of polymer-surfactant interactions. However, while the homopolymer-surfactant interactions are characterized well enough, the same interactions for block copolymers are poorly described. The main development in the latter topic...
|
|
|
The D-A and pi-pi interactions and their use in self-assembly
Rejchrtová, Blanka ; Starý, Ivo (advisor) ; Kotora, Martin (referee)
The D-A and π-π Interactions and Their Use in Self-Assembly Due to their well-defined shape, size and properties gold nanoparticles represent an advantageous platform for the study of non-covalent interactions between ligands anchored to their surface both in solution and in monolayers or thin films. The aim of this thesis was the synthesis of ligands for gold nanoparticles bearing an anchoring group at one end and a planar π-electron rich pyrene unit at the other. Six structurally variable ligands were prepared differing in the pyrene substitution pattern and the spacer between the aromatic part and the acetylated thiol function. Furthermore, a synthetic pathway leading to extended π-electron systems (both electron rich and electron poor) such as hexabenzocoronene derivatives and its fragments was explored. The key steps in the synthesis of these compounds are the cyclization reactions of alkynes leading to polycyclic intermediates and their ensuing cyclodehydrogenation (Scholl reaction). All of the prepared ligands and their intermediates were characterized by spectroscopic methods. The structure of the key hexakis(pentafluorosulfanyl-phenyl)benzene was confirmed by single crystal X-ray crystallography. The prepared ligands bearing a pyrene unit were deacetylated and anchored to the surface of...
|
|
|
Influence of Si surface passivation on growth and ordering of nanostructures
Matvija, Peter ; Kocán, Pavel (advisor) ; Rezek, Bohuslav (referee) ; de la Torre, Bruno (referee)
Silicon is currently the most widely used semiconductor material with applications ranging from solar cells and sensors to electronic devices. Surface functionalization of silicon with molecular monolayers can be used to tune properties of the material toward a desired application. However, site-specific adsorption of molecules or molecular patterning on silicon surfaces is a difficult task due to the high reactivity of silicon. In this work, we use scanning tunneling microscopy, ab-initio calculations and kinetic Monte Carlo simulations to study adsorption of organic molecules on a bare and thallium-passivated Si(111) surface. We show that the polarity of molecules has a large impact on bonding of the molecules with the bare surface. We demonstrate that, in comparison with the bare surface, molecules or single-atom adsorbates deposited on the Tl-passivated surface have significantly higher mobility. The increased mobility induces formation of 2D gases on the surface and enables formation of self-assembled molecular structures. We propose a novel method to directly visualize the 2D surface gases and we show that a phase of surface gases containing molecule-bound dipoles can be controlled by a non-homogeneous electric field. 1
|
|
|
Beating Intracellular Bacterial Infections with Polymeric Nanobead-Based Interventions: Development, Structure Characterization, and Analysis
Trousil, Jiří ; Hrubý, Martin (advisor) ; Záruba, Kamil (referee) ; Kročová, Zuzana (referee)
One hundred years after the discovery of antimicrobials and antibiotics, intracellular bacterial pathogens remain a major cause of global morbidity and mortality. This is due to the complex and intricate ability of these pathogens to undergo intracellular replication while evading host cell immune defense. Bacterial agents such as Legionella pneumophila, Francisella tularensis, and Mycobacterium tuberculosis, as the causative agents of Legionnaires' disease, pulmonary tularemia, and tuberculosis (TB), respectively, contribute to this burden. Moreover, these agents are weaponizable pathogens due to their aerosolizability. TB represents a global health problem, although a potentially curative therapy has been available for approximately 50 years; this intracellular disease affects approximately 1 in 3 people worldwide, with over 10 million new cases per year and one death every three minutes. TB can usually be treated with a 6- to 9-month course of combined therapy. The necessity of using a cocktail of anti-TB drugs and the long-term treatment schedules required for conventional therapy, however, result in poor patient compliance; therefore, the risk of treatment failure and relapses is higher. Hence, improved drug delivery strategies for the existing drugs can be exploited to shorten the duration of TB...
|
|
|
Synthesis and characterization of ABA triblock copolymers modified with glucose via thiol - ene click reaction
Hašpl, Adam ; Uchman, Mariusz Marcin (advisor) ; Štěpánek, Miroslav (referee)
The bachelor thesis is focused on method of postpolymerisation modification of two poly(ethylene oxid-b-1,2-butadiene-b-ethylene oxide) amphiphilic block copolymer samples with high content of 1,2-isomer units in inner polybutadiene block by thiolene click. The implemented modification agent was 1-thio-β-D-glucose tetraacetate. The thesis is further focused on methods of copolymer sample characterization before and after modification reaction. Structure and degree of functionalization of vinylic units in polybutadiene block after modification was determined by nuclear magnetic resonance spectroscopy. The dimensions of prepared polymeric particles were studied by static and dynamic light scattering methods. Keywords: ABA triblock copolymers, self-assembly, click reaction, NMR spectroscopy, light scattering
|
|
|
Graphene on SiC as a substrate for molecular self-assembly systems
Černá, Lenka ; Průša, Stanislav (referee) ; Procházka, Pavel (advisor)
This bachelor thesis deals with the fabrication and characterization of metal-organic frameworks formed by self-assembly mechanism of metal atoms (Fe) and organic molecules (tetracyanoquinodimethane, TCNQ) on a graphene surface. The fabrication of self-assembled structures has been performed on epitaxial graphene on SiC(0001) substrate. The deposition of metal-organic networks, as well as subsequent surface characterization by low-energy electron microscopy (LEEM) scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), were performed under ultra-high vacuum conditions.
|
guest ::
