Die effektive Ladung eines Polyelektrolyten in Abhängigkeit der Polymerkonzentration und Ionenstärke

Die Ladungsdichte eines Polyelektrolyten bestimmt im Wesentlichen das spezielle physikochemische Verhalten in Lösung und stellt einen der wichtigsten Parameter bei deren Anwendung dar. Folglich ist ein quantitatives Verständis über die effektive Ladung unabdingbar und stellt nach wie vor einen Schwerpunkt aktueller Polymerforschungen dar. Allgemein anerkannt ist die Tatsache, dass die effektive Ladungsdichte in allen Fällen niedriger ist, als es die chemische Struktur vorgibt. Die vorliegende Arbeit befasst sich mit der quantitativen Bestimmung der effektiven Ladung eines linearen, anionischen Polyelektrolyts in einem organischen Lösungsmittel. Zu diesem Zweck wurde ein Polymer mit geschützten Carboxylatgruppen synthetisiert, das eine nachträgliche quantitative Anpassung der Ladungsdichte durch Verseifung eines Esters erlaubt. Der auf diesemWeg synthetisierte Polyelektrolyt besitzt eine theoretische Ladungsdichte von 20% und wurde mit Lichtstreutechniken, Fluoreszenzkorrelationsspektroskopie und elektrophoretischen Methoden untersucht um anschließend aus den erhaltenen Daten, unter Verwendung verschiedener Theorien, die effektive Ladung in Abhängigkeit der Polymer- und Salzkonzentration zu bestimmen. Die Ergebnisse liefern, in Abhängigkeit der verwendeten Theorie, eine konstante oder von den äußeren Parametern abhängige Ladungsdichte, die immer deutlich unter der theoretisch möglichen liegt.

The dynamics of ultra-thin polymer films in different confinements studied by resonance enhanced dynamic light scattering

Die Kontroverse über den Glasübergang im Nanometerbereich, z. B. die Glas¬über¬gangs-temperatur Tg von dünnen Polymerfilmen, ist nicht vollständig abgeschlossen. Das dynamische Verhalten auf der Nanoskala ist stark von den einschränkenden Bedingungen abhängig, die auf die Probe wirken. Dünne Polymerfilme sind ideale Systeme um die Dynamik von Polymerketten unter der Einwirkung von Randbedingungen zu untersuchen, wie ich sie in dieser Arbeit variiert habe, um Einblick in dieses Problem zu erhalten.rnrnResonanzverstärkte dynamische Lichtstreuung ist eine Methode, frei von z.B. Fluoreszenzmarkern, die genutzt werden kann um in dünnen Polymerfilmen dynamische Phänomene

Control over microstructure evolution and device performance in solution processable organic field-effect transistors

Die Arbeit beschäftigt sich mit der Kontrolle von Selbstorganisation und Mikrostruktur von organischen Halbleitern und deren Einsatz in OFETs. In Kapiteln 3, 4 und 5 eine neue Lösungsmittel-basierte Verabeitungsmethode, genannt als Lösungsmitteldampfdiffusion, ist konzipiert, um die Selbstorganisation von Halbleitermolekülen auf der Oberfläche zu steuern. Diese Methode als wirkungsvolles Werkzeug erlaubt eine genaue Kontrolle über die Mikrostruktur, wie in Kapitel 3 am Beispiel einer D-A Dyad bestehend aus Hexa-peri-hexabenzocoronene (HBC) als Donor und Perylene Diimide (PDI) als Akzeptor beweisen. Die Kombination aus Oberflächenmodifikation und Lösungsmitteldampf kann die Entnetzungseffekte ausgleichen, so dass die gewüschte Mikrostruktur und molekulare Organisation auf der Oberfläche erreicht werden kann. In Kapiteln 4 und 5 wurde diese Methode eingesetzt, um die Selbstorganisation von Dithieno[2, 3-d;2’, 3’-d’] benzo[1,2-b;4,5-b’]dithiophene (DTBDT) und Cyclopentadithiophene -benzothiadiazole copolymer (CDT-BTZ) Copolymer zu steuern. Die Ergebnisse könnten weitere Studien stimulieren und werfen Licht aus andere leistungsfaähige konjugierte Polymere. rnIn Kapiteln 6 und 7 Monolagen und deren anschlieβende Mikrostruktur von zwei konjugierten Polymeren, Poly (2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) PBTTT und Poly{[N,N ′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis (dicarboximide)-2,6-diyl]-alt-5,5′- (2,2′-bithiophene)}, P(NDI2OD-T2)) wurden auf steife Oberflächen mittels Tauchbeschichtung aufgebracht. Da sist das erste Mal, dass es gelungen ist, Polymer Monolagen aus der Lösung aufzubringen. Dieser Ansatz kann weiter auf eine breite Reihe von anderen konjugierten Polymeren ausgeweitet werden.rnIn Kapitel 8 wurden PDI-CN2 Filme erfolgreich von Monolagen zu Bi- und Tri-Schichten auf Oberflächen aufgebracht, die unterschiedliche Rauigkeiten besitzen. Für das erste Mal, wurde der Einfluss der Rauigkeit auf Lösungsmittel-verarbeitete dünne Schichten klar beschrieben.rn

Analysis and numerical solution of the Peterlin viscoelastic model

Liquids and gasses form a vital part of nature. Many of these are complex fluids with non-Newtonian behaviour. We introduce a mathematical model describing the unsteady motion of an incompressible polymeric fluid. Each polymer molecule is treated as two beads connected by a spring. For the nonlinear spring force it is not possible to obtain a closed system of equations, unless we approximate the force law. The Peterlin approximation replaces the length of the spring by the length of the average spring. Consequently, the macroscopic dumbbell-based model for dilute polymer solutions is obtained. The model consists of the conservation of mass and momentum and time evolution of the symmetric positive definite conformation tensor, where the diffusive effects are taken into account. In two space dimensions we prove global in time existence of weak solutions. Assuming more regular data we show higher regularity and consequently uniqueness of the weak solution. For the Oseen-type Peterlin model we propose a linear pressure-stabilized characteristics finite element scheme. We derive the corresponding error estimates and we prove, for linear finite elements, the optimal first order accuracy. Theoretical error of the pressure-stabilized characteristic finite element scheme is confirmed by a series of numerical experiments.

Statistical mechanics of polymer models: rigorous results and applications

Monomer-dimer models are amongst the models in statistical mechanics which found application in many areas of science, ranging from biology to social sciences. This model describes a many-body system in which monoatomic and diatomic particles subject to hard-core interactions get deposited on a graph. In our work we provide an extension of this model to higher-order particles. The aim of our work is threefold: first we study the thermodynamic properties of the newly introduced model. We solve analytically some regular cases and find that, differently from the original, our extension admits phase transitions. Then we tackle the inverse problem, both from an analytical and numerical perspective. Finally we propose an application to aggregation phenomena in virtual messaging services.

Excited state properties of formamide in water solution: An ab initio study

We present ab initio quantum calculation of the optical properties of formamide in vapor phase and in water solution. We employ time dependent density functional theory for the isolated molecule and many-body perturbation theory methods for the system in solution. An average over several molecular dynamics snapshots is performed to take into account the disorder of the liquid. We find that the excited stateproperties of the gas-phase formamide are strongly modified by the presence of the water solvent: the geometry of the molecule is distorted and the electronic and optical properties are severely modified. The important interaction among the formamide and the water molecules forces us to use fully quantum methods for the calculation of the excited stateproperties of this system. The excitonic wave function is localized both on the solute and on part of the solvent.

Supported Cu(II) polymer catalysts for aqueous phenol oxidation

Supported Cu(II) polymer catalysts were used for the catalytic oxidation of phenol at 30 degrees C and atmospheric pressure using air and H(2)O(2) as oxidants. Heterogenisation of homogeneous Cu(II) catalysts was achieved by adsorption of Cu(II) salts onto polymeric matrices (poly(4-vinylpyridine), Chitosan). The catalytic active sites were represented by Cu(II) ions and showed to conserve their oxidative activity in heterogeneous catalysis as well as in homogeneous systems. The catalytic deactivation was evaluated by quantifying released Cu(II) ions in solution during oxidation, from where Cu-PVP(25) showed the best leaching levels no more than 5 mg L(-1). Results also indicated that Cu-PVP(25) had a catalytic activity (56% of phenol conversion when initial Cu(II) catalytic content was 200 mg L(Reaction)(-1)) comparable to that of commercial catalysts (59% of phenol conversion). Finally, the balance between activity and copper leaching was better represented by Cu-PVP(25) due to the heterogeneous catalytic activity had 86% performance in the heterogeneous phase, and the rest on the homogeneous phase, while Cu-PVP(2) had 59% and CuO/gamma-Al(2)O(3) 68%.

Geocenter coordinates estimated from GNSS data as viewed by perturbation theory

Time series of geocenter coordinates were determined with data of two global navigation satellite systems (GNSSs), namely the U.S. GPS (Global Positioning System) and the Russian GLONASS (Global’naya Nawigatsionnaya Sputnikowaya Sistema). The data was recorded in the years 2008–2011 by a global network of 92 permanently observing GPS/GLONASS receivers. Two types of daily solutions were generated independently for each GNSS, one including the estimation of geocenter coordinates and one without these parameters. A fair agreement for GPS and GLONASS was found in the geocenter x- and y-coordinate series. Our tests, however, clearly reveal artifacts in the z-component determined with the GLONASS data. Large periodic excursions in the GLONASS geocenter z-coordinates of about 40 cm peak-to-peak are related to the maximum elevation angles of the Sun above/below the orbital planes of the satellite system and thus have a period of about 4 months (third of a year). A detailed analysis revealed that the artifacts are almost uniquely governed by the differences of the estimates of direct solar radiation pressure (SRP) in the two solution series (with and without geocenter estimation). A simple formula is derived, describing the relation between the geocenter z-coordinate and the corresponding parameter of the SRP. The effect can be explained by first-order perturbation theory of celestial mechanics. The theory also predicts a heavy impact on the GNSS-derived geocenter if once-per-revolution SRP parameters are estimated in the direction of the satellite’s solar panel axis. Specific experiments using GPS observations revealed that this is indeed the case. Although the main focus of this article is on GNSS, the theory developed is applicable to all satellite observing techniques. We applied the theory to satellite laser ranging (SLR) solutions using LAGEOS. It turns out that the correlation between geocenter and SRP parameters is not a critical issue for the SLR solutions. The reasons are threefold: The direct SRP is about a factor of 30–40 smaller for typical geodetic SLR satellites than for GNSS satellites, allowing it in most cases to not solve for SRP parameters (ruling out the correlation between these parameters and the geocenter coordinates); the orbital arc length of 7 days (which is typically used in SLR analysis) contains more than 50 revolutions of the LAGEOS satellites as compared to about two revolutions of GNSS satellites for the daily arcs used in GNSS analysis; the orbit geometry is not as critical for LAGEOS as for GNSS satellites, because the elevation angle of the Sun w.r.t. the orbital plane is usually significantly changing over 7 days.

Outline of a theory of efficient teams in Sport.

Introduction So far, social psychology in sport has preliminary focused on team cohesion, and many studies and meta-analyses tried to demonstrate a relation between cohesiveness of a team and its performance. How a team really co-operates and how the individual actions are integrated towards a team action is a question that has received relatively little attention in research. This may, at least in part, be due to a lack of a theoretical framework for collective actions, a dearth that has only recently begun to challenge sport psychologists. Objectives In this presentation a framework for a comprehensive theory of teams in sport is outlined and its potential to integrate research in the domain of team performance and, more specifically, the following presentations, is put up for discussion. Method Based on a model developed by von Cranach, Ochsenbein and Valach (1986), teams are considered to be information processing organisms, and team actions need to be investigated on two levels: the individual team member and the group as an entity. Elements to be considered are the task, the social structure, the information processing structure and the execution structure. Obviously, different task require different social structures, communication processes and co-ordination of individual movements. Especially in rapid interactive sports planning and execution of movements based on feedback loops are not possible. Deliberate planning may be a solution mainly for offensive actions, whereas defensive actions have to adjust to the opponent team's actions. Consequently, mental representations must be developed to allow a feed-forward regulation of team member's actions. Results and Conclusions Some preliminary findings based on this conceptual framework as well as further consequences for empirical investigations will be presented. References Cranach, M.v., Ochsenbein, G. & Valach, L. (1986). The group as a self-active system: Outline of a theory of group action. European Journal of Social Psychology, 16, 193-229.

Territorial Cohesion through Spatial Policies: An Analysis with Cultural Theory and Clumsy Solutions

The European Territorial Cohesion Policy has been the subject of numerous debates in recent years. Most contributions focus on understanding the term itself and figuring out what is behind it, or arguing for or against a stronger formal competence of the European Union in this field. This article will leave out these aspects and pay attention to (undefined and legally non-binding) conceptual elements of territorial cohesion, focusing on the challenge of linking it within spatial policies and organising the relations. Therefore, the theoretical approach of Cultural Theory and its concept of clumsy solution are applied to overcome the dilemma of typical dichotomies by adding a third and a fourth (but not a fifth) perspective. In doing so, normative contradictions between different rational approaches can be revealed, explained and approached with the concept of ‘clumsy solutions’. This contribution aims at discussing how this theoretical approach helps us explain and frame a coalition between the Territorial Cohesion Policy and spatial policies. This approach contributes to finding the best way of linking and organising policies, although the solution might be clumsy according to the different rationalities involved.

Constraints on the effective fluid theory of stationary branes

We develop further the effective fluid theory of stationary branes. This formalism applies to stationary blackfolds as well as to other equilibrium brane systems at finite temperature. The effective theory is described by a Lagrangian containing the information about the elastic dynamics of the brane embedding as well as the hydrodynamics of the effective fluid living on the brane. The Lagrangian is corrected order-by-order in a derivative expansion, where we take into account the dipole moment of the brane which encompasses finite-thickness corrections, including transverse spin. We describe how to extract the thermodynamics from the Lagrangian and we obtain constraints on the higher-derivative terms with one and two derivatives. These constraints follow by comparing the brane thermodynamics with the conserved currents associated with background Killing vector fields. In particular, we fix uniquely the one- and two-derivative terms describing the coupling of the transverse spin to the background space-time. Finally, we apply our formalism to two blackfold examples, the black tori and charged black rings and compare the latter to a numerically generated solution.

Reaction of Copper(II) Chloroacetate with Pyrazole. Synthesis of a One-Dimensional Coordination Polymer and Unexpected Dehydrochlorination Reaction

The reaction of copper(II) chloroacetate (1d) with pyrazole (Hpz) mainly yielded the mononuclear compound [Cu(μ-ClCH2COO)2(Hpz)2] (2m), which self-assembled generating a one-dimensional coordination polymer. Moreover, the concomitant isolation of the tetranuclear [{Cu2(μ-pz)(μ-OCH2COO)(Hpz)(MeOH)}2(μ-ClCH2COO)2] (3t) and hexanuclear [{Cu3(μ3-OH)(μ-pz)3(Hpz)2}2(μ-ClCH2COO)2](Cl)2 (4h) species evidenced the occurrence of a peculiar, previously unreported, dehydrochlorination reaction and the formation of the trinuclear triangular moiety [Cu3(μ3-OH)(μ-pz)3]. Theoretical calculations based on density functional theory including solvation effects indicate a possible pathway for the formation of 3t. Interestingly, besides the energy minimum corresponding to 3t, a further relative energy minimum is found for a species which can be considered a possible reaction intermediate.

The Entrepreneurial Theory of the Firm and the Theory of the Entrepreneurial Firm

The entrepreneurial theory of the firm argues that entrepreneurship, properly understood, is a crucial but neglected element in explaining the nature and boundaries of the firm. By contrast, the theory of the entrepreneurial firm presumably seeks not to understand the nature and boundaries of "the firm" in general but rather to understand a particular type of firm: one that is entrepreneurial. This paper is an attempt to reconcile the two. After briefly delving for the concept of entrepreneurship in the work of Schumpeter, Kirzner, and (especially) Knight, the paper makes the case for the entrepreneurial theory of the firm. In such a theory, the firm exists as the solution to a coordination problem in a world of change and uncertainty, including Knightian or structural uncertainty. Taking a historical or developmental perspective, the paper then examines the changing nature of the entrepreneurial coordination problem over the life-cycle. In this formulation, "the entrepreneurial firm" is a nascent firm or proto-firm facing a problem of coordinating systemic change in economic capabilities. Lacking (by definition) adequate guidance from existing systems of rules of conduct embedded in markets or organizations, the entrepreneurial firm typically relies on a form of organization Max Weber called charismatic authority. In the end, although there is no such thing as a non-entrepreneurial firm, firms that must solve coordination problems in a world of novelty and systemic change ("entrepreneurial firms") are perhaps the purest case of the entrepreneurial theory of the firm.

The Making of Optimal and Consistent Policy: An Implementation Theory Framework for Monetary Policy

This paper shows that optimal policy and consistent policy outcomes require the use of control-theory and game-theory solution techniques. While optimal policy and consistent policy often produce different outcomes even in a one-period model, we analyze consistent policy and its outcome in a simple model, finding that the cause of the inconsistency with optimal policy traces to inconsistent targets in the social loss function. As a result, the social loss function cannot serve as a direct loss function for the central bank. Accordingly, we employ implementation theory to design a central bank loss function (mechanism design) with consistent targets, while the social loss function serves as a social welfare criterion. That is, with the correct mechanism design for the central bank loss function, optimal policy and consistent policy become identical. In other words, optimal policy proves implementable (consistent).

(Table 2) Stratigraphic position of midpoints of reddish and beige layers of lithologic cycles in the Loulja-A Section and their astronomical ages after tuning to the ETP and Summer Insolation Curves of the La2004 solution

An integrated high-resolution stratigraphy and orbital tuning is presented for the Loulja sections located in the Bou Regreg area on the Atlantic side of Morocco. The sections constitute the upward continuation of the upper Messinian Ain el Beida section and contain a well-exposed, continuous record of the interval straddling the Miocene-Pliocene (M-P) boundary. The older Loulja-A section, which covers the interval from ~5.59 to 5.12 Ma, reveals a dominantly precession-controlled color cyclicity that allows for a straightforward orbital tuning of the boundary interval and for detailed cyclostratigraphic correlations to the Mediterranean; the high-resolution and high-quality benthic isotope record allows us to trace the dominantly obliquity-controlled glacial history. Our results reveal that the M-P boundary coincides with a minor, partly precession-related shift to lighter "interglacial" values in d18O. This shift and hence the M-P boundary may not correlate with isotope stage TG5, as previously thought, but with an extra (weak) obliquity-controlled cycle between TG7 and TG5. Consequently, the M-P boundary and basal Pliocene flooding of the Mediterranean following the Messinian salinity crisis are not associated with a major deglaciation and glacio-eustatic sea level rise, indicating that other factors, such as tectonics, must have played a fundamental role. On the other hand, the onset of the Upper Evaporites in the Mediterranean marked by hyposaline conditions coincides with the major deglaciation step between marine isotope stage TG12 and TG11, suggesting that the associated sea level rise is at least partly responsible for the apparent onset of intermittently restricted marine conditions following the main desiccation phase. Finally, the Loulja-A section would represent an excellent auxiliary boundary stratotype for the M-P boundary as formally defined at the base of the Trubi marls in the Eraclea Minoa section on Sicily.