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Dept. Chemistry-Biology-Geology (SBG) - Organic and Polymer Chemistry

Mostrando recursos 161 - 180 de 455

  1. Kwantificering van de accuratesse in evenwichtsberekeningen: Monte Carlo studie van de foutenpropagatie bij de potentiometrische bepaling van stabiliteitsconstanten

    Guedens, Wanda
    Het onderzoek waarover in dit werk gerapporteerd wordt, concentreert zich op het gebruik van numerieke methoden voor de studie van de foutenpropagatie in diverse toepassingen en in het bijzonder in evenwichtsberekeningen. In het eerste gedeelte van het proefschrift worden volumetrische, calorimetrische en kinetische data geanalyseerd, waarbij we aantonen hoe de techniek van linearisering toelaat om benaderende waarden te vinden voor de fout op relatief ingewikkelde functies f van onnauwkeurig gekende grootheden x1 , ... , x,, . In het tweede gedeelte worden geautomatiseerde potentiometrische experimenten gedetailleerd besproken. In het laatste deel maken we met behulp van de ontwikkelde MatLab™ programmatuur...

  2. Combined quantitative NMR imaging and relaxometry on polymer materials:a fundamental study of rubbers and water uptake in polyamide 46

    POLLARIS, Anne

  3. The polymerisation behaviour of p-quinodimethane systems: verification of radical and anionic mechanisms in the Sulfinyl and the Gilch route

    HONTIS, Lieve

  4. Highly sensitive spectroscopic study of sub-bandgap absorption phenomena in organic thin film solar cells

    Goris, Ludwig

  5. Synthesis, characterisation and application in electronic devices of low band gap materials based on thiophene derivatives

    HENCKENS, Anja
    Recent years have seen the increased use of organic materials for electronic applications as photovoltaic cells and field-effect transistors (FETs). Such applications require the use of conjugated polymers with a sufficiently high quality, purity and molecular weight (Mw > 30 000). This dissertation deals with the search for possible synthetic routes leading to low band gap (LBG) materials, conjugated polymers with a small energy gap between the valence and conduction band. Those materials show interesting properties which make them extremely attractive for applications in plastic electronics. The processability of these materials here is very important. This can be obtained either...

  6. Phenol-formaldehyde resins: a quantitaive NMR study of molecular structure and molecular dynamics

    OTTENBOURGS, Benjamin

  7. Non-alternant cyclo-penta fused polycyclic aromatic hydrocarbons: Efficient structural elements to achieve n-type characteristics in conjugated polymers

    Palmaerts, Arne
    The aim of the research presented in this dissertation is the design and development of a new class of n-type conjugated polymers. This aim is motivated by the expectation that such a class of materials potentially can Chapter 2 describes our search for and discovery of a novel class of n-type conjugated polymers. The synthesis and characterization of the first representative of this class of polymers, i.e. poly(fluoranthene vinylene) PFV, is presented. In chapter 3, side chains are attached to the fluoranthene groups present in the PFV backbone. The major objective for this functionalization with alkyl groups is to improve...

  8. Plasma deposition of conjugated polymers at atmospheric pressure

    Dams, Roel
    Conjugated polymers possess some unique properties, which make them useful for a lot of applications. However, their rigid structure makes them insoluble and difficult to process. Today, (electro)chemically produced conjugated polymers can be synthesized in batch processes for applications with high added value. In-line processing is still difficult. Therefore, plasma technology at atmospheric pressure is presented in this thesis as an alternative synthesis method. Besides the possibility for in-line deposition directly onto the substrate, there is the advantage of dry processing. No solvents are needed, which is an important environmental benefit. ln this thesis, two objectives were postulated: • Proof...

  9. Physico-chemical, electrical and optical properties of regiorandom and regioregular MDMO-PPV

    MUNTERS, Tom
    Since the beginning of the nineties precursor routes towards semiconducting polymers are examined at the ‘Instituut voor Materiaal Onderzoek’ (IMO) part of the ‘Limburgs Universitair Centrum’ (LUC). Besides the successful development of a new synthetic precursor route, the so-called sulfinyl route, chemical and physical characterization techniques are used to better understand the structure-property relation. A widely used ‘workhorse’ conjugated polymer, MDMO-PPV (a PPV derivative) can be synthesized via this sulfinyl route. Two chemical defects related to asymmetrically substituted PPV-derivatives, such as the ‘workhorse’ material MDMO-PPV can be distinguished: defects related with the position of the side-chains (regioregularity) and defects related...

  10. Development of a molecular spaceframe. Study towards the synthesis of molecular building blocks for this new material concept.

    Van Dijk, Joachim
    There is a permanent need for the development of new concepts and routes towards new and advanced material systems. Sometimes the macroscopic world can be used to inspire us for such new concepts. Dr. Ing. Roelof Marissen (DSM Research and Delft University of Technology, The Netherlands) suggested in 1998 investigating whether the principles of macroscopic mechanical engineering could be translated to molecular scale, provided that sufficient analogy was present between the type of molecules and the type of macroscopic structure. A very efficient macroscopic structure for mechanical strength and low density is a space frame. Space frames consist of rods,...

  11. Identification and quantification of structural defects in 13C- and 2H-labeled Gilch and sulphinyl MDMO-PPV - A correlation between chemical structure and molecular dynamics and ordering by modern NMR spectroscopy

    ROEX, Hilde
    A thorough knowledge of the chemical structure – physical properties relationship is the main objective of this research project. Understanding the factors influencing the opto-electronic properties especially the synthetic procedures used, may provide the means to enhance the efficiency of the opto-electronic devices. In chapter two, the basic principles of nuclear magnetic resonance spectroscopy (NMR) are described. Throughout this work, NMR spectroscopy has proven to be a powerful and indispensable tool, not only to elucidate the polymer structure, but also to provide insight into the molecular ordering and dynamics of polymer chains. The type and amount of structural defects present...

  12. Electrical Characterisation of 2,5-Substituted Poly (p-Phenylene Vinylene) Derivates and their Application in Organic Bulk Heterojunction Solar Cells

    BRESELGE, Martin

  13. Design, Synthesis and Evaluation of Functionalized Poly (p-Phenylene Vinylene) derivates: From Existing Structures to Novel Materials

    VAN SEVEREN, Ineke
    In Chapter one, a concise description of conjugated polymers is given. Conjugated materials combine the electronic and optical properties of semiconductors with the processability and mechanical characteristics of polymers and with the readily-tailored properties of functional organic molecules. In particular the potential use of these materials in light-emitting diodes, photovoltaic cells and other opto-electronic devices has motivated the development of synthesis and processing methods of conjugated polymer materials with unique properties. Within the wide range of different classes of conjugated polymers, poly(para-phenylene vinylene) (PPV) and its derivatives are known as promising materials. Hence, we chose this existing backbone structure for...

  14. Synthesis and Characterisation of Polar PPV Derivatives through the Sulfinyl Precursor Route

    MOTMANS, Filip
    In Chapter 1 a general introduction on conjugated polymers and more specifically on poly- (para-phenylene vinylene) or PPV and its derivatives is presented. Different synthetic routes, all with their main properties and advantages, are described. Possible applications for these materials, such as light emitting diodes, photovoltaic cells and (bio)sensors are mentioned as well. The need for functional conjugated polymers is also expressed in the aim of the thesis. Chapter 2 deals with the synthesis and characterisation of some functional sulfinyl precursor polymers. The four different functional groups are a triethylene glycol derived chain, an alcohol function, an ester and a...

  15. Study of the Dithiocarbamate Route as a viable synthetic route towards Poly(Thienylene Vinylene) Derivatives

    BANISHOEIB, Fateme
    Poly(arylenevinylene)s are considered to be promising candidates for electrical and/or optical materials. Such applications require the use of conjugated polymers with a sufficiently high quality, purity, and molecular weight (Mw >30000). This dissertation deals with the study of the Dithiocarbamate precursor route as a possible synthetic route for the synthesis of low band gap (LBG) materials. Those materials show interesting properties which make them extremely attractive for application in plastic electronics. The processability becomes then a very important issue. This can be obtained either by introducing long side chains or by the use of a precursor route. In this dissertation...

  16. Spectroscopy, electrochemistry and spectro-electrochemistry of PPV and PTV derivates; the effect of backbone structure and side chain polarity on the optoelectronic properties of conjugated polymers

    FOURIER, Sofie

  17. New poly(arylene vinylene) derivatives via the sulphinyl precursor route

    Gilissen, Stijn
    This thesis deals with the synthesis and characterisation of some new conductive polymers. Within this large family of polymers the poly(arylene vinylene) derivatives were selected. In this work these derivatives are synthesised via the sulphinyl precursor route. The results presented unambiguously demonstrate that this synthetic pathway currently is the most versatile way to synthesise these derivatives. Ever since electroluminescence was first discovered in PPV (anno 1989), the search for the most effective synthetic pathway was on and a lot of new derivatives have seen the daylight. More recently, conductive polymers have also been used in other applications and in time...

  18. Looking at molecular multidomain behaviour of polymer systems through NMR-relaxometry

    Storme, Liesbet
    A general introduction into the basic principles of NMR spectroscopy is represented in Chapter 1, followed by a description of relaxometry. In Chapter 2, NMR relaxometry is utilised in the liquid state to examine the gelation mechanism of syndiotactic poly(methyl methacrylate) (sPMMA). By means of a spin-spin relaxation time study, components with a different molecular mobility and their accompanying fractions reveals a better understanding of the two step gelation mechanism of sPMMA in toluene. The phase morphology of segmented polymer networks and the corresponding polymer blends is examined in detail by 13C NMR relaxometry in the solid state in Chapter...

  19. Poly(1,3-dithienylisothianaphtene) derivates. Synthesis, characterisation and possible applications of a new class of low bandgap materials

    VANGENEUGDEN, Dirk

  20. Studie van de relatie tussen de moleculaire structuur en de elektrische mobiliteit van poly(aryleen vinyleer)derivaten

    BREBAN, Lien

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