In the theoretical part of this work it is shown that the Lamm´s Differential Equation for polymer solutions can be extended to swollen polymer networks, if the phenomenological equations and the equation for the chemical potential of the polymer component in the network are taken into account. All differences for a transition from a polymer solution to a swollen polymer network can be assigned a "Elastically active coefficient E", which describes a deformation velocity with the same unit as the diffusion coefficient. In the practical part of this thesis some new improvements/developments regarding the Schlieren optical system are introduced and discussed. In the part "Results and Discussion" the results of the centrifugal measurements of gelatine gels are presented and discussed. The following evaluation of the centrifugal runs of polyacrylat gels (chemical networks) and the comparison with the results of the gelatine gels (physical networks) shows clearly that the new theory is suitable to describe the move ment of the polymer component in the network in a centrifugal field quantitatively as well as qualitatively.

Host and guest compounds self-assemble to supramolecular complexes. Noncovalent bonding donor-acceptor-interactions of supramolecular complexes like that of J. F. Stoddart et al. can be weakened by redox reactions, but the complexes desintegrate. Here, it is described the reversed way. The initial reaction mixture contains a host and a potential guest compound not interacting with each other. The potential guest compound will be transferred in a real guest compound by electrochemical reduction and the supramolecular complexation is induced. Tetracationic, electronwithdrawing cyclophanes with two redoxactive units of 4,4-bipyridindiium respectively 2,7-diazapyrendiium act as host compounds, electronwithdrawing quinones as potential guest compounds. The host and guest compounds and their interaction in complex are characterized and studied by cyclic voltammetry and spectroelectrochemistry. It can be demonstrated that the reduction potentials are shifted, that the cyclophane and the guest compound form an inclusion complex and that the inclusion complexes are low soluble, exclusion complexes well soluble.

In inductively coupled plasma spectrometry, signal suppression by acids has been recognized for a long time. It is always explained as the physical effects on the sampling processes, plasma conditions, and aerosol properties. In some cases, signal suppression apparently relates to the chemical properties of element. However, there was no publication discussed this phenomenon. In this work, it has been proven that mercury signal suppression depends on the plasma properties and nitric acid concentration. It relates to the atomization yield of mercury compounds, which is governed by the red-ox equilibrium in the central channel of plasma. Mercury complex formation equilibrium has been proven to exert in the heated droplets in plasma. The equilibrium state is governed by the complex formation with ammonium nitrate, the complex dissociation by nitric acid, and the heat obtained from plasma. Mercury halogen complex is not sensitive to the changes in acidity. Therefore, it is able to keep mercury free from nitric acid interferences and unify mercury atomization in the central channel of plasma. Similar to mercury, the uncertain signal and memory effect of platinum group elements and gold mainly arises from the chemical interference on the atomization efficiency. It not only depends on nitric acid concentration, but also on the standard reduction potential (Eo) of precious metal species in solution. Chemical interference on the spectrometric signals is governed by the robustness of the plasma, the capabilities to ingest aerosol and to protect foreign disturbance. The robustness of plasma is not equal to the excitation conditions. It has been observed that nitric acid has no significant interferences on mercury signal intensity of MIP-OES. When wet aerosol enters into the resonant cavity, it is completely desolvated in the powerful electromagnetic field. Liquid phase instantly disappears from the plasma observation zone. No doubt, the chemical equilibrium does not exist. In conclusion, chemical reactions exist in the plasma and interference the spectrometric signal. The best way to overcome the chemical matrix interferences in the plasma source spectrometry is to realize the controllable atomization.

Nanocapsules are generally considered as spherical, hollow structures. Important potential applications are pharmaceutically related such as drug targeting and controlled release. Typically, the capsules consist of a polymeric wall, filled with an oil which can dissolve lipophilic agents. To enable a stable aqueous dispersion, the capsule surface is covered by an amphiphilic surfactant. Nanocapsule-dispersions were investigated by means of solid-state nmr. Cross polarization experiments revealed the morphology of the polymeric wall. Further, the spin-lattice relaxation times for the proton magnetization in the rotating frame were studied under direct excitation as well as under cross polarization conditions. Based on the results, a special mechanism of cross polarization is proposed, initiated by a temporary adsorption of mobile oil- and surfactant-molecules to the more rigid capsule surface. - Nanokapseln sind sphärische, hohle Objekte, die in der Medizin als gewebespzifische Wirkstoff-Träger-Systeme eingesetzt werden sollen. Vereinfacht bestehen die Kapseln aus einem Öltropfen, der von einem Polymergerüst umgeben ist. In die innere Ölphase können lipophile Wirkstoffe eingeschlossen werden. Die Nanokapselwand ist mit einer Tensidschicht umgeben, die stabilisierend wirkt und ermöglicht, dass die Kapseln in einer wässerigen Phase dispergiert werden können. Als analytische Methode wurde die Festkörper-NMR-Spektroskopie gewählt. Die Morphologie der Polymerwand wurde mit Kreuzpolarisationsexperimenten aufgeklärt. Zusätzlich wurden die Relaxationszeiten im rotierenden Koordinatensystem der Protonen unter Direktanregungs- und Kreuzpolarisationsbedingungen untersucht. Die Ergebnisse dieser Untersuchungen konnten mit einer temporären Adsorption der Öl- und Tensidmoleküle an der Nanokapseloberfläche interpretiert werden.

In most cases chemometric methods (PCA, PCR, PLS) are used for data modelling when NIR-spectrometry is applied for analytical purposes. This work is about the application of the wavelet-transform as a tool in chemometrics for analysing NIR-spectra. Beside aspects of data pretreatment, like smoothing of NIR-spectra, and data compression the focus was set on NIR-analysis using wavelet-transformed NIR-spectra. A new method for building multivariate calibration models based on wavelet-coefficients selected by a genetic algorithm is introduced. In addition the results obtained by calibrating wavelet-coefficients using PCR and PLS are descriped. Furthermore the identification of post consumer plastic waste by wavelet-transformed NIR-spectra and an artificial neural network is demonstrated. Two new special types of wavelets which allow analysing finitely extended signals (like spectra) without introducing artifacts near the boundaries were applied

The visual pigment of vertebrates (rhodopsin), a member of the large class of G-protein-coupled receptors, and the photosynthetic pigment bacteriorhodopsin of halobacterium salinarum, an active pump, contain retinal as prosthetic group. The replacement of the native retinal by analogue chromophores helps to understand the molecular function of the light sensitive ligands. In order to study the intermolecular interaction between chromophore and protein three retinal derivatives were synthesized and incoporated (9-desmethylretinal, 9-ethylretinal and 9-isopropylretinal) which together with the native chromophore constitute a homologous series with systematically changed size of the substituent at position 9. In addition three analogue retinals with modification at position 10 and/or 13 (10-methylretinal, 13-demethylretinal and 10-methyl-13-demethylretinal) were also synthesized and studied particulary to understand the intramolecular interaction of the chromophore of rhodopsin.

This paper deals with the possibilities of using spark emission spectrometry to determine nitrogen contents in low-alloy steels. Several spectrometers, whose installation sites include two automatic laboratories at Thyssen Krupp Stahl AG in Duisburg, were used to carry out the practical work. Once the appropriate analysis line had been selected and the excitation conditions had been optimised, calibrations were carried out and spectral intereferences and analytic performance data were determined. Finally, the analysis results obtained from the production samples during manual and automatic operation were compared using the carrier gas hot extraction method, which is the standard reference method. Single spark spectrometry forms another focus. This makes it possible to register and evaluate the intensities of every single spark transfer. It also enables information to be obtained concerning the qualitative and quantitative composition of inclusions in steel, e.g. nitrides. The decomposition behaviour of inclus ons over time was analysed by spark discharges with the help of both SEM-EDX and single spark spectrometry.

This work deals with the preparation and characterisation of poly(n-butyl-2-cyanacrylate) nanocapsules. The mean applications of these particles are their use as drug-carriers, in order to increase the efficiency and to reduce the side effects of pharmaceuticals. By coupling size exclusion chromatography with multi angle laser light scattering a procedure for size determination of nanocapsules is developed. In this connection the analysis of the light scattering data is discussed in detail. Concerning the optimization of the capsule preparation, the influences of different parameters (components concentration, type of stirrer and sample preparation) on the size and size distribution of the nanocapsules are determined. Regarding the characterisation of the polymer cover, the wall thickness as well as the molecular weight distribution of the polymer are analysed. Further, the capsule wall is simulated by a planar polymer film. Rheologic and H-NMR investigations on this film allow to observe the kinetics of wall formation. The rheologic measurements give additional information about the viscoelastic properties and the cross linkage of the polymer.

In the thesis the gelation of the system gelatin / water was investigated by use of rheological and optical methods. The rheological properties were taken to describe the gelation in terms of the percolation theory. In order to determine the gel point and the critical exponents a potential law found by Stauffer and de Gennes that describes the development of the storage and loss modulus was used to express normalized percolation approches. This normalized percolation ansatzes delivers a single very exact gelation time and the information which range should be taken for the evaluation. Combining the storage and the loss modulus symmetrically around the gel point novel so called combined percolation functions were formulated. From these combined functions the critical exponents could likewise be determined. The simultaneous measurements of the rheological and optical properties clearly show that close to the gel point the loss and the storage modulus as a function of time as well as a function of the optical rotation could be described in terms of the percolation theory. Furthermore an aggregation model was formulated that describes the development of the storage modulus close and far away from the gel point, respectively.

Halogeno(pentafluorophenyl)silanes (C6F5)nSiX4-n(X=F, Cl, Br;n=2,3) and halogno(methyl)pentafluorophenylsilanes C6F5SiMenX3-n(X=F, Cl, Br; n=1,2) were prepared in good yields from the corresponding phenylsilanes (C6F5)n SiPh4-n and C6F5SiMenPh3-n by reactions with the electrophiles aHf, HCl - AlCl3, Br2 - AlBr3 or AlX3 (X=Cl, Br) - halogenated hydrocarbons. Additionally, reactions of (C6F5)2SiMe2 with selected electrophiles are studied and new synthetic routes to C6F5SiF3 are described. The relative leaving ability of organyl groups bonded to silicon and the role of the electrophilic reagent are discussed