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Stimuli Responsive Multicomponent Polymer Systems
Šťastná, Julie ; Hanyková, Lenka (advisor) ; Dušková - Smrčková, Miroslava (referee) ; Labuta, Jan (referee)
Title: Stimuli Responsive Multicomponent Polymer Systems Author: Julie Šťastná Department: Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics Supervisor: doc. RNDr. Lenka Hanyková, Dr., Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics Abstract: Combination of 1 H NMR spectroscopy, differential scanning calorime- try (DSC), dynamic mechanical measurement, and optical microscopy was used to investigate temperature-induced phase transition of three types of systems: i) in D2O solutions of poly(N-isopropylmethacrylamide-co-acrylamide) (P(NIPMAm/- AAm)) random copolymers and in interpenetrating networks ii) poly(N-isopropyl- methacrylamide/poly(N-isopropylacrylamide) (PNIPMAm/PNIPAm), and iii) po- ly(vinylcaprolactam)/poly(N-isopropylacrylamide) (PVCL/PNIPAm). In all sys- tems influence of composition of the system on the phase transition was studied. For i) both the NMR and DSC data showed dependence on the acrylamide (AAm) content in the copolymer. NMR data was used to construct van't Hoff plots and changes of the enthalpy ∆H and entropy ∆S were studied. As it follows from comparison of ∆H values for NMR and DSC the size of the domains undergoing the transition as a whole decreases with increasing AAm...
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Study of molecular dynamic behaviour in mixtures water/ethanol
Radecki, Marek ; Hanyková, Lenka (advisor) ; Labuta, Jan (referee)
In the diploma work we studied mixtures of water, ethanol and poly(vinyl methyl ether) (PVME) by the methods of Nuclear Magnetic Resonance (NMR) and Differential Scanning Calorimetry (DSC). NMR studies of water/ethanol binary mixtures between 10 - 90 vol.% of ethanol for wide temperature range comprised chemical shifts, relaxation times, translation diusion coecients, Nuclear Overhauser Eect of ethanol spectra and calculation of hydrodynamical radii. Most of the results show extremal values around 50 vol.% of ethanol. DSC provides measurements of pure PVME, water and ethanol, then binary water/ethanol mixtures and PVME/water/ethanol mixtures in the whole ethanol concentration region and low PVME concentrations. The high concentratios of the PVME/water mixtures were prepared and measured. We obtain detailed description of PVME/water/ethanol mixtures - glass transition temperature, crystallization, melting and phase separation temperature.
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