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Study of temperature-induced phase separation in copolymer solutions
Šťastná, Julie ; Hanyková, Lenka (advisor)
Tit lr: Study of tempera! urc-indneed phase M'paNil ion in cnpol VIIKT noli it ions. Author; .Intie IJriilliiva I Jepar! incut; Department of MiUTOinnleeulai1 |']IVM< .- Supervisor: KM )r.l,enka llauvkova. Dr. Hnpervisoi ' - e-mail address- hanykova" l-imf I loja.mil.cnni.r/ Absl ract: I'lif tcinpci.ii ui I'-indnrcd pi MM' 11 HUM! ion oi pi)ly(;KT\/ A -iiMipropvlnirt h.u-i \- nniiilc) r;nidnru n>|]o|vnici - in [>_>(> snlui ion^ and in mixl mv^ of Dj<) 'd h.iuul ;ind DjO 'acftnn i^ it tidiI'd in linn work. I In.-, plir-immciHMi i.-> on [ lie nmicciihn1 level ;ni;ilof.',nu^ w i t ii ;i phiisc transit ion (coll,-i|ivcl in hydi o;.',cls. Nuclear ina^iiciic rcsnn.imc [ N M I ' ) ->pret n>^e',ip\ v.'a- u-cd tm' the ~lnd>". liesull.h sho\ved thill w i t h nici'i'.i^i nj1, c< ml ent of acrylaiuide in t lie ci >poi\niei1 i he i ra nation r<iinpc- laMii'e i> shifted lo hijdici1 \".ihic-~. t h e 11 aiisit ii ni is iimcc 1^1 adiial ;nid sinallei1 fi'ai I inn of copulx'Uiei is pluihf se|>ai'a!ed. The same liehavionr \\-as fniind ior hiidn-i enntenl i if ct lianol or aeetnne in 1 he Mtlvent. If This emiteiit and t h e content ut" arrylaiuidi' is very ln,",li. the pliaM.' transition in dc pci i delice on the eompo-it ion of snh-cnl appejir- The relnxat ion cxpciinient- sh(J\\-cd ( ha! alter ihe |)hase -eparntion a p;nt...
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Measurement of transverse relaxation using spin echo methods
Škoch, Antonín ; Tošner, Zdeněk (advisor) ; Hanyková, Lenka (referee)
Title: Measurement of transverse relaxation using spin echo methods Author: MUDr. Antonin Skoch, Ph.D. Department: Department of Low Temperature Physics Supervisor: RNDr. Zdenek ToSner, Ph.D. NMR laboratory, of Faculty of science, Charles University in Prague Supervisor's e-mail address: tosner(o)karlov.mff.cuni.cz Abstract: The study of TI relaxation in systems with homonuclear J-coupling is complicated by modulation in the relaxation curve. This J-modulation can be removed when CPMG sequence is used and the period of repetition of refocusing pulse Tfulfils a condition r « * ( 1 ) Ai' where Av is the frequency difference of coupled nuclei. However, the condition (I) cannot be in practice always fulfilled. The aim of this work was to investigate J-modulation and relaxation behaviour of homonuclear J-coupled system in various parameters of CPMG sequence. Simulations based on numerical solution of Liouville-von Neumann equation and Redfield theory were performed. Relaxation curves of Chh group of citrate were measured on high-resolution NMR spectrometer. It was found that the suppression of J-modulation can be achieved also for T longer than required by the condition (1) providing that the refocusing angle in CPMG for both J-coupling partners 9^180ř. The simulations yielded conditions for T when J-modulation...
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Structure and properties of nanophase separated hydrogels
Lungová, Marta ; Hanyková, Lenka (referee) ; Krakovský, Ivan (advisor)
A central goal of this work is study of structure and mechanical and thermal properties of hydrogels prepared by swelling of hydrophilic polymer networks in water. To this purpose series of epoxy networks was prepared by reaction of ,- diamino terminated poly(oxypropylene)-b-poly(oxyethylene)-b-poly(oxypropylene)- with aromatic diepoxide (Bisphenol A propoxylate diglycidyl ether). Network formation process was monitored by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Nanophase separation in the networks prepared has not been found by dynamic mechanical analysis (DMA) or differential scanning calorimetry (DSC). On the other hand, nanophase separated structure of the hydrogels has been revealed by small-angle neutron scattering (SANS). SANS data were fitted well using Teubner-Strey model based on the locally lamellar structure of water-rich and water-poor nanodomains and values of model parameters are determined. Formation of nanophase separated structure is attributed to high difference in the interaction of network components with water. Influence of water on thermal transitions in hydrogels is studied by DSC.
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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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