Zakład Fizyki Makromolekularnej
Strona główna
Zespół
Badania
Aparatura
Seminaria
Publikacje
Nasze
konferencje
Aktywność
konferencyjna
Projekty
Programy
Najbliższe
wydarzenia
Linki
Kontakt

wizyta

od 2020-09-20

Dr Maria Dobies  | 1996-10 - obecnie

Adiunkt

   WF UAM pokój: 133      +48 61-829-5247       dobies@amu.edu.pl

  0000-0003-3683-2100     6507299629  

Zainteresowania naukowe:
Zastosowanie metod NMR i reologii do badania struktury i dynamiki hydrokoloidów (analiza procesów żelowania wodnych roztworów niskometylowanych pektyn).

Publikacje                Magistrowie      Licencjusze      Seminaria


15.

Dobies M., Makrocka-Rydzyk M., Jenczyk J., Jarek M., Spontak R.J., Jurga S.

Molecular dynamics study of polystyrene-b-poly(ethylene oxide) asymmetric diblock copolymer systems Two polystyrene-b-poly(ethylene oxide) (PS-b-PEO) diblock copolymers differing in molecular mass (49 and 78 kDa), but possessing the same PEO cylindrical morphology, are examined to elucidate their molecular dynamics. Of particular interest here is the molecular motion of the PEO blocks involved in the rigid amorphous fraction (RAF). Analysis of complementary thermal calorimetry and X-ray scattering data confirm the presence of a microphase-separated morphology, as well as semi-crystalline structure, in each copolymer. Molecular motion within the copolymer systems is monitored by dielectric and nuclear magnetic resonance spectroscopies. Results reported herein reveal the existence of two local, Arrhenius-type processes attributed to non-cooperative local motion of PEO segments involved in fully amorphous and rigid amorphous PEO microphases. In both systems, two structural relaxations governed by glass transition phenomena are identified and assigned to cooperative segmental motion in the fully amorphous phase (the αc process) and the RAF (the αc process). We measure the temperature dependence of the dynamics associated with all the processes mentioned above and propose that these local processes are associated with corresponding cooperative segmental motion in both copolymer systems. In marked contrast to the thermal activation of the αc process as discerned in both copolymers, the αc process appears to be a sensitive probe of the copolymer nanostructure. That is, the copolymer with shorter PEO blocks exhibits more highly restricted cooperative dynamics of PEO segments in the RAF, which can be explained in terms of the greater constraint imposed by the glassy PS matrix on the PEO blocks comprising smaller cylindrical microdomains.

Langmuir, 33(36), 8856-8868 (2017)

DOI: 10.1021/acs.langmuir.7b02017   (Pobrane:  2020-10-23)


14.

Dobies M., Iżykowska J., Wilkowska M., Woźniak-Braszak A., Szutkowski K., Skrzypczak A., Jurga S., Kozak M.

Dispersion of water proton spin-lattice relaxation rates in aqueous solutions of multiwall carbon nanotubes (MWCNTs) stabilized via alkyloxymethylimidazolium surfactants Carbon nanotubes and a number of other carbon nanomaterials have a tendency to aggregate, which often resulted in difficulties of dispersion of these nanomaterials in aqueous solutions. The ability of dicationic (gemini) surfactants to disperse multiwall carbon nanotubes in water and the dynamic processes taking place at the water-MWCTs interface are studied. Stable dispersions of multi-wall carbon nanotubes with selected gemini surfactants (1,1’-(1,6-hexanediyl)bis(3-alkyloxymethylimidazolium) dichlorides) were prepared and characterized by nuclear magnetic relaxation dispersion (NMRD), NMR diffusometry, scanning and transmission electron microscopy, and Fourier transform infrared spectroscopy. The addition of multiwall carbon nanotubes to aqueous solutions of studied gemini surfactants leads to significant paramagnetic enhancement of the spin-lattice relaxation processes, which gets more pronounced with increasing concentration of well-dispersed MWNTs in water. The dominant role of outer sphere (OS) relaxation mechanism in total observed R1, governed by two-dimensional diffusion of water on the carbon nanotube surface in the vicinity of paramagnetic centers incorporated in the MWCNTs side-walls (mainly of iron origin), was assumed to explain NMRD data. The NMR diffusion experiments confirm the existence of restricted water diffusion in the studied supernatants. The NMR diffusion results are consistent with the FTIR and NMR proton spin-lattice relaxation dispersion in which the more effective R1 dispersion noticed for the sample with IMIC6C12 was ascribed to the better accessibility of water molecules to the surface of the MWCNTs.

The Journal of Physical Chemistry, 121(21), 11839-11850 (2017)

DOI: 10.1021/acs.jpcc.7b01801


13.

Skupin M., Iżykowska J., Andrzejewska W., Dobies M., Jurga S., Kozak M.

Abstrakt lub materiały konferencyjne, albo abstrakt publikacji
z dodatkowymi numerami DOI

Interactions of carbon nanotubes stabilized by selected gemini surfactants with model biomembranes Thanks to the extraordinary mechanical strength and high electrical conductivity multiwalled carbon nanotubes are currently used in electronics, medicine (as biomedical sensors, transporters or drugs) as well as in the production of lightweight and durable construction. The aim of this study was to determine the possibility to use different cationic gemini surfactants with different spacer lengths or alkyl chain lengths in more efficient systems for dispersing nanostructures in aqueous solutions. The most important advantages of these systems are their non-immunogenic, biocompatible properties and generally low toxicity . Therefore nanotubes, surrounded by surfactants, have the potential to interact with biological membranes. For this purpose we studied the influence of dispersed CN solution on the phase behavior of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) - a phospholipid most often present in membranes of nerve cells. The microstructure of the stable suspension of carbon nanotubes was investigated using high-resolution Transmission Electron Microscopy and Atomic Force Microscopy. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to analyze the influence of surfactants studied, used for CN dispersion, on the phase behavior of DMPC bilayers. A series of measurements of toxicity of these systems were performed in HeLa and fibroblast cell cultures. This work was supported by the Ministry of Science and Higher Education, within the project “Najlepsi z najlepszych!” dec.

Biophysical Journal, 112(3) S1, 77A (2017)

DOI: 10.1016/j.bpj.2016.11.460   (Pobrane:  2020-11-05)


12.

Iżykowska J., Skupin M., Andrzejewska W., Dobies M., Jurga S., Kozak M.

Abstrakt lub materiały konferencyjne, albo abstrakt publikacji
z dodatkowymi numerami DOI

Carbon nanostructures of different spatial geometry: their dispersion and influence on model biological systems The discovery of carbon nanostructures (CN) in the last century has revolutionized science, opening new research opportunities in biophysics, material sciences, biomedicine and pharmacology [1]. Unfortunately, carbon nanomaterials show a strong tendency towards aggregation and poor stability in solutions. Such properties, especially the suspension stability, are critical for bio-applications of carbon nanostructures [2]. Surface functionalization of nanocarbons improves the dispersing properties in water solutions but it may also influence their physicochemical properties [3]. For preparation of biocompatible CN samples we used novel dicationic surfactant (gemini) with imidazole head groups. Nanocarbon suspensions were investigated in the context of their anticancer activity, as well as their application as multimodal contrast/drug delivery agents. Different spatial geometries of CN may be of key importance for designing of the efficient anti-cancer system. Such systems were subjected to the cytotoxicity tests on HeLa cell cultures. The structural properties of selected, the most effective systems based on CN suspensions were characterized by the use of SEM, AFM and NMR methods. This study was supported by the Ministry of Science and Higher Education (Poland), within the project “Najlepsi z najlepszych!”

Biophysical Journal, 112(3) S1, 156A (2017)

DOI: 10.1016/j.bpj.2016.11.857   (Pobrane:  2020-11-05)


11.

Zaręba J., Iżykowska J., Skupin M., Moliński A., Dobies M., Jurga S., Kozak M.

Abstrakt lub materiały konferencyjne, albo abstrakt publikacji
z dodatkowymi numerami DOI

The influence of surfactant structure and geometry on nanotoxicity and dispersion of carbon nanotubes Graphene, nanotubes and fullerenes, also known as carbon nanomaterials (CN), because of the their unique properties have potential applications not only in preparation of new composite materials or in electronics, but they can be also components of drug delivery systems. However, the applications of CN in life sciences or biomedicine require stable dispersions of these materials in water. The hydrophobic nature of CN causes serious problems with their separation in water solutions. Our study is aimed to find a way of dispersing such CN systems in water, by the use of non-covalent surface modification via different surfactants. In this work we focused on the use of trimeric, dimeric and monomeric surfactants fornon-covalent surface modification of selected carbon nanotubes. The toxicity of these systems (aqueous solutions of CN with surfactants and surfactants solutions) towards selected cell cultures (e. g. HeLa cells) was also tested. The surfactants studied can interact with carbon nanotubes in a number of different modes: hydrophobic interactions (surfactant chains with CN side walls) or π-π interactions (aromatic rings of surfactants with CN surface). Infrared spectroscopy and atomic force microscopy were used for characterization of the systems studied. Finally, we focused on mechanical properties of cells exposed to surfactants and CN. This study was supported by the Ministry of Science and Higher Education (Poland), within the project “

Biophysical Journal, 112(3) S1, 156A (2017)

DOI: 10.1016/j.bpj.2016.11.858   (Pobrane:  2020-11-05)


10.

Woźniak-Braszak A., Jurga K., Nowaczyk G., Dobies M., Szostak M., Jurga J., Jurga S.

Characterization of poly(ethylene 2,6-naphthalate)/polycarbonate blends by DSC, NMR off-resonance and DMTA methods The poly(ethylene 2,6-naphthalate) (PEN)/polycarbonate (PC) blends with the weight ratio of homopolymers 50/50 wt./wt. were prepared by injection molding using the Engel machine ES. One mixture was synthesized without the compatibilizer and the second with the compatibilizer SMAC (Samarium acetylacetonate hydrate). The influence of the cornpatibilizer on the physical and mechanical properties of the PEN/PC blends was investigated. The thermal properties of the new synthesized blends were studied by the differential scanning calorimetry (DSC). The molecular dynamics of the polymer blends was studied by the off-resonance NMR. The correlation times of the internal motions and the spectral density function amplitudes were estimated on the basis of the dispersion of the spin lattice relaxation time T1ρ(off) in the rotating frame off-resonance. The rheological properties of the studied blends were investigated by dynamic mechanical thermal analysis (DMTA). The temperature dependencies of the storage modulus G', of the loss modulus G" and of the loss tangent (tan δ) were analyzed in order to evaluate the relaxation processes in the studied systems. The analysis of the DMTA data revealed the existence of two primary (α(1) and α(2)) and two secondary (β and γ) relaxation processes in the blend of PEN/PC 50/50 wt./wt. and one primary (α) and two secondary (β and γ) relaxation processes in the blend of PEN/PC 50/50 wt./wt with the compatibilizer. The motional parameters for the above - mentioned relaxation processes were calculated using the Havriliak Negami formalism. The comparative analysis of the DSC, NMR off-resonance and DMTA results led to the clarification of the molecular motion in the PEN/PC 50/50 wt./wt. blends.
(C) 2015 Elsevier Ltd. All rights reserved.

European Polymer Journal, 64, 62-69 (2015)

DOI: 10.1016/j.eurpolymj.2014.12.039   (Pobrane:  2020-10-23)


9.

Bilski P., Dobies M., Kozak A., Makrocka-Rydzyk M.

Autorstwo lub wspólautorstwo książki, podręcznika akademickiego, monografii, zeszytów ćwiczeń i innych materiałów dydaktycznych, a także redakcja edytorska, słowo wstępne,
w wydawnictwach naukowych ISSN lub ISBN,
oraz w wydawnictwach popularno - naukowych.

Materiały do ćwiczeń ze wstępu do pracowni fizycznej: Normy ISO i matematyka w laboratorium Podręcznik dla studentów nauk przyrodniczych (zwłaszcza fizyki) w przystępny sposób przedstawia sposoby prezentacji danych pomiarowych, opracowania wyników doświadczeń laboratoryjnych i oceniania niepewności pomiarowych zgodnie z normami ISO. Wiadomości teoretyczne i praktyczne zostały zebrane w dziewięciu rozdziałach. W pierwszym opisano współczesne podejście do eksperymentu fizycznego. W rozdziale drugim przeanalizowano ocenę niepewności pomiarowych dla najczęściej używanych przyrządów pomiarowych. Rozdziały trzeci, czwarty i piąty zawierają wiedzę ze statystyki i analizy matematycznej niezbędną do oceny niepewności standardowych typu A oraz B dla pomiarów bezpośrednich i złożonych (pośrednich), a także dla parametrów uzyskanych z analizy regresji liniowej. Rozdziały szósty, siódmy i ósmy dają studentom narzędzia matematyczne do porównania wyników pomiarów (także metodą parametrycznych testów istotności), planowania dokładniejszego eksperymentu oraz dyskusji wyników i wyciągania wniosków z przeprowadzonego eksperymentu. We wszystkich wymienionych rozdziałach znajdują się rysunki obrazujące podany materiał teoretyczny i przykłady tak skonstruowane, aby pokazać, że do ich opracowania wystarcza tylko użycie prostego programu komputerowego (np. Excel), podobnie jak w laboratoriach podstaw fizyki. Ostatni rozdział zawiera, w formie protokołów, przykładowe opracowania czterech doświadczeń fizycznych (dwóch z mechaniki i dwóch z elektryczności), w których pokazano, iż rzetelne podejście do najprostszych badań eksperymentalnych pozwala wyciągnąć z nich bardzo dużo ważnych wniosków. W aneksach podano streszczenia przedstawionej wiedzy, przydatne zwłaszcza na poszczególnych etapach opracowywania wyników pomiarów. Dodano też pięć tablic statystycznych umożliwiających dokładniejsze opracowanie pomiarów niż to zalecają normy ISO.

Wydawnictwo Naukowe Uniwersytetu im. Adama Mickiewicza, , (2014)

WWW: http://www.press.amu.edu.pl/
ISBN: 978-83-232-2745-8   (Pobrane:  2021-01-11)


8.

Jenczyk J., Dobies M., Makrocka-Rydzyk M., Wypych A., Jurga S.

The segmental and global dynamics in lamellar microphase-separated poly(styrene-b-isoprene) diblock copolymer studied by 1H NMR and dielectric spectroscopy The nuclear magnetic resonance (NMR) and dielectric spectroscopy (DS) methods were used to investigate the segmental and global dynamics in lamellar microphase separated poly(styrene-b-isoprene) (SI) diblock copolymer. For the first time, the susceptibility representation of the NMR relaxation data is applied to the analysis of the molecular dynamics in complex polymer systems like the diblock copolymer. This approach in combination with the frequency-temperature superposition (FTS) allows one to compare directly the NMR and DS data in an extended frequency range providing a unique comprehensive picture of various relaxation processes present in the system studied. The findings of these investigations include structural relaxations of the polyisoprene (PI) and the polystyrene (PS) blocks, a normal mode relaxation of the PI block, and an extra low frequency interfacial relaxation. Special attention has been devoted to influence of the copolymer morphology on the segmental and global dynamics in PI.
(C) 2013 Published by Elsevier Ltd.

European Polymer Journal, 49(12), 3986-3997 (2013)

DOI: 10.1016/j.eurpolymj.2013.09.003   (Pobrane:  2020-10-23)


7.

Makrocka-Rydzyk M., Wypych A., Dobies M., Jancelewicz M., Jurga S., Cho HY., Gao HF., Matyjaszewski K.

Molecular dynamics in PBA/PEO miktoarm star copolymers Molecular dynamics of miktoarm star copolymers consisting of poly(n-butyl acrylate) PBA and polyethylene oxide (PEO) arms was studied by means of Broadband Dielectric Spectroscopy (BDS) and Nuclear Magnetic Resonance (NMR) methods. The spectroscopic studies were performed for three types of copolymers differing in the composition, namely materials containing 76%, 46% and 16% molar fraction of PBA arms. The local processes, described by the Arrhenius law (e.g. the anisotropic rotation of methyl groups and the anisotropic local motions in the PEO chain), were observed for the studied systems below the glass transition temperature. It was found that the investigated PBA/PEO miktoarm star copolymers are characterized by single glass transition, which may result from similar values of glass transition temperatures of the PBA and PEO polymers. The segmental dynamics in the studied systems was quantitatively described by using the Vogel-Fulcher-Tammann (VFT) relation applied to combined NMR and BDS data. Moreover, above the glass transition temperature the interfacial polarization and conductivity phenomena were detected with the BDS method for all systems under study.
(C) 2013 Elsevier Ltd. All rights reserved.

Polymer, 54(13), 3341-3349 (2013)

DOI: 10.1016/j.polymer.2013.04.004


6.

Bilski P., Dobies M., Kozak A., Makrocka-Rydzyk M.

Autorstwo lub wspólautorstwo książki, podręcznika akademickiego, monografii, zeszytów ćwiczeń i innych materiałów dydaktycznych, a także redakcja edytorska, słowo wstępne,
w wydawnictwach naukowych ISSN lub ISBN,
oraz w wydawnictwach popularno - naukowych.

Analiza danych i planowanie eksperymentu fizycznego zgodnie z normami ISO W artykule przedstawiono istotę pomiaru fizycznego i niezbędne słownictwo związane z przeprowadzaniem eksperymentu fizycznego. W skrócie podano według wskazań ISO procedurę określania standardowych niepewności pomiarowych pomiarów bezpośrednich i złożonych. Porównywanie wyników pomiarów przedstawiono jako uzgadnianie ich przedziałów utworzonych na podstawie niepewności standardowej rozszerzonej. Pokazane sposoby planowania pomiarów pozwalają określić, czy eksperyment można uznać za zakończony. Procedury takie umożliwiają zaplanowanie dokładniejszych pomiarów oraz są bardzo pomocne przy formułowaniu wniosków podsumowujących przeprowadzone doświadczenie.

Postępy Fizyki, 64(2), 70-75 (2013)

WWW: http://www.ptf.net.pl/pl/aktualnosci/informacje-biezace/archiwum-postepow-fizyki/
ISSN: 0032-5430   (Pobrane:  2021-01-11)


5.

Dobies M., Kozak M., Jurga S., Grubb A.

The dispersion of water proton spin-lattice relaxation rates in aqueous human protein HC (α1 - microglobulin) solutions The H-1 NMR Fast Field Cycling relaxometry was applied to study the molecular dynamics of the human protein HC (alpha(1)-microglobulin), its hydration and aggregation in solution state. The H-1 NMRD data have revealed the complex nature of the water/protein HC system resulting from the co-existence of monomer and dimer forms of the protein in solution as well as the presence of oligosaccharides linked to the polypeptide chain. A comparison of the average correlation time values obtained from the model-free fits with the values predicted on the basis of hydrodynamic tau(r) theory, suggests that the dynamics in solution state is governed mainly by the dimer form of the protein HC (the dominant contribution to the water proton-spin lattice relaxation comes from exchanging protons from the surface of the dimer). The existence of small number of oligomeric forms of the protein HC in solutions is postulated because of the two-step shape of water proton spin-lattice relaxation rate dispersion profiles.

Protein and Peptide Letters , 16(12), 1496-1503 (2009)

DOI: 10.2174/092986609789839241


4.

Dobies M., Kempka M., Kuśmia S., Jurga S.

Acid induced gelation of low methoxyl pectins studied by 1H NMR and rheological methods The various 1H NMR techniques (1H NMRD, water proton spin-spin relaxation time and diffusion measurements) in combination with rheological measurements were applied to the analysis of the acid induced gelation of 3% w/w aqueous LM pectin solutions at 279 K. A decrease of the pH value of solutions from 5 to 2.6 leads to a slowdown in the dynamics of the water molecules and to a substantial modification in the structure of the system studied. The most significant changes in the 1H NMRD and T2 measurements were observed when the pH was varied from 5 to 3, which reflected an increase in the stiffness of the pectin chains caused by non-ionic associations and by an increase of water molecules that were trapped between the pectin chains in the gelled ste. The results obtained by the rheological method are consistent with those of 1H NMR, indicating a solution-like mechanical response for the sample at pH 5 and a gel-like response at pH 3. Results of 1H NMR measurements have also shown an important role for aggregation processes of the LM pectin molecules in the acid-induced gel network formation.

Applied Magnetic Resonance, 34(1-2), 71-81 (2008)

DOI: 10.1007/s00723-008-0107-7   (Pobrane:  2020-10-21)


3.

Limanowska-Shaw H., Dobies M., Wierzbicki T.

Polski Przegląd Nauk o Zdrowiu, 5, 58-62 (2005)

WWW: http://www.przeglad.amp.edu.pl/


2.

Dobies M., Kuśmia S., Jurga S.

1H NMR and rheological studies of the calcium induced gelation process in aqueous low methoxyl pectin solutions The H-1 NMR relaxometry in combination with water proton spin-spin relaxation time measurements and rheometry have been applied to study the ionic gelation of 1% w/w aqueous low methoxyl pectin solution induced by divalent Ca2+ cations from a calcium chloride solution. The model-free approach to the analysis of H-1 NMR relaxometry data has been used to separate the information on the static (β) and dynamic (<τ(c)>) behaviour of the systems tested. The H-1 NMR results confirm that the average mobility of both water and the pectin molecules is largely dependent on the concentration of the cross-linking agent. The character of this dependency (β, <τ(c)> and T-2 vs. CaCl2 concentration) is consistent with the two-stage gelation process of low methoxyl pectin, in which the formation of strongly linked dimer associations (in the range of 0-2.5 mM CaCl2) is followed by the appearance of weak inter-dimer aggregations (for CaCl2 >= 3.5 mM). The presence of the weak gel structure for the sample with 3.5 mM CaCl2 has been confirmed by rheological measurements. Apart from that, the T1 and T2 relaxation times have been found to be highly sensitive to the syneresis phenomenon, which can be useful to monitor the low methoxyl pectin gel network stability.

Acta Physica Polonica A, 108(1), 33 (2005)

DOI: 10.12693/APhysPolA.108.33
WWW: http://przyrbwn.icm.edu.pl/APP/PDF/108/a108z104.pdf   (Pobrane:  2021-01-10)


1.

Dobies M., Kozak M., Jurga S.

Studies of gelation process investigated by fast field cycling relaxometry and dynamical rheology: the case of aqueous low methoxyl pectin solution The Fast Field Cycling Relaxometry and the dynamical rheology were applied to study the gelation process in aqueous low methoxyl pectin solution in the presence of divalent cations from the calcium chloride. The model-free approach to the analysis of H-1 NMRD data was used to separate the information on the static and dynamic behaviour of the system provided by the dispersion profiles of the systems tested. Mechanical spectroscopy was applied as a complementary method to probe the network formation. The structural changes were most pronounced for the concentration of calcium chloride between 10 and 15 mM (the static parameter beta was found to vary from 0.936 x 10(7) to 1.27 x 10(7) 1/s(2)) revealing the sol-gel transition on visual inspection. The presence of the gel network was confirmed by the rheological measurements. All mechanical spectra exhibited the gel like character, and the solid like response was more evident at higher concentrations of calcium cations. The mean correlation time increased with increasing salt concentration, but remained unchanged for the concentrations above 15 mM. The dynamical changes were most significant at the phase transition from the sol to the gel state.
(C) 2003 Elsevier Inc. All rights reserved.

Solid State Nuclear Magnetic Resonance, 25(1-3), 188-193 (2004)

DOI: 10.1016/j.ssnmr.2003.03.019   (Pobrane:  2020-10-21)


 © Opisy i zdjęcia: Zakład Fizyki Makromolekularnej  | Ta stona używa ciasteczek
     Zaktualizowano: podstrony  2021-06-21  / bazę danych:   2021-08-30  by Webmaster: Zbigniew Fojud