Zakład Fizyki Makromolekularnej
Strona główna


od 2020-09-20

Dr Jacek Jenczyk  | 1999-10 <> 2011-12


   WF UAM pokój: 133 / CNBM UAM      +48 61-829-5247

  0000-0003-1700-6719     24773128700     

Zainteresowania naukowe:
Polimery - ich dynamika molekularna oraz struktura

Publikacje                          Seminaria


Wiesner M., Roberts R.H., Lin J.F., Akinwande D., Hesjedal T., Duffy L.B., Wang S.M., Song Y.X., Jenczyk J., Jurga S., Mróz B.

The effect of substrate and surface plasmons on symmetry breaking at the substrate interface of the topological insulator Bi2Te3 A pressing challenge in engineering devices with topological insulators (TIs) is that electron transport is dominated by the bulk conductance, and so dissipationless surface states account for only a small fraction of the conductance. Enhancing the surface-to-volume ratio is a common method to enhance the relative contribution of such states. In thin films with reduced thickness, the confinement results in symmetry-breaking and is critical for the experimental observation of topologically protected surface states. We employ micro-Raman and tip-enhanced Raman spectroscopy to examine three different mechanisms of symmetry breaking in Bi2Te3 TI thin films: surface plasmon generation, charge transfer, and application of a periodic strain potential. These mechanisms are facilitated by semiconducting and insulating substrates that modify the electronic and mechanical conditions at the sample surface and alter the long-range interactions between Bi2Te3 and the substrate. We confirm the symmetry breaking in Bi2Te3 via the emergence of the Raman-forbidden A(2u)(2) mode. Our results suggest that topological surface states can exist at the Bi2Te3/substrate interface, which is in a good agreement with previous theoretical results predicting the tunability of the vertical location of helical surface states in TI/ substrate heterostructures.

Scientific Reports, 9, 6147 (2019)

DOI: 10.1038/s41598-019-42598-9   (Pobrane:  2020-12-30)


Jenczyk J., Woźniak-Budych M., Jancelewicz M., Jarek M., Jurga S.

Structural and dynamic study of block copolymer - Nanoparticles nanocomposites Nanocomposites based on block copolymer (BCP) and gold nanoparticles (NPs) filler were measured in terms of their structure and polymer chain molecular dynamics. NPs were functionalized in order to gain selective affinity to one specific type of BCP domain. BCP directed NPs assembly was monitored using atomic force microscopy. Thin nanocomposite films were fabricated via spin-coating technique, annealed and subsequently subjected to reactive ion etching in order to expose inorganic NPs location within the BCP matrix. Selective NPs incorporation was confirmed. Furthermore, interesting NPs distribution in quasi-2D crystallites was revealed. Spectroscopic methods (nuclear magnetic resonance and dielectric spectroscopy) enabled investigation of polymer chain reorientations and estimation of the impact of nano-filler on polymer dynamics. Nanocomposite crystallinity was assessed via thermal analysis and supported by spectroscopic techniques.

Polymer, 167, 130-137 (2019)

DOI: 10.1016/j.polymer.2019.01.080   (Pobrane:  2019-03-19)


Pajzderska A., Drużbicki K., Gonzalez M.A., Jenczyk J., Mielcarek J., Wąsicki J.

Diversity of methyl group dynamics in felodipine: a DFT supported NMR and QENS study Molecular and vibrational dynamics in a widely used calcium channel blocker, felodipine form I (FLD), have been thoroughly explored by combining periodic density functional theory (plane-wave DFT) with solid-state nuclear magnetic resonance (NMR), high-resolution quasielastic neutron scattering (QENS) and inelastic neutron scattering (INS) experiments. The crystallographic structure of FLD is found to be strongly stabilized by a manifold of stacking interactions, highly immobilizing the molecular frameworks and bringing on considerably anharmonic lattice dynamics, further probed by combining ab initio molecular dynamics simulations with phonon calculations. The performance of modern van der Waals corrections to density functional theory has been critically examined and compared with the results of the INS and NMR experiments. The experimental results uncover rich internal reorientational dynamics, spanning almost four orders of magnitude on the time-scale. On the basis of the combined experimental and computational protocols, the relaxation processes have been probed in a broad range of temperatures and frequencies and characterized in terms of their type, time scale and the associated activation barriers. The internal molecular mobility of FLD can be associated with the reorientational dynamics of four methyl groups, accompanied by high-amplitude librations of an alkyl ester side chain. Noticeably, internal molecular reorientations dominate above ca. 100 K, whereas motions of considerable quantum nature are clearly observed at low temperatures. In such a way, a consistent picture of the molecular dynamics in the most stable form of FLD is provided, facilitating our understanding of the relationships between the crystal environment, molecular mobility and conformational flexibility in this important pharmaceutical solid.

Crystengcomm, 20(45), 7371-7385 (2018)

DOI: 10.1039/c8ce01605d   (Pobrane:  2019-03-19)


Drużbicki K., Pajzderska A., Chudoba D., Jenczyk J., Jarek M., Mielcarek J., Wąsicki J.

Elucidating the structure of Ranitidine Fydrochloride form II: insights from solid-state spectroscopy and ab initio simulations We present a complex, computationally supported solid-state spectroscopy study, elucidating the local order in a blockbuster anti-ulcer drug, ranitidine hydrochloride form II. To this end, dispersion-corrected periodic density functional theory calculations were combined with powder X-ray diffraction, solid-state nuclear magnetic resonance, and lowfrequency vibrational spectroscopy, delivering a refined structural model. We found that a competition of nearly iso-energetic substructures, formed by enamine-type species, gives rise to the formation of several potential polymorphs. The considered models were critically examined in terms of both the stabilization energy and the spectral response. While previous studies left the crystal structure considered to be conformationally disordered at a molecular level, we found that the disorder is realized far beyond the local molecular arrangement, elucidating formation of infinite nets of hydrogen-bonded chains, linking both Z and E enamine fragments. Contrary to the previously proposed model, such an arrangement is found to be highly energetically favorable, disclosing the source of the high stability of form II. An improved atomistic model has been proposed, successfully accounting for all available spectroscopic data. In particular, we examine the presented structural arrangement to perfectly describe both optical and neutron terahertz fingerprints, representing string and robust assessment of the validity of the crystal structure with its sensitivity to the crystal packing and the intermolecular forces present therein.

Crystal Growth & Design, 18(8), 4671-4681 (2018)

DOI: 10.1021/acs.cgd.8b00639   (Pobrane:  2019-03-19)


Jenczyk J., Woźniak-Budych M., Jarek M., Jurga S.

Structural and dynamical study of PDMS and PS based block copolymers Block copolymers represent an interesting class of materials, combining properties of individual components and capable of developing nanoscopic domain morphologies. Copolymers which comprise polystyrene and poly(dimethylsiloxane) attract special attention due to their effective segregation and the highly contrasting thermal properties of individual blocks. This work covers structural studies of copolymeric domain architecture and investigates the molecular dynamics observed in bulk PDMS, diblock PS-PDMS and triblock PS-PDMS-PS. Utilization of atomic force microscopy and NMR spin diffusion provide a thorough picture of phase separated systems. Dielectric spectroscopy reveals the dynamic heterogeneity of PDMS amorphous phase. Two distinct structural relaxations, namely α and αc, were observed and attributed correspondingly to PDMS mobile amorphous fraction and PDMS rigid amorphous fraction. Unexpectedly, the segmental reorientations observed in the case of copolymers were faster that that observed for bulk PDMS.

European Polymer Journal, 98, 384-393 (2018)

DOI: 10.1016/j.eurpolymj.2017.11.045   (Pobrane:  2018-03-20)


Kiwilsza A., Milanowski B., Drużbicki K., Jenczyk J., Jarek M., Mielcarek J., Lulek J., Pajzderska A., Wąsicki J.

Molecular dynamics and the dissolution rate of nifedipine encapsulated in mesoporous silica We present the results of preliminary experiments regarding research on the contact angle measurements of various liquids on solid surfaces with different morphology. The aim was to get insight into the dependence of wetting phenomena on the nanoscale surface roughness. Flat and nanostructurized surfaces of gold and sapphire were used in the experiments. Four liquids - bromobenzene, water, mercury, and gallium - covering a broad range of surface tension values were used to check how varying roughness influences wetting in the systems with different adhesion/cohesion ratio. Structurization was anisotropic, which resulted in the very interesting behaviour of the examined liquids on the selected surfaces. Significant change of the wetting properties was observed as well as a strong dependence on the surface morphology.

Microporous and Mesoporous Materials, 250, 186-194 (2017)

DOI: 10.1016/j.micromeso.2017.05.019   (Pobrane:  2017-11-06)


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)


Kempiński M., Jenczyk J., Jurga S., Śliwińska-Bartkowiak M.

Wetting of nanostructurized sapphire and gold surfaces We present the results of preliminary experiments regarding research on the contact angle measurements of various liquids on solid surfaces with different morphology. The aim was to get insight into the dependence of wetting phenomena on the nanoscale surface roughness. Flat and nanostructurized surfaces of gold and sapphire were used in the experiments. Four liquids - bromobenzene, water, mercury, and gallium - covering a broad range of surface tension values were used to check how varying roughness influences wetting in the systems with different adhesion/cohesion ratio. Structurization was anisotropic, which resulted in the very interesting behaviour of the examined liquids on the selected surfaces. Significant change of the wetting properties was observed as well as a strong dependence on the surface morphology.

Acta Physica Polonica A, 132(1), 185-188 (2017)

DOI: 10.12693/APhysPolA.132.185   (Pobrane:  2017-11-04)


Wencka M., Apih T., Korosec R.C., Jenczyk J., Jarek M., Szutkowski K., Jurga S., Dolinsek J.

Molecular dynamics of 1-ethyl-3-methylimidazolium triflate ionic liquid studied by H-1 and F-19 nuclear magnetic resonances The molecular dynamics of an ionic liquid (IL) composed of a 1-ethyl-3-methylimidazolium cation and a triflate (trifluoromethanesulfonate) anion, abbreviated as [Emim][TfO], were studied by NMR spectroscopy. By measuring the temperature-dependent high-field H-1 and F-19 spin-lattice relaxation (SLR) rates, the frequency-dependent H-1 and F-19 SLR dispersion curves using fast-field-cycling relaxometry, and the temperature-dependent H-1 and F-19 diffusion constants, and by utilizing the fact that the primary NMR-active nucleus on the Emim cation is 1H, whereas on the TfO anion it is F-19, the cationic and anionic dynamics were studied separately. A single theoretical relaxation model successfully reproduced all the experimental data of both types of resonant nuclei by fitting all the data simultaneously with the same set of fit parameters. Upon cooling, [Emim][TfO] exhibited a supercooled liquid phase between T-SL = 256 K and the crystallization temperature T-Cr approximate to 227-222 K, as confirmed by differential scanning calorimetry (DSC) experiments. Theoretical analysis revealed that within the liquid and the supercooled liquid states of [Emim][TfO], the H-1 and F-19 relaxation rates are affected by both the rotational and translational diffusional processes with no discontinuous change at TSL. While the rotational diffusion is well described as an Arrhenius thermally activated process, the translational diffusion undergoes strong freezing dynamics that are well described by the Vogel-Fulcher model assuming a freezing temperature of T-0 = 157 K. The existence of the supercooled liquid region in the [Emim][TfO] IL should be taken into account when using this IL for a specific application.

Physical Chemistry Chemical Physics, 19(23), 15368-15376 (2017)

DOI: 10.1039/c7cp01045a


Jenczyk J., Woźniak-Budych, M., Jarek M., Grzeszkowiak M., Nowaczyk G., Jurga S.

Nanoparticle string formation on self-assembled copolymer films Nanoparticles (NP) string formations on self-assembled copolymeric substrates has been observed. These "thread of beads" like structures develop via simple colloidal droplet evaporation during meniscus rim withdrawal on polystyrene-block-poly(ethylene oxide) (PS-PEO) copolymer surfaces. It is shown that the process is triggered by the presence of the substrate impurities, which lead to NP aggregate formations serving as string initiation sites. The growth mechanism of these linear structures seems to be capillarity-driven. Moreover, there is an exceptional alignment coupling between NP strips and the block copolymer (BC) domains observed. BC directed NP assembly stems from a gold nanocrystal surface functionalization, which introduces selective affinity for one particular type of BC domain. The presented results reveal a potential fabrication method of NP wires characterized by remarkably low width and thickness comparable with the size of the individual constituent NP.

Applied Surface Science, 406, 235-244 (2017)

DOI: 10.1016/j.apsusc.2017.02.143


Bilski P., Drużbicki K., Jenczyk J., Mielcarek J., Wąsicki J.

Molecular and vibrational dynamics in the cholesterol-lowering agent lovastatin: solid-state NMR, inelastic neutron scattering, and periodic DFT study Molecular and vibrational dynamics of a widely used cholesterol-lowering agent, lovastatin, have been studied by combining nuclear magnetic resonance relaxation experiments (H-1 NMR) with inelastic neutron scattering (INS) and periodic density functional theory modeling (plane-wave DFT). According to a complementary experimental study, lovastatin shows no phase transitions down to cryogenic conditions, while a progressive, stepwise activation of several molecular motions is observed below room temperature. The molecular packing and intermolecular forces were analyzed theoretically, supported by a C-13 NMR study and further correlated with observed molecular dynamics. The NMR relaxation experiments combined with theoretical calculations disclose that molecular dynamics in solid lovastatin is related to methyl group motions and conformational disorder in the methylbutanoate fragment. This is precisely assigned and analyzed quantitatively from both experimental and theoretical perspectives. The neutron vibrational spectroscopy further corroborates that the methyl rotors have a classical nature. In addition to the intramolecular reorientations, the vibrational dynamics was analyzed with an emphasis on the low-wavenumber range. For the first time, the terahertz response of lovastatin was studied by confronting neutron and optical techniques and clearly illustrating their complementarity. The consistent picture of the molecular dynamics is provided, which may support further considerations on alternative drug formulations and the amorphization tendency in this important lipid-lowering drug.

Journal of Physical Chemistry B, 121(13), 2776-2787 (2017)

DOI: 10.1021/acs.jpcb.7b01090


Jenczyk J., Jurga S.

Complementary studies of NMR spin diffusion and atomic force microscopy - Structural characterization of diblock copolymers Due to their unique microphase structure copolymer systems have become important potential candidates for nanolitographic purposes. In order to properly design copolymeric templates a complete characterization of the phase separated system is required. Due to the fact that structural analysis of organic compounds remains demanding, especially when it comes to nanometer scale features such as interfacial spaces, there are very often at least two complementary experimental techniques employed to fully characterize observed morphologies. In this work diblock copolymers of poly (styrene)-b-poly (ethylene oxide) (PS-PEO) with three different molecular weights were investigated. Two different experimental methods were used: nuclear magnetic resonance spectroscopy (NMR) and atomic force microscopy (AFM). AFM topographic images of self-assembled polymer films enabled estimation of average interdomain distances, whereas the NMR spin diffusion experiment provided structural parameters related to stiff PS domains and interfacial space thickness. An application of two complementary methods enabled complete description of the studied morphologies and revealed substantial differences in polymer chain mobility between two distinct phases.

Polymer, 99, 90-96 (2016)

DOI: 10.1016/j.polymer.2016.07.006


Kiwilsza A., Pajzderska A., Mielcarek J., Jenczyk J., Wąsicki J.

Dynamical properties of nimodipine molecules confined in SBA-15 matrix The paper reports results of C-13 and H-1 ssNMR for nimodipine confined in mesopores of SBA-15 for the samples (i) containing nimodipine molecules inside and on the external surface of silica, (ii) containing nimodipine only inside pores forming an incomplete monolayer on the surface (iii) for bulk nimodipine. The measurements permitted comparison of the dynamics of nimodipine bulk and confined in pores. The confined nimodipine is in an amorphous state and has additional degrees of rotational freedom with respect to the bulk one. The height of the energy barrier related to the rotation of methyl groups in confined nimodipine is lower than in bulk nimodipine. The higher mobility of nimodipine molecules confined in silica pores can explain the higher release rate of nimodipine from silica matrix than dissolution rate of bulk drug.

Chemical Physics, 475, 126-130 (2016)

DOI: 10.1016/j.chemphys.2016.06.020


Drużbicki K., Pajzderska A., Kiwilsza A., Jenczyk J., Chudoba D., Jarek M., Mielcarek J., Wąsicki J.

In search of the mutual relationship between the structure, solid-state spectroscopy and molecular dynamics in selected calcium channel blockers Three isostructural 1,4-dihydropyridines (DHPs), namely, nifedipine, nitrendipine and nimodipine were selected to characterize their structure, intermolecular interactions and molecular dynamics. The studied samples were analyzed using powder X-ray diffraction (XRD), neutron (INS) and infrared spectroscopy (FT-IR) as well as solid-state nuclear magnetic resonance (NMR), where each technique was supported by the state-of-the-art theoretical calculations for solid-state. By combining multiple experimental techniques with advanced theoretical calculations we were able to shed light on the mutual relation between the structure, stabilizing intermolecular interactions and their spectral response. For the first time, unambiguous computationally-supported assignment of the most prominent spectral features in DHPs is presented to give a valuable support for polymorph screening and drug control. Molecular motions were interpreted in details, revealing that a dynamic reservoir of each compound is dominated by intra-molecular reorientations of methyl groups and large-amplitude oscillations in terminal chains. Our study successfully validates the realm of applicability of first-principles solid-state calculations in search of the mutual relation between the structure and spectroscopy in this important class of drugs. Such approach gives a first necessary step to gather combined structure-dynamics data on functionalized DHPs, which are of importance to better understand crystallization and binding tendency. The NMR relaxation experiments reveal that nitro groups significantly hinder the reorientation of methyl rotors and provide the first evidence of low-temperature methyl-group tunneling in DHPs, an intriguing quantum-effect which is to be further explored.

European Journal of Pharmaceutical Sciences, 85, 68-83 (2016)

DOI: 10.1016/j.ejps.2016.01.024


Jenczyk J., Coy E., Jurga S.

Poly(ethylene oxide)-block-polystyrene thin films morphology controlled by drying conditions and substrate topography Thin polymer films made of polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock copolymer were deposited via spin-coating technique on thermally reconstructed sapphire substrates in order to obtain self-assembled polymer matrices characterized by long range domain ordering. This approach, under specific solvent vapor annealing conditions, enabled us to fabricate polymer films exhibiting quasi long-range crystalline organization of hexagonally packed PEO cylinders aligned perpendicularly with respect to the substrate surface. In order to find an optimal conditions for thin film fabrication, the influence of moisture annealing process on polymer films morphology was examined. Different drying conditions revealed semicrystalline nature of poly(ethylene oxide) block. Consequently, apart from regular amorphous layers, various crystalline forms were also observed, including dendritic crystals, densely branched structures and square shaped single crystals. Presented data show how strongly the polymer film morphology depends on annealing conditions.

European Polymer Journal, 75, 234-242 (2016)

DOI: 10.1016/j.eurpolymj.2015.12.020   (Pobrane:  2018-04-04)


Pajzderska A., Drużbicki K., Kiwilsza A., Gonzalez M.A., Jenczyk J., Jurga S., Mielcarek J., Wąsicki J.

On the molecular dynamics in long-acting calcium channel blocker lacidipine: solid-state NMR, neutron scattering and periodic DFT study Molecular and vibrational dynamics of a new-generation lipophilic calcium channel blocker lacidipine (LCDP) are thoroughly explored by combining solid-state nuclear magnetic resonance (NMR) with high-flux quasi-elastic (QENS) and inelastic neutron scattering (INS) experiments. Contrary to the dynamically averaged C-13 CP/MAS NMR response, neutron vibrational spectroscopy confirms our previous findings on the thermodynamically stable structure. High-resolution low-wavenumber INS spectrum is reported and fully interpreted based on periodic density functional theory (DFT) calculations in the quasi-harmonic approximation, staying in excellent agreement with the experiment. The INS spectrum was found to be clearly dominated by CH3 torsional features, widely spread over the range of 5-35 meV. H-1 NMR relaxation indicates a molecular reorientation with different correlation times. The NMR relaxometry was further combined with an extended QENS study, providing a quantitative description of the intramolecular motions in terms of their activation barriers and correlation times, while their assignment was fully supported by theoretical analysis. While the internal dynamics of side-chain methyl groups can be described by rotation about the threefold-axes, the high-resolution QENS measurements give evidence of rotational tunneling of 2,6-methyl groups at low temperature. The vibrational analysis suggests that strong coupling of methyl librations with lattice modes promotes such an intriguing quantum effect.

RSC Advances, 6(71), 66617-66629 (2016)

DOI: 10.1039/c6ra07117a   (Pobrane:  2018-04-04)


Kadłubowski S., Matusiak M., Jenczyk J., Olejniczak M.N., Kozanecki M., Okrasa L.

Radiation-induced synthesis of thermo-sensitive, gradient hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate The gradient ("transient") systems are required for many biomedical applications, especially if the materials with different properties are to be joined without strong internal stresses. In this paper one step, radiation-induced synthesis of thermo-responsive hydrogels based on 2-(2-methoxyethoxy)ethyl methacrylate with gradient in crosslink density, has been presented. The influence of the monomer composition and synthesis procedure (irradiation dose and conditioning temperature) on the general properties of prepared gels has been discussed. It has been found that the properties of particular sections of the gel sample do not result from the differences in chemical structure, but from significantly different morphology. The explanation of the mechanism leading to gradient behavior of obtained gels has been proposed. The chemical structure of obtained products and morphology of synthesized hydrogels as well as general properties of products have been analyzed.

Radiation Physics and Chemistry, 100, 23-31 (2014)

DOI: 10.1016/j.radphyschem.2014.03.014


Pajzderska A., Drużbicki K., Gonzalez M.A., Jenczyk J., Peplińska B., Jarek M., Mielcarek J., Wąsicki J.

Experimental and solid-state computational study of structural and dynamic properties in the equilibrium form of temazepam Structural properties and rotational dynamics of methyl groups in the most stable form of temazepam were investigated by means of C-13 CP MAS NMR, quasielastic neutron scattering (QENS), and H-1 NMR spin lattice relaxation methods. The QENS and H-1 NMR studies reveal the inequivalency of methyl groups, delivering their activation parameters. The structural properties of the system were explored in frame of periodic density functional theory (DFT) computations, giving insight into the reorientational barriers and providing understanding of the solid-state NMR results. The theoretical computations are shedding light on the intermolecular interactions along their relation with particular asymmetric structural units.

Journal of Physical Chemistry B, 118(24), 6670-6679 (2014)

DOI: 10.1021/jp502609b


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)


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

The phase structure and molecular dynamics in poly(styrene-b-isoprene) diblock copolymer Molecular dynamics of polyisoprene, polystyrene and poly(styrene-b-isoprene) diblock copolymer has been studied by means of broadband dielectric and magnetic resonance spectroscopies. The measurements of dielectric permittivity as well as NMR second moment, spin-lattice relaxation times T(1) and T(1ρ), in wide range of temperature were performed. It was found that the copolymer exhibits all motions observed in the neat components i.e., three motions connected with polyisoprene blocks (segmental, normal-mode and methyl group rotation) and one (segmental) related to polystyrene blocks. The mutual interaction between polystyrene and polyisoprene chains leads to stiffening of polyisoprene blocks and loosening of polystyrene structure. The polyisoprene segmental and normal-mode motions were analyzed in terms of the Havriliak-Negami model and Vogel-Fulcher-Tamman (VFT) relation. Based on NMR spin-diffusion experiment the size of polystyrene domains in copolymer was evaluated and accounts to 9 nm.
(C) 2010 Elsevier B.V. All rights reserved.

Journal od Non-Crystalline Solids, 356(11-17), 582-588 (2010)

DOI: 10.1016/j.jnoncrysol.2009.06.046   (Pobrane:  2020-10-23)


Pielichowska K., Głowinkowski S., Lekki J., Biniaś D., Pielichowski K., Jenczyk J.

PEO/fatty acid blends for thermal energy storage materials. Structural/morphological teatures and hydrogen interactions Application of poly(ethylene oxide)-based materials as efficient thermal energy storage systems requires understanding of structural and morphological issues that govern the thermal transitions of the blends. Poly(ethylene oxide)/lauric acid and poly(ethylene oxide)/stearic acid blends show high values of heat of melting and heat of crystallisation which exceed theoretically determined values - it is a synergistic effect that is advantageous in terms of energy storage. The PEO blends were investigated by PLM, SEM, AFM, WAXD, SAXS and H-1 NMR techniques - PLM, SEM and AFM allows to observe regions, in which parallelly-packed crystals of fatty acid are present. WAXD results of PEO/fatty acid blends confirmed hindered crystallization of PEO in PEO/fatty acid blends and, finally, lower degree of polymer crystallinity. The NMR study shows that mixing of PEO and lauric acid results in an increase of PEO amorphous phase content in blends as compared to the pure PEO. From FTIR spectra, taken during melting and crystallization, it can be seen that for both investigated blends in the solid state there is only one maximum of band from v(C=O) (in position indicating that C=O groups are engaged in formation of hydrogen bonds), while in the liquid state there are two maxima - position of the first maximum is characteristic for v(C=O) vibrations of C=O groups that do not participate in formation of hydrogen bond, whereas position of the second maximum in the liquid state proves the presence of C=O groups involved in formation of hydrogen bonds. Solid state NMR analysis reveals no esterification reactions between PEO and fatty acid.
(C) 2008 Elsevier Ltd. All rights reserved.

European Polymer Journal, 44(10), 3344-3360 (2008)

DOI: 10.1016/j.eurpolymj.2008.07.047   (Pobrane:  2020-10-21)

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