ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (4)
  • *Base Pairing  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Structure and dynamics of polyelectrolyte-surfactant complexes as revealed by solid state NMR (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 2713-2727 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 13C-CP/MAS-NMR (cross-polarization magic angle spinning), 2D-WISE (wideline separation experiment) and 1H-spin diffusion experiments allow to gain new insight into the structure and dynamics of solid polyelectrolyte-surfactant complexes, a material with pronounced mesophase formation. Experiments were performed on two different complexes of polystyrene sulfonate and octadecyltrimethylammonium or tetradecyltrimethylammonium counterions, PSS-C18 and PSS-C14. The strong mobility differences between the ionic and alkyl phase in the lamellar complex PSS-C18 are reflected in the NMR behavior: in the surfactant tails, a mobility gradient towards the terminal methyl group is observed. This fact as well as a high content of gauche conformations suggest a non-interdigitating morphology of the tails at room temperature. The behavior changes during cooling below an endothermic transition centered at 255 K where a high trans content and a homogenization of the side chain dynamics is observed. We attribute this transition which is invisible in the X-ray experiments to the formation of a highly transoid, interdigitated phase of the surfactant tails which is however not crystallized in a classical sense. 1H-spin diffusion experiments allow to estimate the distance between mobile and immobile regions of the sample. For the complex PSS-C14, the length scale determined by NMR is essentially that of the primary lamellar structure. For PSS-C18, a characteristic length of the density fluctuations within the proposed undulated lamellar structure is estimated.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021970910
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Band-forming centerpieces for the analytical ultracentrifuge (1965)
    New York : Wiley-Blackwell
    Biopolymers 3 (1965), S. 481-489 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three types of band-forming centerpieces useful in band centrifugation in the analytical ultracentrifuge are described. The mode of filling and the advantages and disadvantages of each type are discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1965.360030409
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Interaction between polybrominated flame retardants and high impact polystyrene (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 715-720 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Mixtures of two crystalline brominated aromatic flame retardants with a surrounding polymer were studied by differential scanning calormetry, dynamic mechanical analysis (DMA), wide angle X-ray scattering, and solid-state NMR spectroscopy. 1,2-Bis(tet-rabromophthalimide)ethane (I) and decabromodiphenyloxide (II) were evaluated in high impact polystyrene (HIPS). Additive I exhibits all the properties of an inert filler. The crystalline structure with respect to the pure material remains unchanged within the polymer. Concerning the HIPS matrix, a slight rise in the melt viscosity and a reduced impact strenth as compared to the base resin was observed. In contrast, additive II is miscible with the HIPS matrix and dissolves completely. This leads to an increase of the glass transition temperature of the polybutadiene phase as revealed by solid-state NMR spectroscopy and DMA. The impact resistance of the HIPS matrix is less affected by additive II than by additive I. No interactions were noted with the PS phase at températures up to the glass transition. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Spherulite size effects in linear polyethylene (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 12 (1974), S. 819-821 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.180120416
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    facet.materialart.
    Unknown
    Efficient deactivation of a model base pair via excited-state hydrogen transfer (2004)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2004-12-04
    Description: We present experimental and theoretical evidence for an excited-state deactivation mechanism specific to hydrogen-bonded aromatic dimers, which may account, in part, for the photostability of the Watson-Crick base pairs in DNA. Femtosecond time-resolved mass spectroscopy of 2-aminopyridine clusters reveals an excited-state lifetime of 65 +/- 10 picoseconds for the near-planar hydrogen-bonded dimer, which is significantly shorter than the lifetime of either the monomer or the 3- and 4-membered nonplanar clusters. Ab initio calculations of reaction pathways and potential-energy profiles identify the mechanism of the enhanced excited-state decay of the dimer: Conical intersections connect the locally excited 1pipi* state and the electronic ground state with a 1pipi* charge-transfer state that is strongly stabilized by the transfer of a proton.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schultz, Thomas -- Samoylova, Elena -- Radloff, Wolfgang -- Hertel, Ingolf V -- Sobolewski, Andrzej L -- Domcke, Wolfgang -- New York, N.Y. -- Science. 2004 Dec 3;306(5702):1765-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max Born Institute Berlin, Max-Born-Strasse 2a, D-10247 Berlin, Germany. schultz@mbi-berlin.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15576616" target="_blank"〉PubMed〈/a〉
    Keywords: Aminopyridines/*chemistry ; *Base Pairing ; Chemistry, Physical ; DNA/*chemistry ; Dimerization ; Hydrogen/*chemistry ; Hydrogen Bonding ; Mass Spectrometry ; Models, Chemical ; Physicochemical Phenomena ; Protons ; Thermodynamics ; Ultraviolet Rays
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...