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001-es BibID:	BIBFORM097682
Első szerző:	Binder, Wolfgang H.
Cím:	Magnetic and Temperature-Sensitive Release Gels from Supramolecular Polymers / Wolfgang H. Binder, Laura Petraru, Thomas Roth, Peter W. Groh, Viktória Pálfi, Sandor Keki, Bela Ivan
Dátum:	2007
ISSN:	1616-301X
Megjegyzések:	Supramolecular gels consisting of trivalent polyisobutylene and bivalent poly(ethylene oxide) are generated. Strong hydrogen bonding interactions, affixed to the end-group moieties of the respective polymers (binding constant Kassn?=?105?M?1), serve as molecular glue, leading to the formation of weak gels. Two different gels were prepared: one, with a short telechelic poly(ethylene glycol) (PEG) segment (gel?A), and one with a longer PEG segment (number-average molecular weight Mn?=?2000?g?mol?1) (gel?B). Both gels show a significant increase in viscosity upon mixing of the two polymeric components, with a lag time of several minutes, indicative of nucleation mechanisms as the formation principle. However, only gel?A displays classical gel-like behavior, with a loss modulus G· larger than the storage modulus Gı after formation. Both gels display microphase-separated behavior with a spacing between 4?5?nm as probed via small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) measurements. The incorporation of magnetic nanoparticles (Fe2O3; radius r?=?3.5?nm) is successfully achieved, generating new magnetic gels with strongly thermoresponsive properties, displaying a strong temperature-dependent release profile of included dye molecules. Magnetic measurements indicate a superparamagnetic behavior of the incorporated nanoparticles, prospecting the application as magneto-sensitive delivery gels for pharmaceutical purposes.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Advanced Functional Materials. - 17 : 8 (2007), p. 1317-1326. -
További szerzők:	Petraru, Laura Roth, Thomas Groh, Peter W. Pálfi Viktória Kéki Sándor (1964-) (polimer kémikus) Iván Béla
Pályázati támogatás:	T46759 OTKA
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM010304
Első szerző:	Nagy Lajos (vegyész)
Cím:	Dopant-Assisted Atmospheric Pressure Photoionization Mass Spectrometry of Polyisobutylene Derivatives Initiated by Mono- and Bifunctional Initiators / Lajos Nagy, Viktória Pálfi, Mijid Narmandakh, Ákos Kuki, Andrea Nyíri, Béla Iván, Miklós Zsuga, Sándor Kéki
Dátum:	2009
Megjegyzések:	Nine polyisobutylene (PIB) derivatives with different end groups (chlorine, vinyl, isobutenyl, 2,2-diphenylvinyl, and carboxyl) and molecular weights (1000 to 4500 g/mol), initiated by monofunctional and aromatic bifunctional initiators were studied by atmospheric pressure photoionization mass spectrometry (APPI-MS) in both the negative and the positive ion modes. Consistent with previous findings, negative ion APPI-MS revealed end-group identities through the formation of PIB adducts with chloride ions formed in situ from a chlorinated solvent (e.g., CCl4) in the presence of a dopant (toluene). In positive ion mode, considerable fragmentation of these PIB derivatives was observed, rendering end-group determinations very difficult. The Mn values obtained by APPI(-)-MS were considerably lower than those determined by SEC for PIB derivatives with Mn higher than 2000 g/mol. PIBs containing carboxyl termini can undergo collision-induced dissociation, yielding structurally important product ions. The resulting APPI-MS/MS intensities were found to reflect the "arm-length" distribution for PIBs with bifunctional aromatic moieties. In positive ion mode, [M+COCl]+ adducts were observed for PIBs with an aromatic initiator moiety. The origin of the COCl+ species is also discussed.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Polyisobutylene APPI-MS mass spectrometry chloride ion attachment
Megjelenés:	Journal of the American Society for Mass Spectrometry. - 20 : 12 (2009), p. 2342-2351. -
További szerzők:	Pálfi Viktória Narmandakh, Mijid Kuki Ákos (1966-) (villamosmérnök) Nyíri Andrea Iván Béla Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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