Publications by authors named "U Keiderling"

Article Synopsis
  • Researchers synthesized block copolymers using Atom Transfer Radical Polymerization, varying the hydrophobic part's alkyl chain length and polymerization degree, which influenced micelle formation in water.
  • The copolymer aggregates were mixed with polycations like PDADMAC or q-chit to create Ionic-Polymer Complexes (IPECs), and their structure was analyzed using Static Light and Small Angle Neutron Scattering.
  • Results showed that block copolymer architecture impacts IPEC structure; short alkyl chains formed globular complexes, while longer chains led to the growth of existing micelles, with growth being more significant when using PDADMAC compared to q-chit.
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Here we report a thorough investigation of the microscopic and mesoscopic structural organization in a series of triphilic fluorinated room temperature ionic liquids, namely [1-alkyl,3-methylimidazolium][(trifluoromethanesulfonyl)(nonafluorobutylsulfonyl)imide], with alkyl = ethyl, butyl, octyl ([Cmim][IM], = 2, 4, 8), based on the synergic exploitation of X-ray and Neutron Scattering and Molecular Dynamics simulations. This study reveals the strong complementarity between X-ray/neutron scattering in detecting the complex segregated morphology in these systems at mesoscopic spatial scales. The use of MD simulations delivering a very good agreement with experimental data allows us to gain a robust understanding of the segregated morphology.

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Hypothesis: Ionic dendronic head groups possess very different structural features than simple surfactant head groups. Accordingly, their self-assembly behavior is expected to differ from that of conventional surfactants. The number of generations of the headgroup should play a particularly relevant role.

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The temperature response of micellar aggregates of poly(n-butyl acrylate)-b-poly(N-isopropylacrylamide)-carboxylic acid (PnBA-b-PNIPAM-COOH) end-functionalized diblock copolymers in aqueous solutions is investigated by small angle neutron scattering and light scattering techniques. The particular micellar aggregates present -COOH groups at their surface due to the molecular architecture of the block copolymer chains. Above the critical solution temperature micellar aggregation depends on the initial solution concentration, while at the highest polymer content intermicellar correlations are observed as a hard-sphere interaction intensity peak.

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We have investigated the influence of multiple scattering on the magnetic small-angle neutron scattering (SANS) from a Nd-Fe-B nanocrystalline magnet. We performed sample-thickness- and neutron-wavelength-dependent SANS measurements, and observed the scattering vector dependence of the multiple magnetic scattering. It is revealed that significant multiple scattering exists in the magnetic scattering rather than the nuclear scattering of Nd-Fe-B nanocrystalline magnet.

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