(1)H NMR and small-angle neutron scattering investigation of the structure and solubilization behavior of three-layer nanoparticles
Three-layer nanoparticles were prepared by radiation-induced polymerization of 1-10 g/L of methyl methacrylate dissolved in a 0.1 wt % D(2)O solution of polystyrene-poly(methacrylic acid) (PS-PMA) micelles. According to NMR and small-angle neutron scattering (SANS), most of the poly(methyl methacryl...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 20(2004), 25 vom: 07. Dez., Seite 11255-63 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , |
| Format: | Article |
| Langue: | English |
| Publié: |
2004
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| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article Research Support, Non-U.S. Gov't Micelles Polymethacrylic Acids Polystyrenes Protons polymethacrylic acid 25087-26-7 Polymethyl Methacrylate 9011-14-7 |
| Résumé: | Three-layer nanoparticles were prepared by radiation-induced polymerization of 1-10 g/L of methyl methacrylate dissolved in a 0.1 wt % D(2)O solution of polystyrene-poly(methacrylic acid) (PS-PMA) micelles. According to NMR and small-angle neutron scattering (SANS), most of the poly(methyl methacrylate) (PMMA) is adsorbed at the core-shell interface of the particles. A small fraction of shorter PMMA probably sticks to outer parts of the PMA chains. The absorption kinetics and equilibria of benzene and chloroform were studied by NMR and SANS time-resolved experiments. The diffusion front in the PS core is very narrow but quite broad in the PMMA sheet suggesting, thus, a less compact state of PMMA. According to SANS, the diffusion kinetics is almost independent of the PMMA sheet thickness. In contrast to it, the absorption capacity, reflected by both SANS and NMR, increases markedly with the PMMA content in the particle. The maximum amount of solubilized compound depends on its positive interaction with PMMA (expressed by the chi parameter) but is restricted by the growing interface tension between swollen PMMA and D(2)O. In accordance with this conclusion, a particle saturated with benzene can absorb chloroform only at the expense of a part of benzene expelled into the surrounding medium and vice versa. Starting with 10 g PMMA/L (10 times the weight of the original micelles), the particles become unstable when being swollen with a good solvent |
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| Description: | Date Completed 30.05.2006 Date Revised 15.11.2006 published: Print Citation Status MEDLINE |
| ISSN: | 1520-5827 |