title: Core@shell Poly(n-butylacrylate)@polystyrene Nanoparticles: Baroplastic Force-Responsiveness in Presence of Strong Phase Separation.
abstract: Poly(n-butylacrylate)@polystyrene nanoparticles behaving as a capsule-based sealing nanoadditive are synthesized through an optimized semicontinuous emulsion polymerization protocol. Solid state time-domain (1)H-NMR and (13)C magic angle spinning (MAS) NMR analysis suggest strong phase separation. Line width of (13)C resonances in cross polarization and single pulse experiment MAS-NMR spectra indicates that the peculiar mobility of each phase is preserved at the nanoscale. Atomic force spectroscopy (AFM) shows the permanence of spherical shape in absence of solvent (i.e., subsequent to strong capillary and surface forces) up to moderate external load, as well as the possibility of plastically deforming the polystyrene shell and ultimately triggering the nanoparticle flow at higher force loads. The breakdown characteristic of the nanoparticle shows for the first time baroplastic behavior on a single particle with precise biphasic core@shell morphology.
authors.affiliation: Department of Materials Science, University of Milan Bicocca, via R. Cozzi 55, Milan, 20125, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Bonetti
authors.affiliation: Department of Materials Science, University of Milan Bicocca, via R. Cozzi 55, Milan, 20125, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Farina
authors.affiliation: Department of Materials Science, University of Milan Bicocca, via R. Cozzi 55, Milan, 20125, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Mauri
authors.affiliation: Max-Planck Institut for Polymer Research, Ackermannweg 10, Mainz, D-55128, Germany.
authors.forename: Kaloian
authors.initials: K
authors.lastname: Koynov
authors.affiliation: Max-Planck Institut for Polymer Research, Ackermannweg 10, Mainz, D-55128, Germany.
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Butt
authors.affiliation: Max-Planck Institut for Polymer Research, Ackermannweg 10, Mainz, D-55128, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kappl
authors.affiliation: Department of Materials Science, University of Milan Bicocca, via R. Cozzi 55, Milan, 20125, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Simonutti
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000067493:Dynamic Light Scattering; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry*; D058105:Polymerization; D011137:Polystyrenes / Q000737:chemistry*; D044366:Transition Temperature
chemical_list: D000179:Acrylates; D011137:Polystyrenes; C032490:n-butyl acrylate
keywords: NMR; atomic force microscopy; baroplasticity; nanoparticles; sealing agents