Well-Defined Oxide Core-Poly(vinyl pyrrolidone) Shell Nanoparticles: Interactions and Multi-Modal Glass Transition Dynamics at Interfaces |
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| Authors: | Vladimir Bershtein Vladimir Gun'ko Larisa Egorova Natalia Guzenko Eugene Pakhlov Valery Ryzhov Vladimir Zarko |
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| Institution: | 1. Ioffe Physical -Technical Institute, Russian Academy of Sciences, 26 Politechnicheskaya str, St.-Petersburg 194021, Russia;2. Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 17 General Naumov str, Kiev 03164, Ukraine |
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| Abstract: | Interfacial interactions and dynamics were studied in silica and alumina core-poly(vinyl pyrrolidone) (PVP) shell nanoparticles with different shell thicknesses starting from 1-2 nm (monolayer); their geometry and structural organization were comprehensively characterized by several techniques. Far- and mid-IR spectroscopy, combined with DSC activation analysis of the glass transition, allowed to register hydrogen bonding and Lewis/Brønsted interactions, and the multi-modal glass transition dynamics in PVP nanoshells, as well as their interrelationship. For PVP monolayer, only a few “abnormal” modes constituted glass transition which covered the temperature range from 80 to 230 °C, with varying the activation energy by an order of magnitude. |
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| Keywords: | calorimetry core-shell nanoparticles glass transition infrared spectroscopy interfaces |
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