Dresden 2020 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 85: Focus: Polymers under confinement I

CPP 85.1: Hauptvortrag

Donnerstag, 19. März 2020, 09:30–10:00, ZEU 222

Molecular view on polymers adsorbed on nanoparticle surfacesMozhdeh Abbasi1, Sol Mi Oh2, So Youn Kim2, and •Kay Saalwächter11Inst. f. Physik - NMR, Martin-Luther-Univ. Halle-Wittenberg, Halle (Saale), Germany — 2School of Energy and Chemical Engineering, UNIST, Ulsan, Republic of Korea

The reinforcement effect of nanoparticles in a polymer matrix is related to an interphase with modified properties [1]. Previous results support a consensus picture of adsorbed components with locally increased Tg and gradient zone of a few nm [2]. This talk focuses on more recent results, mostly obtained by proton low-resolution NMR as a probe of the segmental dynamics, that challenge the generality of this picture. In the system poly(ethylene oxide)-silica, we do find strongly immobilized (yet intrinsically mobile) components forming a layer of up to 2 nm thickness around the particles [3], but the layer thickness is temperature-independent and is governed by a non-equilibrium process in dependence of end groups [3] and preparation conditions [4], and also of the curvature of the particles. Spin-diffusion NMR experiments, which probe the size of nanometric domains with distinct mobility, indicate that the smooth-mobility-gradient picture of the ``glassy layer'' must be replaced by a scenario ruled by dynamic heterogeneities associated with the increased glass transition [5].

[1] A. Mujtaba et al., ACS Macro Lett. 2014, 3, 481 [2] A. Papon et al., Phys. Rev. Lett. 2012, 108, 065702 [3] Y. Golitsyn et al., J. Chem. Phys. 2017, 146, 203303 [4] S. M. Oh et al., Phys. Rev. Lett. 2019, 123, 167801 [5] H. Schneider et al., Macromolecules 2017, 50, 8598

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