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arXiv · 2204.08855

Molecular rotors to probe the local viscosity of a polymer glass

Elham Mirzahossein·Marion Grzelka·Zhongcheng Pan·Begüm Demirkurt·Mehdi Habibi·Albert M. Brouwer·Daniel Bonn
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Abstract

We investigate the local viscosity of a polymer glass around its glass transition temperature using environment-sensitive fluorescent molecular rotors embedded in the polymer matrix. The rotors' fluorescence depends on the local viscosity, and measuring the fluorescence intensity and lifetime of the probe therefore allows to measure the local free volume in the polymer glass when going through the glass transition. This also allows us to study the local viscosity and free volume when the polymer film is put under an external stress. We find that the film does not flow homogeneously, but undergoes shear banding that is visible as a spatially varying free volume and viscosity.

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Elham Mirzahossein, Marion Grzelka, Zhongcheng Pan, Begüm Demirkurt, Mehdi Habibi, Albert M. Brouwer, Daniel Bonn. 2022-04-19. Molecular rotors to probe the local viscosity of a polymer glass. https://doi.org/10.1063/5.0087572

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