Fick Diffusion Coefficients of Polystyrene Oligomers with Dissolved Blowing Agents by Dynamic Light Scattering and Molecular Dynamics Simulations

Schmidt P, Hewa Kankanamge CJK, Jander JH, Vergadou N, Economou I, Klein T, Fröba AP

Publication Type: Journal article

Journal

Macromolecules American Chemical Society

Book Volume: 58

Pages Range: 10238-10252

Journal Issue: 19

DOI: 10.1021/acs.macromol.5c01713

Abstract

This work aims at establishing a fundamental understanding of mass diffusion in blowing-agent-loaded polymer melts. For this, dynamic light scattering (DLS) and molecular dynamics (MD) simulations were developed and applied for a comprehensive investigation of diffusive mass transfer in such systems. For this, for the first time, a full characterization of mixtures consisting of well-defined and nearly monodisperse oligomers with dissolved blowing agents was performed by the determination of their density and diffusivities as well as the study of their liquid structure. In this context, the influence of the molecular characteristics of the oligomer, including its chain length, and the solutes on the Fick diffusion coefficient D11, self- and Maxwell-Stefan diffusion coefficients, and the thermodynamic factor, as well as the relationships between the different diffusion coefficients were investigated for the first time in mixtures of polystyrene (PS) oligomers with dissolved nitrogen (N2), carbon dioxide (CO2), or 1,1,1,2-tetrafluoroethane (R134a) at process-relevant conditions. For MD simulations, a new force field (FF) was developed particularly considering dihedral potentials, which can-in contrast to previously reported FFs for PS-accurately predict the influence of the chain length of oligomers on their thermophysical properties. For its validation, DLS was applied to determine D11in mixtures of oligomers with different blowing agents. Combining DLS and MD simulations a comprehensive understanding of the influence of the molecular characteristics of the solute and the solvent on diffusive mass transport was developed. It is demonstrated that the studied mixtures exhibit a nonideal behavior, indicating that the assumption of infinite dilution often adopted in the literature is not applicable. Moreover, for D11, a characteristic asymptotic behavior with increasing chain length of the PS oligomers was revealed.

Authors with CRIS profile

Patrick Schmidt Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Chathura Jayan Kankanamge Hewa Kankanamge Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Julius Jander Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Tobias Klein Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP) Andreas Paul Fröba Institute of Advanced Optical Technologies - Thermophysical Properties (AOT-TP)

Involved external institutions

National Centre for Scientific Research (NCSR) "Demokritos" GR Greece (GR)

How to cite

APA:

Schmidt, P., Hewa Kankanamge, C.J.K., Jander, J.H., Vergadou, N., Economou, I., Klein, T., & Fröba, A.P. (2025). Fick Diffusion Coefficients of Polystyrene Oligomers with Dissolved Blowing Agents by Dynamic Light Scattering and Molecular Dynamics Simulations. Macromolecules, 58(19), 10238-10252. https://doi.org/10.1021/acs.macromol.5c01713

MLA:

Schmidt, Patrick, et al. "Fick Diffusion Coefficients of Polystyrene Oligomers with Dissolved Blowing Agents by Dynamic Light Scattering and Molecular Dynamics Simulations." Macromolecules 58.19 (2025): 10238-10252.

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