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Excluded volume model for the reduction of polymer diffusion into nanocomposites
Jeffrey S Meth1, Sangah Gam, Jihoon Choi
1DuPont Nanocomposite Technologies, Central Research & Development, E. I. DuPont de Nemours & Co., Inc. , Route 141, Wilmington, Delaware 19880-0400, United States.
The Journal of Physical Chemistry. B
|August 28, 2013
Summary
A new model explains how polymer diffusion slows in nanocomposites due to excluded volume effects. It accurately predicts reduced diffusion coefficients at low particle loadings without adjustable parameters.
Area of Science:
- Polymer Science
- Materials Science
- Statistical Mechanics
Background:
- Polymer chain diffusion is crucial for material properties.
- Understanding diffusion in nanocomposites is complex.
- Excluded volume effects significantly impact polymer mobility.
Purpose of the Study:
- To develop an analytic model for polymer diffusion in nanocomposites.
- To account for excluded volume effects using a cylinder model.
- To validate the model against experimental data.
Main Methods:
- Modeling nanocomposites as an ensemble of cylinders.
- Equating polymer diffusion reduction to sphere-cylinder diffusion.
- Using statistical mechanics for particle packing and cylinder diameter distribution.
Main Results:
- A master curve for the reduced diffusion coefficient was derived.
- The model shows good agreement with recent tracer diffusion data.
- No adjustable parameters were needed for model validation.
Conclusions:
- The analytic model effectively captures polymer diffusion reduction in nanocomposites.
- Excluded volume effects are accurately represented by the cylinder ensemble.
- The model provides a predictive tool for polymer nanocomposite design.
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