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Fabrication of Large-area Free-standing Ultrathin Polymer Films
Published on: June 3, 2015
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Dewetting Dynamics of Sheared Thin Polymer Films: An Experimental Study.
Anna Dmochowska1, Jorge Peixinho1, Cyrille Sollogoub1
1Laboratoire PIMM, CNRS, Arts et Métiers Institute of Technology, Cnam, HESAM Université, 75013 Paris, France.
ACS Macro Letters
|May 16, 2022
Summary
Shear significantly impacts the bursting of molten polymer films, causing holes to grow faster and change shape. This study models these effects to understand polymer processing instabilities.
Area of Science:
- Polymer Science
- Materials Science
- Fluid Dynamics
Background:
- Understanding polymer film behavior is crucial for manufacturing processes like multilayer coextrusion.
- Instabilities in polymer films can lead to defects and affect product quality.
Purpose of the Study:
- To experimentally investigate the effect of shear on the bursting dynamics of molten ultrathin polymer films.
- To develop a model that explains shear-induced changes in dewetting hole growth and morphology.
Main Methods:
- Utilized an optical microscope with a shearing hot stage to monitor dewetting dynamics in real-time.
- Applied various shear rates to ultrathin polymer films embedded in an immiscible matrix.
- Developed a model incorporating capillary forces, viscous dissipation, and shear thinning.
Main Results:
- Observed that shear modifies the circularity of dewetting holes, leading to an ellipsoid shape.
- Demonstrated a rapid increase in hole growth speed with increasing shear rate.
- The proposed model accurately captures experimental data, including faster dynamics parallel to the shear direction.
Conclusions:
- Shear flow significantly alters the bursting behavior of molten polymer films.
- The developed model provides insights into shear-thinning effects on dewetting instabilities.
- Findings are applicable to optimizing processes involving layered polymeric structures.
