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Updated: Jun 3, 2026
10:08
Fabrication of Large-area Free-standing Ultrathin Polymer Films
Published on: June 3, 2015
Nonequilibrium behavior of thin polymer films.
Katherine R Thomas1, Alexis Chenneviere, Günter Reiter
1Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
Summary
The solvent used to cast polystyrene films significantly impacts their viscosity and residual stress. Compact polymer chains in near-Theta solvents result in lower stresses compared to swollen chains in athermal solvents.
Area of Science:
- Polymer Science
- Materials Science
- Rheology
Background:
- Understanding the relationship between polymer chain conformation and film properties is crucial for materials design.
- Solvent properties during film casting can influence the final rheological behavior and internal stresses of polymer films.
Purpose of the Study:
- To investigate how casting solvent properties affect the rheological behavior of polystyrene films.
- To correlate polymer chain dimensions and entanglement with effective viscosity and residual stresses in thin films.
Main Methods:
- Fabrication of 100-nm-thick polystyrene films using various solvents.
- Application of an electric field to perturb the polymer melt surface and measure rheological properties.
- Analysis of film properties based on solvent quality and polymer chain conformation at vitrification.
Main Results:
- Effective viscosity and residual stresses are strongly dependent on casting solvent properties and solvent quality.
- More compact polymer chains (near-Theta solvent) lead to less entanglement and deformation, resulting in reduced stored stresses.
- A surface-near region with more deformed chains was observed during spin coating.
Conclusions:
- Casting solvent choice critically influences the final properties of polystyrene films.
- Polymer chain conformation at vitrification, dictated by solvent quality, governs entanglement and residual stress.
- Solvent vapor annealing offers a practical method for equilibrating spin-cast films.
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