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The timescale of spinodal dewetting at a polymer/polymer interface
A M Higgins1, M Sferrazza, R A L Jones
1Department of Physics and Astronomy, University of Sheffield, The Hicks Building, Sheffield S3 7RH, UK. a.higgins@shef.ac.uk
The European Physical Journal. E, Soft Matter
|March 11, 2004
Summary
Spinodal dewetting in polymer blends was studied using neutron reflectivity. The research found that thin film viscosity scaling matches bulk behavior, but absolute values are lower due to interface slippage.
Area of Science:
- Polymer Physics
- Materials Science
- Surface Science
Background:
- Spinodal dewetting is a critical process in thin polymer films.
- Understanding dewetting dynamics is essential for controlling material properties.
- Polymer blend interfaces present unique challenges in studying dewetting.
Purpose of the Study:
- To investigate the dynamics of spinodal dewetting in poly(methyl-methacrylate) (PMMA) thin films on polystyrene (PS) substrates.
- To determine the characteristic growth times of the dewetting process as a function of polymer molecular weight.
- To probe the scaling of PMMA thin film viscosity with temperature and molecular weight.
Main Methods:
- In situ neutron reflectivity was employed to monitor dewetting.
- Analysis of interface and surface roughness development provided characteristic growth times.
- Experiments were conducted across varying polymer molecular weights and temperatures.
Main Results:
- Characteristic dewetting growth times were measured and correlated with polymer molecular weight.
- The scaling of PMMA thin film viscosity with temperature and molecular weight was found to reflect bulk behavior.
- Observed absolute viscosity values were lower than bulk values, suggesting interfacial slippage.
Conclusions:
- Spinodal dewetting dynamics in polymer blends are influenced by molecular weight.
- Thin film viscosity scaling in this system is consistent with bulk polymer properties.
- Interfacial slippage at the polymer/polymer interface likely contributes to reduced absolute viscosity values.