Selective dissolution as a tool for detecting spatial variations in the metastability within lamellar polymer...

Area of Science:

• Materials Science
• Polymer Science
• Physical Chemistry

Background:

• Polymer crystal dissolution rates can vary significantly over time and space.
• Understanding these variations is crucial for controlling polymer properties.

Purpose of the Study:

• To investigate the relationship between polymer crystal growth kinetics and metastability.
• To elucidate how spatial variations in metastability are generated during crystal growth.

Main Methods:

• Utilized step-wise selective dissolution of low molecular weight poly(ethylene oxide) single crystals.
• Analyzed dissolution velocity along different crystal faces (rough vs. smooth).
• Determined detachment energies from the temperature dependence of dissolution.

Main Results:

• Dissolution velocity was constant along specific crystal faces but 5 times faster for rough faces compared to smooth faces.
• Detachment energies were 420 ± 40 kJ/mol for rough faces and 650 ± 50 kJ/mol for smooth faces.
• Rougher faces exhibit reduced inter-chain interactions.

Conclusions:

• Polymer crystal metastability is strongly linked to its growth kinetics.
• The progressive detachment of entire polymer chains is essential for crystal dissolution.
• Surface topography (roughness) significantly influences polymer crystal dissolution rates and stability.