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Raman Spectroscopy Reveals Phase Separation in Imine-Based Covalent Adaptable Networks
Sybren K Schoustra1, Martijn H P de Heer Kloots1,2, Joris Posthuma1,2
1Laboratory of Organic Chemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
Macromolecules
|December 19, 2022
Summary
Researchers visualized phase separation in dynamic covalent polymer networks using Raman microscopy. This unexpected phase separation in adaptable networks improved material properties and can be controlled by altering network architecture.
Area of Science:
- Polymer Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Dynamic covalent bonds in polymer networks enable recyclable and adaptable materials.
- Understanding network architecture is key to controlling dynamic-mechanical properties of covalent adaptable networks (CANs).
- Phase separation is a potential strategy to tune material properties in CANs.
Purpose of the Study:
- To visualize phase separation in imine-based CANs using Raman confocal microscopy.
- To investigate the impact of phase separation on the thermal-mechanical properties of CANs.
- To explore methods for controlling phase separation in CANs.
Main Methods:
- Raman confocal microscopy was employed to visualize phase separation in imine-based CANs.
- Atomic force microscopy (AFM) was used to confirm the presence of phase-separated domains.
- CAN architecture was modified to control the extent of phase separation.
Main Results:
- Raman microscopy successfully visualized phase separation in imine-based CANs, even from miscible monomers.
- Phase-separated CANs exhibited enhanced thermal-mechanical properties, including higher crossover temperatures and increased elastic modulus.
- Phase separation could be suppressed or enhanced by modifying the CAN architecture, suggesting it is driven by π-π interactions.
Conclusions:
- Phase separation plays a significant role in the properties of CANs, even when components are initially miscible.
- Raman imaging is a suitable technique for visualizing phase separation in CANs.
- Controlling phase separation offers a pathway to tailor the dynamic-mechanical properties of covalent adaptable networks.
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