Solution-state nanoconfined aggregation and microstructure evolution in blends of conjugated polymers and elastomers.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Wearable health monitoring demands stretchable and conformable electronic devices.
• Polymer semiconductors in elastomeric matrices offer high stretchability and charge transport.
• Understanding film formation is key to enhancing performance and scalability of polymer electronics.

Purpose of the Study:

• To investigate the film formation process of polymer semiconductor blends for wearable electronics.
• To elucidate the relationship between solution processing, thin-film morphology, and device performance.
• To identify optimal conditions for creating high-performing, stretchable polymer electronic composites.

Main Methods:

• Electron tomography to visualize film morphology.
• Cryogenic electron microscopy (cryo-EM) for high-resolution imaging of polymer aggregates.
• In situ grazing incidence wide-angle X-ray scattering (GIWAXS) to study crystallization.
• In situ ultraviolet-visible spectroscopy to monitor aggregation dynamics.

Main Results:

• DPPTT:SEBS blends form bundles of conjugated polymer nanofibers, unlike neat DPPTT films with irregular crystalline domains.
• Nanoconfined DPPTT nanofibers in blends originate from aligned 1D aggregates in solution.
• Crystallization initiates earlier in DPPTT:SEBS blends compared to neat DPPTT films.
• Blends exhibit interconnected, aligned nanofibers within the SEBS matrix, promoting efficient charge transport and mechanical strength.

Conclusions:

• Solution composition and processing significantly impact thin-film morphology in polymer composites.
• Aligned nanofibers in DPPTT:SEBS blends are crucial for achieving high-performing, stretchable electronic materials.
• This study provides insights for designing advanced polymer composites for flexible electronics and wearable devices.