Thermoresponsive polymer assemblies via variable temperature liquid-phase transmission electron microscopy and small...

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Thermoresponsive polymers exhibit significant changes in properties with temperature variations.
• Understanding nanoscale assembly dynamics is crucial for designing advanced materials.
• Block copolymers offer tunable properties for self-assembly applications.

Purpose of the Study:

• To investigate the phase transitions and nanoscale assembly dynamics of thermoresponsive polymers.
• To gain mechanistic insight into thermally-induced morphological transformations.
• To develop and validate a multimodal approach for imaging solvated polymer structures.

Main Methods:

• Variable temperature liquid-cell transmission electron microscopy (VT-LCTEM) to visualize nanoscale structures in solution.
• Variable temperature small-angle X-ray scattering (VT-SAXS) to analyze polymer morphology and phase behavior.
• Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) for polymer survival assessment.

Main Results:

• Direct imaging of thermally-induced nanoscale transitions in poly(diethylene glycol methyl ether methacrylate) (PDEGMA)-based block copolymers.
• Correlation of VT-SAXS and VT-LCTEM data provided insights into transient intermediates during morphological changes.
• Observation of temperature-triggered formation and slow relaxation of core-shell particles with internal microphase separation.

Conclusions:

• The multimodal approach (VT-LCTEM, VT-SAXS, MALDI-IMS) is effective for studying polymer phase transitions and nanoscale dynamics.
• This strategy allows direct visualization of solvated nanostructures and their thermal responses.
• The findings offer a generalizable method for characterizing polymer self-assembly and transitions.