Molecular Mobility in Oriented and Unoriented Membranes Based on Poly[2-(Aziridin-1-yl)ethanol]

Area of Science:

• Polymer Science
• Materials Science
• Supramolecular Chemistry

Background:

• Dendronized polymers offer unique structural and functional properties.
• Poly[2-(aziridin-1-yl) ethanol] (PAZE) is a versatile polymer backbone for modification.
• Liquid crystalline dendrons can impart specific self-assembly and thermal behaviors.

Purpose of the Study:

• To synthesize and characterize unoriented and oriented membranes from chemically modified PAZE.
• To investigate the impact of dendritic groups and orientation on polymer membrane properties.
• To explore the potential of these membranes for selective ionic transport.

Main Methods:

• Chemical modification of PAZE with a specific dendron.
• Differential Scanning Calorimetry (DSC) for thermal transitions.
• X-ray Diffraction (XRD) for structural analysis.
• Solid-state Nuclear Magnetic Resonance (CP-MAS NMR) for molecular mobility.
• Dielectric Thermal Analysis (DETA) for relaxation dynamics.

Main Results:

• Characterization revealed crystallization tendencies, molecular mobility of substituents, and clearing transitions.
• Membrane orientation influenced molecular motion, particularly in fully substituted PAZE.
• Fragility, free volume, and thermal expansion coefficients were linked to orientation and dendritic group addition.
• PAZE-based membranes exhibited controlled supramolecular order and macroscopic mobility.

Conclusions:

• Dendritic modification and thermal orientation effectively control the properties of PAZE-based membranes.
• These membranes possess a balance of order and mobility crucial for ionic transport.
• The developed membranes show promise for applications requiring selective ion conduction.