Microphase separation through competitive hydrogen bonding in self-assembled A-b-B/C diblock copolymer/homopolymer...

Area of Science:

• Polymer Science
• Materials Chemistry
• Supramolecular Chemistry

Background:

• Block copolymers and homopolymers form complex self-assembled structures.
• Hydrogen bonding is a key interaction in controlling material properties.
• Understanding phase behavior is crucial for designing advanced materials.

Purpose of the Study:

• To investigate microphase separation in A-b-B/C diblock copolymer/homopolymer complexes induced by competitive hydrogen bonding.
• To analyze the role of unequal interactions between polymer blocks and homopolymers in self-assembly.
• To establish structure-property relationships based on hydrogen bonding strength.

Main Methods:

• Infrared spectroscopy to quantify hydrogen bonding interactions and interassociation constants (K).
• Small-angle X-ray scattering (SAXS) to study phase behavior.
• Transmission electron microscopy (TEM) for morphological characterization.
• Random Phase Approximation (RPA) for theoretical analysis.

Main Results:

• Demonstrated microphase separation driven by differential hydrogen bonding between PVPh and P2VP (strong) versus PVPh and PMMA (weak).
• Observed a range of morphologies including lamellae, hexagonal cylinders, wormlike microdomains, and hierarchical structures.
• Correlated morphological transitions with copolymer concentration and the difference in interassociation constants (K).

Conclusions:

• Competitive hydrogen bonding is a powerful tool for controlling self-assembly and morphology in block copolymer/homopolymer systems.
• The disparity in interaction parameters (K) dictates the phase behavior and resulting nanostructures.
• This work provides a framework for designing materials with tailored morphologies through controlled hydrogen bonding.