Synthesis, Processing, and Characterization of Helical Polypeptide Rod-Coil Mixed Brushes

Area of Science:

• Polymer Chemistry
• Surface Science
• Materials Science

Background:

• Mixed polymer brushes offer tunable surface properties.
• Controlling the self-assembly of polymer brushes is crucial for advanced materials.
• Understanding the interplay between different polymer architectures is essential.

Purpose of the Study:

• To investigate the morphological and orientational effects of coil-type vinyl polymer brushes on rod-type polypeptide brushes.
• To analyze the impact of solvent quenching on the structure of mixed polymer brushes.
• To determine how the molecular weight of coil-type polymers influences the properties of mixed brushes.

Main Methods:

• Synthesis of mixed polymer brushes via sequential surface-initiated ring-opening polymerization (SI-ROP) and surface-initiated atom transfer radical polymerization (SI-ATRP).
• Characterization of surface morphology, film thickness, and orientation before and after solvent quenching (chloroform, acetone).
• Analysis of changes with varying coil-type polymer molecular weights.

Main Results:

• Before solvent quenching, coil-type brushes promoted polypeptide vertical orientation and increased film thickness, but random orientation.
• After solvent quenching, polypeptide brushes formed perpendicular conical bundles, with coil-type brushes limiting their movement and arrangement.
• Increased coil-type polymer molecular weight led to observable changes in film thickness, rod orientation, morphology, and wettability.

Conclusions:

• Sequential polymerization enables the creation of complex mixed polymer brush architectures.
• Solvent quenching significantly alters the self-assembly and orientation of polypeptide brushes within mixed systems.
• The molecular weight of the coil-type component is a critical factor in controlling the final properties of these mixed polymer brushes.