Janus Polymer Single Crystal Nanosheet via Evaporative Crystallization.

Area of Science:

• Polymer Science
• Materials Science
• Crystallization Science

Background:

• Polymer crystallization is crucial for material properties.
• Controlling polymer chain folding during crystallization remains a challenge.
• Interfacial phenomena can influence self-assembly processes.

Purpose of the Study:

• To investigate the role of liquid/liquid interfaces in guiding polymer chain folding during crystallization.
• To synthesize uniform polymer single crystal films using evaporation-induced crystallization.
• To characterize the structural and surface properties of the resulting polymer single crystals.

Main Methods:

• Evaporation-induced crystallization of telechelic dicarboxyl end-functionalized poly(ε-caprolactone) (COOH-PCL-COOH) at a water/pentyl acetate interface.
• Formation of millimeter-scale, uniform polymer single crystal (PSC) films.
• In situ nanocondensation using environmental scanning electron microscopy (ESEM) for surface characterization.

Main Results:

• Liquid/liquid interface successfully guided polymer chain folding during crystallization.
• Uniform, millimeter-scale polymer single crystal films were produced.
• The polymer single crystal nanosheets exhibited a Janus structure with distinct surface wettability.
• Asymmetric surface properties were quantitatively confirmed by ESEM.

Conclusions:

• Liquid/liquid interfaces offer a novel strategy for controlling polymer crystallization and chain folding.
• The Janus structure of the polymer single crystals arises from the interfacial asymmetry.
• This method enables the production of uniform polymer single crystal films with tunable surface properties.