Long-Range Ordered Crystallization Structure in the Micromolded Diblock Copolymer Thin Film.

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Block copolymers self-assemble into ordered nanostructures.
• Controlling crystallization in thin films is crucial for device applications.
• Confined crystallization offers a route to ordered polymer morphologies.

Purpose of the Study:

• To investigate the confined crystallization of poly(butadiene)-block-poly(ε-caprolactone) (PB-b-PCL) diblock copolymer thin films.
• To understand the influence of geometric confinement on polymer crystallization.
• To explore micromolding as a technique for nanoscale control of block copolymer crystallization.

Main Methods:

• Micromolding of PB-b-PCL diblock copolymer thin films.
• Electron diffraction (ED) analysis.
• Grazing-incidence X-ray diffraction (GIXD) experiments.

Main Results:

• Observed long-range ordering of poly(ε-caprolactone) (PCL) crystals.
• PCL crystallographic b-axis aligned parallel to the channel long-axis.
• Geometric confinement directed PCL crystal growth along the channel.
• Substrate-induced ordering restricted in-plane diffusion and prevented cross-channel crystallization.

Conclusions:

• Micromolding effectively confines block copolymer crystallization.
• Geometric effects are dominant in directing PCL crystal orientation.
• This method provides a promising approach for tailoring nanoscale crystallization in thin films.