A. Lattice Transition of Sphere Forming Block Copolymer

In sphere-forming block copolymers' self-assembly, their optimal packing structure is defined by the combination of entropic and enthalpic contributions, and these can be changed by controlling external environments like temperature, solvent quality, and else. We could observe the structural transition in BCP thin films under solvent annealing condition, and conduct in-depth analysis based on images.

B. Morphology Transformation of Block Copolymer Surface Micelles

Amphiphilic block copolymers (BCPs) can form 2-D confined micellar structures, called BCP surface micelles, through self-assembly at the air-water interface. These BCP surface micelles can transform into diverse nanostructures with direct immersion in specific solvents. To investigate this phenomena, we conduct experiments by controlling various experimental parameters, and further discuss how these parameters alter the rearrangement kinetics of the surface micelles. Based on the understanding of complex chain dynamics upon solvent immersion, our research provides a new strategy to fabricate a uniform array of diverse BCP nanopatterns.

Representative paper

Constructing a Comprehensive Nanopattern Library through Morphological Transitions of Block Copolymer Surface Micelles via Direct Solvent Immersion (Small, 2024)

C. Morphology Transformation of Metal-Infiltrated Block Copolymer Thin Films

Disordered structures in nanoscale have received increasing interest owing to their unique capability to localize wave-like quasiparticles – a renowned phenomenon known as Anderson localization. We present a methodology to construct such disordered structures by deliberately introducing controlled degree of defects into a single crystalline hexagonal array built on a sphere-forming block copolymer thin film. Various tunable parameters, including but not limited to relative ratio of different metal precursors incorporated into the core blocks, are proposed to broaden the spectrum of disorder. Our research potentially offers a platform for designing and engineering disordered systems which could mediate quasiparticle localization.

After the self-assembly of block copolymers, metals can be infiltrated into either of the two domains. These metal infiltrated structures can be transformed into various structures via thermal annealing. Depending on the original film's properties (e.g., defect density), the resulting films have different structures. We investigate the morphology alteration of such BCP films by gaining insight into the kinetics and thermodynamics of metal infiltrated BCP chains. Moreover, we seek for new avenues for the fabrication of nanodevices utilizing the large area production of such unique structures. 

Universal Interfacial Control through Polymeric Nanomosaic Coating for Block Copolymer Nanopatterning