Density mismatch in thin diblock copolymer films

Interference microscopy on thin diblock copolymer films

2014 At equilibrium thin films of symmetric diblock copolymers exhibit a morphology where the lamellar microdomains are oriented parallel to the external surfaces. Interference microscopy has been used to investigate this orientation which results in a quantization of the film thickness. Solution cast films of the symmetric polystyrene/polymethylmethacrylate P(S-b-MMA) diblock copolymers exhibi...

Solvent-induced novel morphologies in diblock copolymer blend thin films.

We report the morphology and phase behaviors of blend thin films containing two polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymers with different blending compositions induced by a selective solvent for the PMMA block, which were studied by transmission electron microscopy (TEM). The neat asymmetric PS-b-PMMA diblock copolymers employed in this study, respectively coded as a...

Interfacial profiles of mismatched lamellae in thin diblock copolymer films

Pattern formation mechanisms in sphere-forming diblock copolymer thin films

The order-disorder transition of a sphere-forming block copolymer thin film was numerically studied through a Cahn-Hilliard model. Simulations show that the fundamental mechanisms of pattern formation are spinodal decomposition and nucleation and growth. The range of validity of each relaxation process is controlled by the spinodal and order-disorder temperatures. The initial stages of spinodal...

Crystallization in diblock copolymer thin films at different degrees of supercooling.

The crystalline structures in thin films of polystyrene-b-poly(ethylene oxide) (PS-b-PEO) diblock copolymers were studied in dependence on the degree of supercooling. Atomic force microscopy showed that the crystalline domains (lamellae) consist of grains, which are macroscopic at low and intermediate degrees of supercooling, but of submicrometer size for strong supercooling. Using grazing-inci...