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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 97: Nanostructures, Nanostructuring and Nanosized Soft Matter

CPP 97.1: Hauptvortrag

Donnerstag, 19. März 2020, 15:00–15:30, ZEU 255

Grain coarsening dynamics in cylinder-forming block copolymer thin films — •Michele Perego — CNR-IMM, Unit of Agrate Brianza, Italy

The all-organic polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) block-copolymer (BCP) thin films have been widely investigated for advanced lithographic applications, due to the possibility to promote perpendicular orientation of the nanodomains by easy neutralization of the surface with the appropriate random copolymer. In this BCP system, the Flory-Huggins parameter X is weakly dependent on T and, consequently, the segregation strength XN can be modulated by simply changing the degree of polymerization N. In this respect, thin films of cylinder forming PS-b-PMMA represent a perfect test system for fundamental investigations on the evolution of ordering in two-dimensional hexagonal lattices. In this talk, we will revise our experimental studies about the grain coarsening process in PS-b-PMMA thin films with different N. The evolution of the correlation length as a function of time follows a power law with a specific growth exponent for each value of N. The exponential decay of the growth exponent as a function of N is perfectly consistent with a diffusion limited mechanism of the grain coarsening process. Interestingly for very small N, growth exponent value 1/2 suggests that the lateral ordering process is guided by a curvature limited mechanism.