Specific features of defect structure and dynamics in the cylinder phase of block copolymers

Horvat, Andriana and Sevink, G. J. Agur and Zvelindovsky, Andrei and Krekhov, Alexei and Tsarkova, Larisa (2008) Specific features of defect structure and dynamics in the cylinder phase of block copolymers. ACS Nano, 2 (6). pp. 1143-1152. ISSN 1936-0851

Full content URL: http://pubs.acs.org/doi/abs/10.1021/nn800181m

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Specific features of defect structure and dynamics in the cylinder phase of block copolymers

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Abstract

We present a systematic study of defects in thin films of cylinder-forming block copolymers upon long-term thermal or solvent annealing. In particular, we consider in detail the peculiarities of both classical and specific topological defects, and conclude that there is a strong "defect structure- chain mobility" relationship in block copolymers. In the systems studied, representative defect configurations provide connectivity of the minority phase in the form of dislocations with a closed cylinder end or classical disclinations with incorporated alternative, nonbulk structures with planar symmetry. In solvent-annealed films with enhanced chain mobility, the neck defects (bridges between parallel cylinders) were observed. This type of nonsingular defect has not been identified in block copolymer systems before. We argue that topological arguments and 2D defect representation, sufficient for lamellar systems, are not sufficient to determine the stability and mobility of defects in the cylindrical phase. In-situ scanning force microscopy measurements are compared with the simulations based on the dynamic self-consistent mean field theory. The close match between experimental measurements and simulation results suggests that the lateral defect motion is diffusion-driven. In addition, 3D simulations demonstrated that the bottom (wetting) layer is only weakly involved into the structure ordering at the free surface. Finally, the morphological evolution is considered with the focus on the motion and interaction of the representative defect configuration. © 2008 American Chemical Society.

Keywords:Annealing, Block copolymers, Copolymerization, Copolymers, Cylinders (shapes), Defects, Imaging techniques, Knowledge based systems, Mean field theory, Microscopic examination, Phase stability, Plastic products, Polymers, Scanning tunneling microscopy, Solvents, Statistical mechanics, Thick films, Three dimensional computer graphics, Topology, 3-D simulations, American Chemical Society (ACS), Annealed films, Chain mobility, Co-polymer systems, Defect configurations, Defect motions, Defect representation, Disclinations, Experimental measurements, Free surfaces, In-situ, Minority phase, Morphological evolutions, Planar symmetry, Scanning force microscopy (SFM), Self consistent mean-field (SCMF), Simulation results, Solvent annealing, Structure and dynamics, Structure ordering, Systematic study, Topological defects, Defect structures, nanomaterial, polymer, article, chemical model, chemical structure, chemistry, computer simulation, conformation, crystallization, macromolecule, materials testing, methodology, nanotechnology, particle size, phase transition, surface property, ultrastructure, Computer Simulation, Macromolecular Substances, Models, Chemical, Models, Molecular, Molecular Conformation, Nanostructures, Surface Properties
Subjects:F Physical Sciences > F162 Polymer Chemistry
Divisions:College of Science > School of Mathematics and Physics
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ID Code:14924
Deposited On:17 Sep 2014 11:00

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