Horvat, Andriana, Sevink, G. J. Agur, Zvelindovsky, Andrei V., 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
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Official URL: http://dx.doi.org/10.1021/nn800181m
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 configurations.
|Uncontrolled Keywords (separate with ;):||block copolymers; thin films; defect structure and dynamics; nanostructured soft matter|
|Subjects:||Q Science > QC Physics|
|Schools:||College of Science and Technology > School of Physical Sciences and Computing|
|Deposited By:||Malgosia Bagot|
|Deposited On:||28 Jun 2012 11:15|
|Last Modified:||11 Mar 2014 09:49|
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