10.1021/nn900081u.s002 Violetta Olszowka Violetta Olszowka Markus Hund Markus Hund Volker Kuntermann Volker Kuntermann Sabine Scherdel Sabine Scherdel Larisa Tsarkova Larisa Tsarkova Alexander Böker Alexander Böker Electric Field Alignment of a Block Copolymer Nanopattern: Direct Observation of the Microscopic Mechanism American Chemical Society 2009 topological defects Block Copolymer Nanopattern Electric Field Alignment SFM film evolution orientational order parameter ABC terblock copolymer 2009-05-26 00:00:00 Media https://acs.figshare.com/articles/media/Electric_Field_Alignment_of_a_Block_Copolymer_Nanopattern_Direct_Observation_of_the_Microscopic_Mechanism/2854792 Using quasi<i>-in-situ</i> scanning force microscopy we study the details of nanopattern alignment in ABC terblock copolymer thin films in the presence of an in-plane electric field. Because of the surface interactions and electric field the lamellae are oriented both perpendicular to the plane of the film and parallel to the electric field. We identified two distinct defect types which govern the orientation mechanism. Ring-like (tori) and open-end defects dominate at the early stage of the orientation process, while mainly classic topological defects (disclinations and dislocations) are involved in long-range ordering at the late stages. Comparison of the time evolution of the defect density with the evolution of the orientational order parameter suggests that tori-defects are essential for the effective reorientation. Further, the quasi<i>-in-situ</i> SFM imaging allowed us to elucidate the influence of the electric field strength on the propagation velocity of the topological defects.