Beyond Orientation: The Impact of Electric Fields on Block Copolymers

Abstract

Since the fi rst report on electric fi eld-induced alignment of block copolymers (BCPs) in 1991, electric fi elds have been shown not only to direct the orientation of BCP nanostructures in bulk, solution, and thin fi lms, but also to reversibly induce order-order transitions, affect the order-disorder transition temperature, and control morphologies' dimensions with nanometer precision. Theoretical and experimental results of the past years in this very interesting fi eld of research are summarized and future perspectives are outlined. C. Liedel , C. W. Pester , A. Böker Lehrstuhl für Makromolekulare Materialien und Oberfl ächen, DWI an der RWTH Aachen e.Clemens Liedel studied chemistry and macromolecular science (in the framework of the Elite Network of Bavaria) at Bayreuth University and recieved his diplomas in 2008 and 2010, respectively. Since 2008, he has been working on his Ph.D. degree in Bayreuth and Aachen in the group of Prof. A. Böker with an included research period at the University of California Santa Barbara (UCSB) in the group of Prof. E. J. Kramer. The topic of his current work is block copolymers and composite materials in thin fi lms exposed to electric fi elds. Christian W. Pester received his diploma in polymer and colloidal chemistry from Bayreuth University in 2009. The topic of his diploma thesis was electric-fi eld induced alterations of domain spacings. He then entered RWTH Aachen University and is pursuing his Ph.D. degree under the supervision of Prof. A. Böker. His current research interest focuses on the study of block copolymers in electric fi elds by small-angle scattering methods. Alexander Böker is a Full Professor at RWTH Aachen University for Macromolecular Materials and Surfaces and Co-Director of the DWI an der RWTH Aachen e.V. He studied chemistry at Cornell University and the University of Mainz, Germany, where he received his diploma in chemistry in 1999. In 2002, he completed his Ph.D. in physical and macromolecular chemistry at the University of Bayreuth. From 2002 to 2004, he worked with Thomas P. Russell at the University of Massachusetts, Amherst. His main research interests include guided self-assembly of block copolymer and nanoparticle systems, and their control via external fi elds.

Order-Disorder Transition and Alignment Dynamics of a Block Copolymer Under High Magnetic Fields byIn SituX-Ray Scattering

“…Pronounced field-induced changes in transition temperatures can drive selective melting whereby domains which are not in the energy minimizing orientation are destabilized, and thus shrink, or ''melt'', and are replaced by aligned material growing from the disordered melt [22][23][24][25]. This acts as an effective mechanism for mesophase alignment.…”

Block copolymer–nanoparticle composites: Structure, functional properties, and processing

“…Successful use of electric field for alignment of neat BCPs and BCP-NP composites requires sufficient dielectric contrast between two adjacent polymeric domains [328]. Incorporation of NPs can enhance the dielectric contrast and thus can enable electric field-induced alignment and orientation of various ordered BCP-NP composite structures such as lamellar and cylinders [328].…”

Tuned, driven, and active soft matter

“…Due to the reorientation effects, it can serve to heal multi-domain textures and obtain a monodomain structure [210,221,223,238,251,253]. Apart from shear, alignments can also be induced by other routes, for example by applying external electrical fields to materials that show a dielectric contrast between their blocks [229,[254][255][256][257][258][259][260][261][262][263][264][265][266][267]. From a technological point of view, block copolymers possess a high potential for applications in the nano-sciences [268][269][270]: they provide regular periodic arrays of tunable material properties on the molecular length scales of the different blocks.…”