Epitaxial Transition from Gyroid to Cylinder in a Diblock Copolymer Melt

Honda, Toshio; Kawakatsu, Toshihiro

doi:10.1021/ma052075z

Cited by 70 publications

(103 citation statements)

References 55 publications

(177 reference statements)

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“…It will be possible to use the experimentally determined χ parameters by employing more accurate free energy model such as the SCF model [15,16,27] and efficient numerical algorithms. (We note that recently Honda and Kawakatsu [66] proposed the hybrid theory of the DF and the SCF and reported that accurate and numerically efficient simulations can be performed by the hybrid method. By employing their method, accurate and fast simulations for the dynamics of micelles and vesicles may be possible.)…”

Section: Resultsmentioning

confidence: 95%

Density functional simulation of spontaneous formation of vesicle in block copolymer solutions

Uneyama

2007

The Journal of Chemical Physics

112

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We carry out numerical simulations of vesicle formation based on the density functional theory for block copolymer solutions. It is shown by solving the time evolution equations for concentrations that a polymer vesicle is spontaneously formed from the homogeneous state. The vesicle formation mechanism obtained by our simulation agree with the results of other simulations based on the particle models as well as experiments. By changing parameters such as the volume fraction of polymers or the Flory-Huggins interaction parameter between the hydrophobic subchains and solvents, we can obtain the spherical micelles, cylindrical micelles or bilayer structures, too. We also show that the morphological transition dynamics of the micellar structures can be reproduced by controlling the Flory-Huggins interaction parameter.

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Section: Resultsmentioning

confidence: 95%

Density functional simulation of spontaneous formation of vesicle in block copolymer solutions

Uneyama

2007

The Journal of Chemical Physics

112

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“…Initial theoretical calculations by Matsen in 1998 suggested a low-energy pathway for the GYR → CYL transition, [ [ 85 ] which was supported by simulations, and experimentally observed by Schmidt et al in 2010 [86][87][88] (Figure 4 b). Figure 4 a shows calculated structures for the transition from CYL → GYR and vice versa.…”

Section: Gyroid To Cylindermentioning

confidence: 59%

Beyond Orientation: The Impact of Electric Fields on Block Copolymers

Liedel

Pester

Ruppel

et al. 2011

Macro Chemistry & Physics

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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.

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“…An efficient numerical strategy, relying on this approximation, is the SCFT method. [37][38][39] In the following, we briefly review the SCFT method for a melt composed of AB-diblock copolymers, 39 for which, due to screening effects between the monomers, we can assume Gaussian statistics for the chain conformation. Within this approximation, each polymer chain consists of N A segments of A-type and N B segments of B-type with their respective statistical segment lengths b A and b B , which means that the total number of statistical segments of a chain is N = N A + N B .…”

Section: Methods and Simulation Detailsmentioning

confidence: 99%

A multiscale modeling study of loss processes in block-copolymer-based solar cell nanodevices

Donets

Pershin

Christlmaier

et al. 2013

The Journal of Chemical Physics

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Articles you may be interested inOptimizing the fabrication process and interplay of device components of polymer solar cells using a field-based multiscale solar-cell algorithm J. Chem. Phys. 142, 184902 (2015) Flexible photovoltaic devices possess promising perspectives in opto-electronic technologies, where high mobility and/or large-scale applicability are important. However, their usefulness in such applications is currently still limited due to the low level of optimization of their performance and durability. For the improvement of these properties, a better understanding and control of small-scale annihilation phenomena involved in the photovoltaic process, such as exciton loss and charge carrier loss, is necessary, which typically implicates multiple length-and time-scales. Here, we study the causes for their occurrence on the example of nanostructured diblock-and triblock-copolymer systems by making use of a novel solar-cell simulation algorithm and explore new routes to optimize their photovoltaic properties. A particular focus is set on the investigation of exciton and charge carrier loss phenomena and their dependence on the inter-monomeric interaction strength, chain architecture, and external mechanical loading. Our simulation results reveal that in the regime from low up to intermediate χ -parameters an increasing number of continuous percolation paths is created. In this parameter range, the internal quantum efficiency (IQE) increases up to a maximum, characterized by a minimum in the number of charge losses due to charge recombination. In the regime of high χ -parameters both block-copolymer systems form nanostructures with a large number of bottlenecks and dead ends. These lead to a large number of charge losses due to charge recombination, charge trapping, and a deteriorated exciton dissociation, resulting in a significant drop in the IQE. Moreover, we find that the photovoltaic performance of the triblock-copolymer material decreases with increasing mechanical loading, caused by a growing number of charge losses due to charge recombination and charge accumulation. Finally, we demonstrate that the process of charge trapping in defects can be reversed by changing the polarity of the electrodes, which confers these materials the ability to be used as charge storage media.

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Epitaxial Transition from Gyroid to Cylinder in a Diblock Copolymer Melt

Cited by 70 publications

References 55 publications

Density functional simulation of spontaneous formation of vesicle in block copolymer solutions

Density functional simulation of spontaneous formation of vesicle in block copolymer solutions

Beyond Orientation: The Impact of Electric Fields on Block Copolymers

A multiscale modeling study of loss processes in block-copolymer-based solar cell nanodevices

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