Self-assembly of rod–coil block copolymers

Olsen, Bradley D.; Segalman, Rachel A.

doi:10.1016/j.mser.2008.04.001

Cited by 345 publications

(355 citation statements)

References 231 publications

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“…The morphologies of these systems are susceptible to kinetic trapping, and thin film morphologies therefore also quite often depend on film deposition and processing conditions, leading to a variety of interesting structures, which are described in a thorough review on rod-coil diblock copolymers. 95 Recently however, Olsen et al have been able to study the equilibrium self assembly of weakly segregated lamellar poly-2,5-di(2 0 -ethylhexyloxy)-1,4-phenylenevinyleneblock-polyisoprene (DEH-PPV-b-PI). Comparable to coil-coil diblock copolymers, these systems also form holes and islands of parallelly oriented microdomains, due to preferential wetting of the substrate with PI.…”

Section: Functional Block Copolymersmentioning

confidence: 99%

Thin films of complexed block copolymers

2009

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Due to their ability to microphase separate into well ordered structures with periodicities on the nanometre scale, block copolymers have received widespread attention as building blocks for the fabrication of nanomaterials. In particular, thin films of block copolymers promise new technological breakthroughs in e.g. computer memory applications. This Review gives a short overview of progress that has been made in preparing suitable thin films of conventional coil-coil diblock copolymer systems, while the advantages as well as the complexities of using more unconventional systems such as triblock copolymers and supramolecular systems are emphasized. Gerrit tenBrinke obtained his PhD in Statistical Physics from the University of Groningen, The Netherlands. He spent two years as a postdoctoral fellow at the University of Massachusetts at Amherst. In 1985 he became Associate Professor in the Polymer Department of the University of Groningen and in 1996 Professor. During 1994-1999 he was also part time Professor at the Helsinki University of Technology working closely together with Olli Ikkala. His research interests are self-assembly in complex polymer systems.

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Section: Functional Block Copolymersmentioning

confidence: 99%

Thin films of complexed block copolymers

2009

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“…When different (in size, shape or interaction potential) molecular fragments are combined into a single molecule, then one obtains the so-called polyphilic material [1,2] (the simplest example being well-known amphiphiles). If such a molecule is big enough, then it represents a supermolecular object, although the supramolecular effects are also possible via self-assembly of polyphilic macromolecules into bulk ordered phases [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Relation between the grafting density of liquid crystal macromolecule and the symmetry of self-assembled bulk phase: coarse-grained molecular dynamics study

Ilnytskyi¹

2013

Condens. Matter Phys.

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I consider a generic coarse-grained model suitable for the study of bulk self-assembly of liquid crystal (LC) macromolecules. The cases include LC dendrimers, gold nanoparticles modified by polymer chains with terminating LC groups and others. The study is focused on the relation between a number of grafted chains, AE , and the symmetry of the self-assembled bulk phases. Simple space-filling arguments are used first to estimate stability intervals for a rod-like, disc-like and spherulitic conformations in terms of AE . These are followed by coarse-grained molecular dynamics simulations for both spontaneous and aided self-assembly of LC macromolecules into bulk phases. In spontaneous self-assembly runs, essential coexistence of rod-like and disc-like conformations is observed (via analysis of the histograms for the molecular asphericity) in a broad interval of AE , which prevents the formation of defect-free structures. The use of uniaxial and planar aiding fields is found to improve self-assembly into monodomain phases by promoting conformations of respective symmetry. Strong shape-phase relation, observed experimentally, is also indicated by the simulations by the coincidence of the stability intervals for the respective conformations with those for the bulk phases.

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“…It has proved possible to engineer molecules to contain aliphatic, aromatic, hydrogen bonding and fluorinated segments, all of which can be combined together (in different ways) to produce differing molecular architectures. In one sense the simplest polyphilic mesogens are linear or star-shaped ABC triblock copolymers, which undergo microphase separation to produce interesting mesophase structures [1][2][3][4].However, the range of molecular architectures possible are limited only by the ingenuity of chemists. Recent interesting examples include the use of calamitic bolaamphiphiles with a rigid rod-like aromatic unit, two hydrophilic terminal groups, and a liphophilic or semifluorinated lateral alkyl chain [5][6][7]; and the use of 'Janus molecules' with two groups of differing mesogens tethered to a molecular core via semi-flexible spacers [8].…”

Section: Introductionmentioning

confidence: 99%

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

Ilnytskyi¹,

Lintuvuori²,

Wilson³

2010

Condens. Matter Phys.

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A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr) is presented. It allows, for the first time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008)]. Coarse-grained (CG) molecular dynamics (MD) simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning field of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like), leading to formation of a monodomain smectic A (Sm A ) or a columnar (Col) phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.

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Self-assembly of rod–coil block copolymers

Cited by 345 publications

References 231 publications

Thin films of complexed block copolymers

Thin films of complexed block copolymers

Relation between the grafting density of liquid crystal macromolecule and the symmetry of self-assembled bulk phase: coarse-grained molecular dynamics study

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

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