Structure of minimum thickness and terraced free-standing films of block copolymers

Radzilowski, L. H.; Carvalho, Bruce L.; Thomas, Edwin L.

doi:10.1002/(sici)1099-0488(199612)34:17<3081::aid-polb20>3.0.co;2-2

Cited by 108 publications

(153 citation statements)

References 0 publications

Supporting

Mentioning

132

Contrasting

Order By: Relevance

“…28, 31͒ and other noncylindrical morphologies, have been observed too. 23,24,28 The presence of noncylindrical morphologies is an interesting feature of films of asymmetric copolymers. These observations support a weak segregation limit ͑WSL͒ analysis, which has predicted that homogeneous surface fields can drive a transition from a cylindrical to a lamellar phase.…”

Section: A Block Copolymer Thin Filmssupporting

confidence: 91%

“…28 Two different phases were observed; a CL ʈ structure in the thinnest part of the film and a C ʈ phases in the rest of the film. These two phases are predicted with the DDFT calculations.…”

Section: Phase Behavior In a Slitmentioning

confidence: 92%

“…It is hard to sketch a complete picture of the film behavior with the help of the experimental data [22][23][24][25][26][27][28][29][30][31] and theoretical investigations, 32,33 published in the literature. Our research will focus on block copolymers, that form cylindrical domains in the bulk melt.…”

Section: A Block Copolymer Thin Filmsmentioning

confidence: 99%

“…In the PS-PB films a spherical or C Ќ phase has been observed too. 28 This phase exist at film thicknesses between the L ʈ and the C ʈ phases, which agrees with our calculations.…”

Section: Phase Behavior In a Slitmentioning

confidence: 99%

See 3 more Smart Citations

Asymmetric block copolymers confined in a thin film

Huinink

Brokken-Zijp

Dijk

et al. 2000

The Journal of Chemical Physics

186

318

View full text Add to dashboard Cite

We have used a dynamic density functional theory ͑DDFT͒ for polymeric systems, to simulate the formation of micro phases in a melt of an asymmetric block copolymer, A n B m ( f A ϭ1/3), both in the bulk and in a thin film. In the DDFT model a polymer is represented as a chain of springs and beads. A spring mimics the stretching behavior of a chain fragment and the spring constant is calculated with the Gaussian chain approximation. Simulations were always started from a homogeneous system. We have mainly investigated the final morphology, adopted by the system. First, we have studied the bulk behavior. The diblock copolymer forms a hexagonal packed array of A-rich cylinders, embedded in a B-rich matrix. Film calculations have been done by confining a polymer melt in a slit. Both the slit width and surface-polymer interactions were varied. With the outcomes a phase diagram for confined films has been constructed. Various phases are predicted: parallel cylinders (C ʈ ), perpendicular cylinders (C Ќ ), parallel lamellae (L ʈ ), and parallel perforated lamellae (CL ʈ ). When the film surfaces are preferentially wet by either the A or the B block, parallel oriented microdomains are preferred. A perpendicular cylindrical phase is stable when neither the A nor B block preferentially wets the surfaces. The predicted phase diagram is in accordance with experimental data in the literature and explains the experimentally observed differences between films of asymmetric block copolymers with only two parameters: the film thickness and the energetic preference of the surface for one of the polymer blocks. We have also observed, that confinement speeds up the process of long range ordering of the microdomains.

show abstract

Section: A Block Copolymer Thin Filmssupporting

confidence: 91%

Section: Phase Behavior In a Slitmentioning

confidence: 92%

Section: A Block Copolymer Thin Filmsmentioning

confidence: 99%

“…In the PS-PB films a spherical or C Ќ phase has been observed too. 28 This phase exist at film thicknesses between the L ʈ and the C ʈ phases, which agrees with our calculations.…”

Section: Phase Behavior In a Slitmentioning

confidence: 99%

See 2 more Smart Citations

Asymmetric block copolymers confined in a thin film

Huinink

Brokken-Zijp

Dijk

et al. 2000

The Journal of Chemical Physics

186

318

View full text Add to dashboard Cite

show abstract

“…[24]. The present real-time, in situ GISAXS investigations elucidate the time scales of the inner structural changes within the entire film thickness, in contrast to methods like transmission electron microscopy (TEM), which are used to inspect the internal structure of polymer thin films, are limited to stable structures [25]. Neither is ex situ, post-treatment AFM not sufficient to reveal these processes since it only monitors the surface texture.…”

Section: Discussionmentioning

confidence: 99%

Creation of lateral structures in diblock copolymer thin films during vapor uptake and subsequent drying – Effect of film thickness

Sepe

Černoch

Štěpánek

et al. 2014

European Polymer Journal

View full text Add to dashboard Cite

a b s t r a c tWe have studied the structure formation in compositionally nearly symmetric poly(4-octylstyrene-b-butylmethacrylate) diblock copolymer films during exposure to saturated vapor of n-hexane (a poor solvent for both blocks) and subsequent drying using real-time, in situ grazing-incidence small-angle X-ray scattering (GISAXS). Previous bulk studies revealed a lamellar structure after thermo-annealing; and surface studies on hexane treated samples revealed a lateral surface structure (Č ernoch et al., 2007) [14]. We focus here on the effect of film thickness which is varied between 1.3 and 2.0 times the bulk lamellar thickness. We report on the lateral repeat distance as well as on the correlation length in the film plane. Complex, non-monotonous behavior is observed for both parameters. Upon drying, the lateral structure created during vapor treatment is stable only for the thick film, not for the intermediate and the thin film. The kinetics depends strongly on the film thickness; especially for the thinnest film, it is very slow. For all film thicknesses, we attempt to identify the most stable morphology, occurring when the inner film structure is close to the one in the bulk.

show abstract

Macromolecular Engineering via Carbocationic Polymerization: Branched Structures, Block Copolymers and Nanostructures

Puskás¹,

Antony

Kwon

et al. 2001

Macromol. Mater. Eng.

View full text Add to dashboard Cite

This article features macromolecular engineering via carbocationic polymerization, the focus of research of the recently established Macromolecular Engineering Research Centre (MERC) at the University of Western Ontario. The fundamental philosophy of MERC is interdisciplinary research with a strong industrial orientation, while emphasizing the quest for fundamental understanding of polymerization processes and polymer structure‐property relationships. First, a brief overview of living polymerizations in general, and living carbocationic polymerizations in particular will be given. This latter technique is of interest because some monomers (e. g., isobutylene) can be polymerized by cationic techniques only, to yield polymers with unique properties (e. g., polyisobutylene with superior chemical and oxidative stability, low permeability and high damping). This will be followed by an overview of our research strategy and a summary of our latest results. These include the development of a fiber‐optic mid‐FTIR method for the real‐time monitoring of low temperature polymerization processes, the discovery that selected epoxides initiate effectively the living carbocationic polymerization of isobutylene, fundamental studies into the mechanism and kinetics of living carbocationic polymerization, and the design and synthesis of various polymer architectures (e. g., branched homo‐ and block copolymers) with improved properties and nanostructured phase morphologies.

show abstract

Structure of minimum thickness and terraced free-standing films of block copolymers

Cited by 108 publications

References 0 publications

Asymmetric block copolymers confined in a thin film

Asymmetric block copolymers confined in a thin film

Creation of lateral structures in diblock copolymer thin films during vapor uptake and subsequent drying – Effect of film thickness

Macromolecular Engineering via Carbocationic Polymerization: Branched Structures, Block Copolymers and Nanostructures

Contact Info

Product

Resources

About