Observed Surface Energy Effects in Confined Diblock Copolymers

Kellogg, G. J.; Walton, D. G.; Mayes, Anne M.; Lambooy, P.; Russell, Thomas P.; Gallagher, Patrick; Satija, Sushil K.

doi:10.1103/physrevlett.76.2503

Cited by 328 publications

(353 citation statements)

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“…In principle, it must be possible to do experiments on films with nonselective surfaces by coating the film substrate with a thin layer of a random copolymer, because this has already been done with films of symmetric block copolymers. 14,15 Second, we have predicted various C Ќ phases at certain values of H in slits with selective surfaces, but most of these phases are not observed in the experiments discussed above. We are convinced that this is a consequence of the difference between confined and unconfined films.…”

Section: Phase Behavior In a Slitmentioning

confidence: 99%

“…Direct evidence for these phases can only be obtained by experiments on confined films, which has already been done with symmetric diblock copolymers. 14 …”

Section: Phase Behavior In a Slitmentioning

confidence: 99%

“…13,16 Random copolymers have been used to tune the interactions between the interfaces and the two different copolymer blocks. 14,15 Films with nonselective surfaces have been prepared in this way. In these films, confined and unconfined, the frustration of the lamellar period is avoided by changing the orientation of the lamellae from parallel with to perpendicular to the film surfaces.…”

Section: A Block Copolymer Thin Filmsmentioning

confidence: 99%

“…Thin films have been studied extensively by experiments [5][6][7][8][9][10][11][12][13][14][15] and theory. [16][17][18][19][20][21] In these films the microdomains have a lamellar shape as in a bulk system.…”

Section: A Block Copolymer Thin Filmsmentioning

confidence: 99%

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Asymmetric block copolymers confined in a thin film

Huinink

Brokken-Zijp

Dijk

et al. 2000

The Journal of Chemical Physics

186

318

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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.

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Section: Phase Behavior In a Slitmentioning

confidence: 99%

“…Direct evidence for these phases can only be obtained by experiments on confined films, which has already been done with symmetric diblock copolymers. 14 …”

Section: Phase Behavior In a Slitmentioning

confidence: 99%

Section: A Block Copolymer Thin Filmsmentioning

confidence: 99%

Section: A Block Copolymer Thin Filmsmentioning

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

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“…By analogy with surface chemistry strategies used to orient block copolymer films [104][105][106][107][108][109], the Rankin group has reported the synthesis of mp-TiO 2 thin films with orthogonally tilted HCP (o-HCP) cylindrical nanopores using EISA with P123 as structure directing agent and titanium(IV) ethoxide as titania precursor [83,110]. The hypothesis underlying this approach is that orthogonal alignment of the HCP mesophase can be achieved in EISA-derived ceramic film by modifying the substrate surface so that it interacts equally with both blocks of the P123 template, making it chemically "neutral" towards the template surfactant.…”

Section: Surfactant-templated Film Depositionmentioning

confidence: 99%

Synthesis and Catalytic Applications of Non-Metal Doped Mesoporous Titania

et al. 2017

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Mesoporous titania (mp-TiO 2 ) has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO 2 . However, because the large band gap of TiO 2 limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO 2 . While first-principles calculations support the efficacy of this approach, it is challenging to efficiently introduce active non-metal dopants into the lattice of TiO 2 . This review surveys recent advances in the preparation of mp-TiO 2 and their doping with non-metal atoms. Different doping strategies and dopant sources are discussed. Further, co-doping with combinations of non-metal dopants are discussed as strategies to reduce the band gap, improve photogenerated charge separation, and enhance visible light absorption. The improvements resulting from each doping strategy are discussed in light of potential changes in mesoporous architecture, dopant composition and chemical state, extent of band gap reduction, and improvement in photocatalytic activities. Finally, potential applications of non-metal-doped mp-TiO 2 are explored in water splitting, CO 2 reduction, and environmental remediation with visible light.

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Block copolymer films on patterned surfaces

Chen¹

1998

J. Polym. Sci. B Polym. Phys.

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We present results from a numerical study of a coarse‐grained model of diblock copolymer (BCP) thin films cast on a chemically patterned surface. The patterned surface contains chemical inhomogeneities with a repeat spacing length scale comparable to the linear size of the BCP molecules. We find that the orientation of the lamellae in the thin film and the overlap of the film morphology with the preassigned surface pattern is strongly influenced by the commensurability between the bulk unconstrained lamellar size λ*, and the linear size of the surface inhomogeneities w. PACS Numbers: 64.60.Cn, 61.41.+e, 64.60.My, 64.75.+g. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 3127–3136, 1998

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Observed Surface Energy Effects in Confined Diblock Copolymers

Cited by 328 publications

References 13 publications

Asymmetric block copolymers confined in a thin film

Asymmetric block copolymers confined in a thin film

Synthesis and Catalytic Applications of Non-Metal Doped Mesoporous Titania

Block copolymer films on patterned surfaces

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