Self‐Assembly of Cylinder‐Forming ABA Triblock Copolymers under Cylindrical Confinement

Wang, Zheng; Li, Baohui; Jin, Qinhan; Ding, Datong; Shi, An‐Chang

doi:10.1002/mats.200800010

Cited by 32 publications

(13 citation statements)

References 51 publications

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“…It is suggested that initial microwave treatment results in the formation of regular patterns since as spun films showed no long-range order. At longer time periods, the film appears to move through an order-disorder transition and becomes significantly less well-ordered [24,25]. This may be explained by increased solvent swelling as the exposure to solvent during irradiation is increased.…”

Section: Effect Of Anneal Time On Self-assemblymentioning

confidence: 99%

Block Co-Polymers for Nanolithography: Rapid Microwave Annealing for Pattern Formation on Substrates

et al. 2015

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The integration of block copolymer (BCP) self-assembled nanopattern formation as an alternative lithographic tool for nanoelectronic device fabrication faces a number of challenges such as defect densities, feature size, pattern transfer, etc. Key barriers are the nanopattern process times and pattern formation on current substrate stack layers such as hard masks (e.g., silicon nitride, Si3N4). We report a rapid microwave assisted solvothermal (in toluene environments) self-assembly and directed self-assembly of a polystyrene-blockpolydimethylsiloxane (PS-b-PDMS) BCP thin films on planar and topographically patterned Si3N4 substrates. Hexagonally arranged, cylindrical structures were obtained and good pattern ordering was achieved. Factors affecting BCP self-assembly, notably anneal time and temperature, were studied and seen to have significant effects. Graphoepitaxy within the topographical structures provided long range, translational alignment of the patterns. The effect of surface topography feature size and spacing was investigated. The solvothermal microwave based technique used to provide periodic order in the BCP patterns showed significant promise and ordering was achieved in much shorter periods than more conventional thermal and solvent annealing methods. The implications of the work in terms of manufacturing technologies are discussed. OPEN ACCESSPolymers 2015, 7 593

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Section: Effect Of Anneal Time On Self-assemblymentioning

confidence: 99%

Block Co-Polymers for Nanolithography: Rapid Microwave Annealing for Pattern Formation on Substrates

et al. 2015

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“…Imposing a geometric confinement on block copolymers has been widely recognized as an alternative to creating novel ordered nanostructures, compared to the other means that involve the variation of chemical compositions, architectures, and interactions between immiscible blocks in block copolymers. − Many efforts in this area have been devoted to exploiting self-assembled yet constrained nanostructures. , In this context, self-assembly of block copolymers, such as linear AB diblock , and ABC star in different confined geometries , including thin-film and cylindrical and hexagonal nanopores, has been intensively investigated theoretically ,, using self-consistent mean-field theory (SCMFT), Monte Carlo simulation, ,,,− and dissipative particle dynamics calculation, etc. Notably, self-consistent field theory has been extensively employed to explore the formation of nanostructures under confinement as the corresponding free energy can be readily calculated.…”

Section: Introductionmentioning

confidence: 99%

Rich Variety of Three-Dimensional Nanostructures Enabled by Geometrically Constraining Star-like Block Copolymers

Wang

et al. 2016

Langmuir

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The influence of star-like architecture on phase behavior of star-like block copolymer under cylindrical confinement differs largely from the bulk (i.e., nonconfinement). A set of intriguing self-assembled morphologies and the corresponding phase diagrams of star-like (AB)f diblock copolymers with different numbers of arms f (i.e., f = 3, 9, 15, and 21) in four scenarios (ϕA = 0.3 and V0 > 0; ϕA = 0.3 and V0 < 0; ϕA = 0.7 and V0 > 0; and ϕA = 0.7 and V0 < 0 (where ϕA is the volume fraction of A block) and V0 < 0 and V0 > 0 represent that the pore wall of cylindrical confinement prefers the inner A block (i.e., A-preferential) and B block (i.e., B-preferential), respectively) were for the first time scrutinized by employing the pseudospectral method of self-consistent mean-field theory. Surprisingly, a new nanoscopic phase, that is, perforated-lamellae-on-cylinder (denoted PC), was observed in star-like (AB)3 diblock copolymer at ϕA = 0.3 and V0 > 0. With a further increase in f, a single lamellae (denoted L1) was found to possess a larger phase region. Under the confinement of A-preferential wall (i.e., V0 < 0) at ϕA = 0.3, PC phase became metastable and its free energy increased as f increased. Quite intriguingly, when ϕA = 0.7 and V0 > 0, where an inverted cylinder was formed in bulk, the PC phase became stable, and its free energy decreased as f increased, suggesting the propensity to form PC phase under this condition. Moreover, in stark contrast to the phase transition of C1 → L1 → PC (C1, a single cylindrical microdmain) at ϕA = 0.3 and V0 > 0, when subjected to the A-preferential wall (ϕA = 0.7), a different phase transition sequence (i.e., C1 → PC → L1) was identified due to the formation of a double-layer structure. On the basis of our calculations, the influence of star-like architecture on (AB)f diblock copolymer under the imposed cylindrical confinement, particularly the shift of the phase boundaries as a function of f, was thoroughly understood. These self-assembled nanostructures may hold the promise for applications as lithographic templates for nanowires, photonic crystals, and nanotechnology.

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“…Consequently, a rich variety of novel structures, such as complex helices and other curved structures, have been predicted in these MC simulations. [29][30][31][32][33] These studies focus on the effects of pore diameters and preferential surfaces on the confinementinduced morphologies where a copolymer topology of three sequentially arranged blocks is usually taken into account. ABC star triblock copolymers can be self-assembled into interesting structures in the pore geometries, although few experiments and simulations have been reported.…”

Section: Introductionmentioning

confidence: 99%

Nanostructures and phase diagrams of ABC star triblock copolymers in pore geometries

Qiu

Zhang

et al. 2012

The Journal of Chemical Physics

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The nanostructures and phase diagrams of ABC star triblock copolymers in pore geometries are investigated using the real-space self-consistent field theory in two-dimensional space. Two types of pores with neutral surfaces, namely, pores with small and large diameters, are considered. A rich variety of nanostructures are exhibited by the ABC star triblock copolymers in these two types of pores, which differ from those observed in bulk and in other confinements. These structures include perpendicular undulating lamellae, concentric core-shell cylinders, polygonal tiling with cylindrical arrangements, and other complex structures. Triangular phase diagrams for the ABC star triblock copolymers are constructed. The small pores clearly affect the corner and central space of the phase diagrams by distorting the bulk structures into concentric arrangements. Meanwhile, the large pores induce the transformation of bulk structures into concentric structures in most of the phase space, but slightly affect the structures at the center of the phase diagrams. Furthermore, the order-order and order-disorder phase transitions, as well as the stable and metastable phases, in the triangular phase diagrams are examined by analyzing their free energies. These observations on the ABC star triblock copolymers in the pore geometries provide a deeper insight into the behavior of macromolecules in a confined system.

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Self‐Assembly of Cylinder‐Forming ABA Triblock Copolymers under Cylindrical Confinement

Cited by 32 publications

References 51 publications

Block Co-Polymers for Nanolithography: Rapid Microwave Annealing for Pattern Formation on Substrates

Block Co-Polymers for Nanolithography: Rapid Microwave Annealing for Pattern Formation on Substrates

Rich Variety of Three-Dimensional Nanostructures Enabled by Geometrically Constraining Star-like Block Copolymers

Nanostructures and phase diagrams of ABC star triblock copolymers in pore geometries

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