Self-assembly of block copolymer thin films

Albert, Julie N. L.; Epps, Thomas H.

doi:10.1016/s1369-7021(10)70106-1

Cited by 472 publications

(539 citation statements)

References 104 publications

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“…However, to consistently gain this sort of structure, considerable control over the polymer orientation is required, something which is not always facile and is particularly susceptible to changes in substrates and solvents. 119 It was also noted elsewhere, as an intuitive argument, that placing insulating groups right next to the electrodes would considerably diminish charge transfer and that rather, a parallel placement of block copolymers with respect the electrodes might be more appropriate. 169 This would also enhance the particularly important polymer-electrode interactions.…”

Section: As Single and Multicomponent Layersmentioning

confidence: 96%

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Block copolymer strategies for solar cell technology

Topham¹,

Parnell²,

Hiorns³

2011

J Polym Sci B Polym Phys

186

169

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A simple overview of the methods used and the expected benefits of block copolymers in organic photovoltaic devices is given in this review. The description of the photovoltaic process makes it clear how the detailed self-assembly properties of block copolymers can be exploited. Organic photovoltaic technology, an inexpensive, clean and renewable energy source, is an extremely promising option for replacing fossil fuels. It is expected to deliver printable devices processed on flexible substrates using high-volume techniques. Such devices, however, currently lack the long-term stability and efficiency to allow organic photovoltaics to surpass current technologies. Block copolymers are envisaged to help overcome these obstacles because of their long term structural stability and their solid-state morphology being of the appropriate dimensions to efficiently perform charge collection and transfer to electrodes.

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Section: As Single and Multicomponent Layersmentioning

confidence: 96%

“…For a more comprehensive overview of block copolymer self-assembly in thin films, the reader is directed elsewhere. 119 …”

Section: Conjugated Rod-based Block Copolymersmentioning

confidence: 99%

Block copolymer strategies for solar cell technology

Topham¹,

Parnell²,

Hiorns³

2011

J Polym Sci B Polym Phys

186

169

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“…As it has been shown in this study, on SiO 2 at pH 4, there was a thin sophorolipids layer, and the SEM images show a network similar to the one observed in the surface assembly of block copolymers. 20,103 By definition, the spinodal decomposition was a clustering phase change from a homogeneous matter that separated spontaneously into two phases due to a small fluctuation of density or composition. 104 Two other phenomena could explain the phase separation within a film.…”

Section: Q8mentioning

confidence: 99%

“…Block copolymers have been intensively explored as they are known to assemble spontaneously on planar surfaces or when constrained as thin films. [17][18][19][20] Modification of hydrophobic/hydrophilic block ratio, 21 or the chemical nature of one block, 22 are well-known methods to change the wettability of a surface and influence the surface pattern. Even though these approaches are well-established, drawbacks exist in terms of tedious process involved in controlling homogeneity 23 and the necessity of solvent and temperature annealing.…”

Section: Introductionmentioning

confidence: 99%

Surface-induced assembly of sophorolipids

Peyre

Hamraoui

Faustini

et al. 2017

Phys. Chem. Chem. Phys.

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The surface self-assembly properties of acidic sophorolipids, a bolaform microbial glycolipids with pHresponsive properties in solution, were studied based on the chemical nature of the support and pH of the solution. Sophorolipids generally form micelles in water but formation of morphologies like platelets and twisted fibers depending on pH have also been reported. The surface self-assembly was achieved using dip-coating on three different substrates namely gold, silicon(111) and TiO 2 anatase. Deposition conditions (dip-coating withdrawal speed, relative humidity, temperature) were tested, and it was found that optimum self-assembly occurred at a withdrawal speed of 1 mm s À1 , T of 25 1C and relative humidity of 25%. The local structure of the sophorolipid films was characterized by Atomic Force Microscopy, while Scanning Electron Microscopy was used to characterize the spatial homogeneity. We also attempted to correlate dispersive, electron donor and electron attractor surface energy components, using Good-Van Oss's approach, and the behavior of sophorolipids. We found that when the surface energy is dominated by dispersive components, sophorolipids spontaneously assemble into entangled needles at all pH values (4, 6 and 11). However, when the surface energy is dominated by electronic components, pH has a strong influence on the surface self-assembly. We could discriminate three major organizations: homogeneous layer, isolated aggregates and a two-dimensional network similar to block copolymer surface self-assembly.

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“…Otherwise, the polymer chain assembly relies on the chemical and electronic interactions between a monolayer and a substrate [13], or a combination of inter-and intramolecular interactions, which might be influenced by effects such as molecular recognition, charge separation, electron transfer and/or hydrophilic and hydrophobic forces within or between adjacent polymer chains [14]. Traditionally, patterned polymer films are obtained by the controlled phase separation on surfaces with regions of different surface tension [15,16], or by the arrangement of sequences in block copolymers [17]. The formation of surface patterns from spin-cast films is caused by a solvent quench, in which the solvent is removed rapidly from the polymer solution and induces phase separation of the two dissolved polymers.…”

Section: Introductionmentioning

confidence: 99%

Morphologies and Thermal Variability of Patterned Polymer Films with Poly(styrene-co-maleic anhydride)

Samyn

Schoukens

2014

Polymers

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Patterned films of poly(styrene-co-maleic anhydride) copolymers were deposited by dip-coating from acetone solutions. A qualitative study of the film morphologies shows the formation of polymer spheres with smaller diameters at higher amounts of maleic anhydride (MA), and long-fibrous features at higher molecular weights. Upon heating, the films progressively re-assemble with short-and long-fibrous structures as a function of heating time and temperature. In parallel, the film morphologies are quantified by image processing and filtering techniques. The differential scanning calorimetry confirms the higher glass transition temperatures with increasing amount of MA. The analysis with Raman spectroscopy shows interactions between the molecules in solution and effects of ring-opening (hydrolysis) and ring-closure (formation of MA) during drying of the films. The water contact angles on the patterned films are within the hydrophilic range. They mainly correlate with the amount of MA moieties calculated from spectroscopy, while the roughness parameters have a minor effect. The variations in film patterns illustrate the self-assemble ability of the copolymers and confirm a heterogeneous molecular structure, as previously assumed.

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Self-assembly of block copolymer thin films

Cited by 472 publications

References 104 publications

Block copolymer strategies for solar cell technology

Block copolymer strategies for solar cell technology

Surface-induced assembly of sophorolipids

Morphologies and Thermal Variability of Patterned Polymer Films with Poly(styrene-co-maleic anhydride)

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