Understanding nanodomain morphology formation in dip-coated PS-<i>b</i>-PEO thin films

Nguyen, Hoang M.; Mader, Ariane V.; De, Swarnalok; Vapaavuori, Jaana

doi:10.1039/d1na00263e

Cited by 5 publications

(6 citation statements)

References 80 publications

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“…First of all, it is clear that the two plain BCPs exhibit different surface morphologies. For PS-b-PEO, the surface shows a uniform dot pattern (dots resulting from the organization of cylindrical domains of PEO; similar to the one reported for PS-b-PEO fabricated with a dip-coating technique [51] ), while for PEO-b-PS a featureless surface without any specific pattern is seen.…”

Section: Depositions On Bcpssupporting

confidence: 73%

“…The fact that BCP thin films can be tailored to exhibit various self‐assembly schemes in nanometer length scales resulting in unique surface patterns motivated us to challenge them in this study. Moreover, these surface patterns/characteristics can be easily controlled by varying fabrication parameters, such as withdrawal speed of dip coating and solvent of spin coating, [ 1,51 ] and also by the choice of the individual polymer components of BCPs, depending on the different application requirements. For the present study, our systematic experiments on the homopolymers gave us important design guidelines for the choice of the polymer components in our BCP substrates.…”

Section: Resultsmentioning

confidence: 99%

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Block Copolymer Approach toward Selective Atomic‐Layer Deposition of ZnO Films

Philip,

Dong,

Vapaavuori

et al. 2023

Adv Eng Mater

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High‐quality thin films of ZnO fabricated with atomic layer precision are attracting increasing interest in various applications beyond the conventional semiconductor industry. This has posed new demands for these thin films regarding for example the substrate compatibility and substrate‐selective deposition. Here we investigate the impact of different underlining polymer substrates on the film growth characteristics of ZnO coatings fabricated with the atomic layer deposition (ALD) technique. The resultant thin films are systematically characterized for the growth rate, crystallinity, surface morphology, hydrophilicity and electrical conductivity. Most excitingly, based on the understanding gained for the ZnO film growth on the different homopolymer surfaces, we designed and fabricated nanoscale‐patterned block copolymer (BCP) films via spin coating to demonstrate block‐selective ALD of ZnO on these BCP surfaces. We will show that the polyethylene oxide (PEO) parts of the BCP act as a significantly more passive surface for the ZnO growth than the polystyrene (PS). Altogether, this concept couples two highly controllable methods – atomic‐level precision of ALD and nanoscale precision of BCP substrates ‐ into a simple and scalable way of producing diverse nanomaterial patterns.This article is protected by copyright. All rights reserved.

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Section: Depositions On Bcpssupporting

confidence: 73%

Section: Resultsmentioning

confidence: 99%

Block Copolymer Approach toward Selective Atomic‐Layer Deposition of ZnO Films

Philip,

Dong,

Vapaavuori

et al. 2023

Adv Eng Mater

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“…Figure d shows the illustration of the AFM-IR measurements, which consist of four main components: pulsed tunable IR sources, deflection laser, photodiode, and cantilever Figure e shows the AFM phase image of a PS- b -PEO/4AzOH film, where the brighter and darker regions are the PS and PEO domains, respectively . From the IR spectral map (Figure f), corresponding to the AFM image in Figure e, the phase separation of the PS- b -PEO/4AzOH can also be observed.…”

Section: Resultsmentioning

confidence: 95%

“…22 Figure 3e shows the AFM phase image of a PS-b-PEO/4AzOH film, where the brighter and darker regions are the PS and PEO domains, respectively. 23 From the IR spectral map (Figure 3f), corresponding to the AFM image in Figure 3e, If the PS-b-PEO/4AzOH films are treated with the PA-SVA process at higher temperatures, the orientation kinetics may be faster. Besides, the PA-SVA process may also be combined with the dynamic solvent vapor annealing setup to accelerate the orientation of PS-b-PEO/4AzOH films to meet the need for manufacturing.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Photoinduced Alignment under Solvent Vapor Annealing (PA-SVA): Enhanced Ordering and Patterning in Block Copolymer Films

Tseng

Fan

Chang

et al. 2022

ACS Appl. Polym. Mater.

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In the past few decades, alignment control and directed self-assembly of block copolymer thin films have been widely investigated. Most approaches, however, require chemically or topographically prepatterned substrates, increasing the processing complexity. In this work, we present a facile strategy to form well-aligned block copolymer thin films by photoinduced alignment under solvent vapor annealing (PA-SVA) without chemically or topographically prepatterned substrates. Polystyrene-block-poly(ethylene oxide) (PS-b-PEO) consisting of two polymer blocks with distinct hydrophilicities and mechanical properties is incorporated with 4-butyl-4′-hydroxyazobenzene (4AzOH) to achieve the light-assisted self-assembly. Under solvent vapor annealing, the PS-b-PEO chains are swollen and possess mobilities. Upon polarized light irradiations, light-responsive azobenzene molecules undergo trans–cis–trans isomerization and achieve photoinduced alignment. The arrangement of the azobenzene molecules can further induce the alignment of the PS-b-PEO chains through supramolecular interactions between the phenol groups of the 4AzOH and the ether groups of the PEO chains. AFM-IR measurements are applied to characterize the selective blending of the 4AzOH molecules in the PEO segments. With different PA-SVA times, the transitions of the PS-b-PEO phase separation can be observed; the alignment of the PS-b-PEO/4AzOH films is further characterized by orientation analysis. The facile design of the PA-SVA strategy not only enables the manipulation of light-responsive molecules in block copolymer chains but also provides an alternative way for obtaining well-ordered block copolymer thin films.

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“…[38][39][40] One can generally expect that BCP materials with extremely different surface tensions (between the two blocks) will be difficult to order vertically, whereas materials with small surface tension differences should readily form vertical morphologies. Correspondingly, the differences in self-assembly behavior observed for the many different BCP materials that have been studied (which include PS-b-PMMA, 37,41 PS-b-polyvinylpyridine, 42 PS-b-polyisoprene, 43 and PS-b-poly(dimethyl siloxane) 21,44,45 ) must be due in part to the different surface tensions. Despite the importance of surface tension disparity to BCP ordering, this property has not been studied as carefully as other aspects of BCP thin films (such as segregation strength and substrate energy).…”

Section: Introductionmentioning

confidence: 99%