Microdomain Orientation of Star-Shaped Block Copolymer Thin Film Depending on Molecular Weight

Park, So Yeong; Choi, Chungryong; Lee, Kyu Seong; Kim, Eunseol; Ahn, Seonghyeon; Lee, Jae Yong; Kim, Jin Kon

doi:10.1021/acs.macromol.0c00403

Cited by 7 publications

(12 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, we found that Cut-ST1 showed a disordered state. This is ascribed to the fact that the predicted critical (χ N ) S for the formation of lamellar microdomains in the six-arm star-shaped block copolymer is lower than that of the corresponding linear diblock copolymer . L1 to L4 with f PMMA ∼0.5 showed lamellar microdomains, while L5 with f PMMA = 0.72 and L6 with f PMMA = 0.85 exhibited hexagonally packed cylindrical and body-centered cubic (BCC) packed spherical microdomains, respectively (Figure S3).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Inverted Cylindrical Microdomains by Blending Star-Shaped and Linear Block Copolymers

et al. 2021

Self Cite

View full text Add to dashboard Cite

We investigated the morphology formed in the binary blend of six-arm star-shaped (poly(methyl methacrylate)-block-polystyrene)6 copolymer [(PMMA-b-PS)6] and PMMA-b-PS linear diblock copolymer by varying their molecular weights as well as volume fractions of the blocks. When the molecular weight of PMMA-b-PS is much larger (> ∼4) than that of one arm of (PMMA-b-PS)6, PMMA-cylindrical microdomains are formed even though the volume fraction of PMMA (f PMMA) in both (PMMA-b-PS)6 and PMMA-b-PS is nearly symmetric (f PMMA ∼0.5). On the other hand, when the ratio of molecular weights between these two copolymers is not large, lamellar morphology is observed in the blend as expected. Very interestingly, we found that even for a binary blend with the overall volume fraction of the PMMA block (f̅ PMMA) as large as 0.71, the major PMMA blocks still aggregate into cylindrical microdomains, and thus, “inverted cylinders” are formed, although PS-cylinders are observed in the neat (PMMA-b-PS)6 and PMMA-b-PS melts. This interesting inverted cylinder is mainly stabilized by two factors. On the one hand, the long linear diblock copolymer swells the domain significantly, thus preventing the short (PMMA-b-PS)6 star copolymer from forming the favorable bridging configurations in order to avoid the high stretching energy. As long as the bridging configurations are prohibited, the PMMA-core blocks of (PMMA-b-PS)6 prefer to stay inside the curvature, amplifying the tendency of forming a spontaneous curvature toward PMMA-blocks. On the other hand, the radial distribution of the long PMMA-block of the diblock and the short PMMA-block of the star increases the spontaneous curvature. The experimental results as well as the formation of the inverted cylinders have been verified by self-consistent field theory (SCFT).

show abstract

Section: Resultsmentioning

confidence: 99%

“…Then, the six-arm PMMA macroinitiator [(PMMA-Br) 6 ] was synthesized by atom transfer radical polymerization (ATRP). Finally, (PMMA- b -PS) 6 was synthesized from (PMMA-Br) 6 by ATRP . The molecular weights of PMMA and PS blocks were controlled by reaction time.…”

Section: Methodsmentioning

confidence: 99%

Inverted Cylindrical Microdomains by Blending Star-Shaped and Linear Block Copolymers

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Compared to diblock copolymers, ABA triblock copolymers offer advantages in thin-film assembly. Both theoretical and experimental studies indicate that linear ABA triblock copolymers have a higher tendency toward forming perpendicular nanostructures. − When the midblock B has lower surface energy and forms a wetting layer at the air interface, the higher surface energy A end blocks are likely to migrate to the air interface due to the greatly increased end-segment entropy. − Triblocks have been reported to have a larger processing window in a thin film compared to their analogous diblocks. − They are known to form smaller features than that of diblocks with similar molecular weights and to potentially self-assemble into even smaller critical dimensions as they exhibit a lower (χ N ) ODT value at roughly 9.9. ,− The unique bridging conformation in an ordered phase also enhances the ABA triblock mechanical properties significantly. , …”

Section: Introductionmentioning

confidence: 99%

Synthesis of High Etch Contrast Poly(3-hydroxystyrene)-Based Triblock Copolymers and Self-Assembly of Sub-5 nm Features

2021

View full text Add to dashboard Cite

We demonstrate the successful synthesis of a series of poly(3-hydroxystyrene)-block-poly(dimethylsiloxane)-block-poly(3-hydroxystyrene) (P3HS-b-PDMS-b-P3HS) triblock copolymers by atom transfer radical polymerization (ATRP). This system is a promising candidate for pattern transfer of single-digit nanometer features, due to its intrinsic high etch contrast, etch versatility, and the triblock architecture. Hydroxy-terminated PDMS polymers were directly functionalized to initiate the ATRP of an acetal-protected 3-hydroxystyrene monomer. The resulting triblocks have dispersity ranging from 1.10 to 1.26, and the synthesis provides robust control over molecular weights and volume fractions. The large chemical incompatibility between the blocks enabled the formation of ordered structures at low molecular weights, which yielded lamellar periodicities as small as 9.3 nm. This triblock hence permits access to sub-5 nm feature sizes. The phase diagram is asymmetric, with lamellar morphologies observed at lower volume fractions of the P3HS block, relative to the diblocks. This asymmetry is ascribed to the dispersity of the middle block relative to the end blocks.

show abstract

“…This reveals that a higher molecular weight can enhance the driving force inducing the perpendicular orientation of microdomains. This result is in agreement with the previous report …”

mentioning

confidence: 99%

“…The molecular weight of PS blocks is determined by gel permeation chromatography (GPC), and the molecular weight and volume fraction of the PLLA block ( f v PLLA/PLA ) are measured by 1 H NMR (Figures S1 and S2 and Table S1). To examine the precise molecular weight of the PS segment in star-shaped BCPs*, the ester groups of multihead initiator were cleaved by hydrolysis in a basic condition . In this work, the compositions of BCPs* are controlled in the range that would lead to the formation of H* phases …”

mentioning

confidence: 99%

Confined Self-Assemblies of Chiral Block Copolymers in Thin Films

et al. 2021

View full text Add to dashboard Cite

Self-assembly of chiral block copolymers (BCPs*) can give rise to ordered chiral nanostructures, that is, a helical phase (H* phase), via chirality transfer from the molecular level to mesoscale. In the present work, we reported the self-assembly of BCPs* under one-dimensional spatial confinement. The morphological dependence of self-assembled BCPs* on the molecular weights and the film thickness was investigated. As chiral nanostructures, the H* phase can be formed in bulk, nonchiral nanostructures that were observed in the thin films. Also, the topology effect of self-assembly of BCPs* was examined. The self-assembly of BCPs* with a star-shaped topology exhibited a distinct morphology compared with that of linear BCPs*. The present work provides new insight into the chirality transfer of macromolecules under spatial confinement.

show abstract

Microdomain Orientation of Star-Shaped Block Copolymer Thin Film Depending on Molecular Weight

Cited by 7 publications

References 38 publications

Inverted Cylindrical Microdomains by Blending Star-Shaped and Linear Block Copolymers

Inverted Cylindrical Microdomains by Blending Star-Shaped and Linear Block Copolymers

Synthesis of High Etch Contrast Poly(3-hydroxystyrene)-Based Triblock Copolymers and Self-Assembly of Sub-5 nm Features

Confined Self-Assemblies of Chiral Block Copolymers in Thin Films

Contact Info

Product

Resources

About