Order in Thin Films of Side-Chain Liquid-Crystalline Polymers

Wielen, M.W.J. van der; Stuart, M.A. Cohen; Fleer, G.J.; Boer, Dick K. G. de; Leenaers, A.; Nieuwhof, R.P.; Marcelis, Antonius T. M.; Sudhölter, Ernst J. R.

doi:10.1021/la970243d

Cited by 31 publications

(31 citation statements)

References 8 publications

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“…Compared with the vast amount of studies for amorphous and crystalline (LC) polymers, studies on the anomaly in structure and orientation of side chain liquid crystalline polymers in ultrathin film states are rather unexplored. However, some significant data have been reported. − Henn et al discussed the orientational change in mesogens of a smectic polymer at a ultrathin film state by X-ray reflectometry measurements. They observed that the homeotropically aligned rod mesogens becomes planar for films below 10 nm when the film is in the smectic C* phase.…”

Section: Introductionmentioning

confidence: 99%

Evaluations of Mesogen Orientation in Thin Films of Polyacrylate with Cyanobiphenyl Side Chain

Tanaka¹,

Mizuno²,

Hara³

et al. 2016

Langmuir

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The orientation behavior of mesogens in a polyacrylate with cyanobiphenyl (CB) side chain in thin films was investigated in detail by UV-vis absorption spectroscopy and grazing incidence small-angle X-ray scattering (GI-SAXS) measurements using both high-energy X-rays of Cu Kα line (λ = 0.154 nm) and low-energy synchrotron X-rays (λ = 0.539 nm). By changing the film thickness ranging 7-200 nm, it is concluded that the planar orientation is predominant for thin films with thickness below 10-15 nm. This planar mesogen orientation near the substrate surface coexists with the homeotropically aligned CB mesogens in films thicker than 30 nm. For the thinnest 7 nm film, the planar orientation is unexpectedly lost, which is in consort with a disordering of smectic layer structure. Peculiar orienting characteristics of CB mesogen are suggested, which probably stem from the tendency to form an antiparallel arrangement of mesogens due to the strong dipole moment of the terminal cyano group.

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Section: Introductionmentioning

confidence: 99%

Evaluations of Mesogen Orientation in Thin Films of Polyacrylate with Cyanobiphenyl Side Chain

Tanaka¹,

Mizuno²,

Hara³

et al. 2016

Langmuir

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“…It has been found that the dewetting process strongly depended on the molecular structure properties 52, 53. Lee et al has reported the solvent‐driven dewetting of PS and the rim instability 42.…”

Section: Resultsmentioning

confidence: 99%

Multiscale dewetting of triblock copolymer thin film induced by solvent vapor

Zhu

Zhao

Liao

et al. 2005

J Polym Sci B Polym Phys

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Multiscale dewetting of poly(styrene‐b‐ethylene/butylenes‐b‐styrene) (SEBS) triblock copolymer thin films induced by volatile solvent vapor treatment were observed in this study. Film rupture occurred at first and produced macroscopic holes. Near‐regular droplets (which represented a compromise between complete disorder and perfect order) could be formed at the last stage. The mechanism of solvent‐driven dewetting was discussed by comparing with that of thermal‐induced dewetting. Similar to thermal‐induced dewetting, the block copolymer thin films initially break up through the nucleation of holes that perforated the films. The rapid growing holes became unstable and formed nonequilibrium fingering patterns. The films exhibit autophobic or autodewetting phenomena. The velocity of the holes growth was nearly a constant (3.3 μm/min). The stages of the dewetting were quite similar to that found for homopolymer and block copolymer thin films dewetting on solid or liquid substrates under thermal treatment. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2874–2884, 2005

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“…Therefore, in addition to ordinary linear polymers, end-functionalized polymer, block copolymers, − star polymers, and ring polymers are also interesting class of polymer materials for dewetting processes. Additionally, the dewetting behavior of LC polymers has aroused another interest, i.e., a hierarchical LC-ordered structure involved during the dewetting process. − …”

Section: Introductionmentioning

confidence: 99%

Formation of High-Density Brush of Liquid Crystalline Polymer Block Associated with Dewetting Process on Amorphous Polymer Film

et al. 2019

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The understanding of polymer dewetting on solid surfaces is significant in both fundamental polymer physics and practical film technologies. When liquid crystalline (LC) polymers are dewetted, LC ordering is involved in the dewetting process. Here, we report on the characteristic dewetting processes of a diblock copolymer composed of a cyanobiphenyl side chain liquid crystalline polymer (SCLCP) block connected with polystyrene (PS) taking place on a PS base film. Thin films of the block copolymer were prepared by the water-floating method onto the PS film, and the dewetting process is observed in a softened state above the glass transition temperature of the PS. At the smectic A phase temperature of the SCLCP block, the dewetted surface layer generated a flat unique fingering pattern leading to a monolayered (two-dimensional) highdensity LC polymer brush through the LC ordering. The important role of the anchoring PS block on the base PS film surface is suggested for the formation of highly stretched LC polymer brush. Above the isotropization temperature, in contrast, ordinary three-dimensional droplet morphologies with smooth round edges were observed. By photo-cross-linking the base PS film, the lateral diffusion rate was significantly reduced. This can be applied to an entropy-driven morphology patterning via dewetting. The polymer brush formation and its spatial controls are expected to provide new opportunities for the modification strategies of polymer surfaces.

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Order in Thin Films of Side-Chain Liquid-Crystalline Polymers

Cited by 31 publications

References 8 publications

Evaluations of Mesogen Orientation in Thin Films of Polyacrylate with Cyanobiphenyl Side Chain

Evaluations of Mesogen Orientation in Thin Films of Polyacrylate with Cyanobiphenyl Side Chain

Multiscale dewetting of triblock copolymer thin film induced by solvent vapor

Formation of High-Density Brush of Liquid Crystalline Polymer Block Associated with Dewetting Process on Amorphous Polymer Film

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