A layered liquid crystalline droplet

Zhao, Yanli; Erina, N. A.; Yasuda, Takuma; Kato, Takashi

doi:10.1039/b901917k

Cited by 7 publications

(6 citation statements)

References 55 publications

(62 reference statements)

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“…This is the typical asymmetric wetting structures for symmetric block copolymer thin films. 6,19,51,53,54 The thickness L of the second layer (part b of Figure 3) depends on the total molecular weight of the polymers and this compares well with other studies where an increase in the lamella thicknesses with increasing the M w of the diblock copolymer chain has been reported. 55 The asymmetric wetting behavior (affinity of PEO block with the mica substrate and segregation of PI at the free interface, due to its lower surface tension compared to the PEO counterpart) is also confirmed by the phase imaging of part c of Figure 4.…”

Section: ■ Results and Discussionsupporting

confidence: 88%

“…The terraced structures observed consisted from 4 up to 8 lamellar layers, with lamellar height L ≈ 26 nm which is approximately double of the thickness of the corresponding first monolayer ( L /2) as shown in the graph of part c of Figure as well as in the height profile of part d of Figure and in Figure S2 of the Supporting Information. This is the typical asymmetric wetting structures for symmetric block copolymer thin films. ,,,, The thickness L of the second layer (part b of Figure ) depends on the total molecular weight of the polymers and this compares well with other studies where an increase in the lamella thicknesses with increasing the M w of the diblock copolymer chain has been reported …”

Section: Resultssupporting

confidence: 87%

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Thin Films of Poly(isoprene-b-ethylene Oxide) Diblock Copolymers on Mica: An Atomic Force Microscopy Study

et al. 2013

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The structural behavior of three amphiphilic semicrystalline poly(isoprene-b-ethylene oxide) block copolymers (PI-b-PEO) with different PEO volume fraction (f(PEO) = 0.32, 0.49, and 0.66), spin-coated on freshly cleaved mica surfaces from aqueous solutions, was investigated by atomic force microscopy. We focus on the dependence of the resulting thin film nanostructures on the molecular characteristics (f(PEO) and molecular weight) and the adsorbed amount. The nanostructures obtained immediately after spin-coating were robust and remained unchanged after annealing and/or aging. The PEO affinity for the highly hydrophilic mica and the tendency of the hydrophobic and low surface energy PI to dewet and be at the free interface caused the soft PI-b-PEO micelles to collapse leading to the formation of 2D dendritic networks over mica. We show that, for all three polymers, the dendritic monolayer thickness can be predicted by a model consisting of a PEO crystallized layer (directly on top of mica) of the same thickness in all cases and a PI brush layer on top. In thicker areas, polymer material self-assembled into conelike multilamellar bilayers on top of the monolayer and oriented parallel to the substrate for both symmetric and asymmetric diblock copolymers with the lowest f(PEO). We compare the lateral morphology of the films and discuss the thickness heterogeneity, which results from the coupling and competition of crystallization kinetics, phase separation, and wetting/dewetting phenomena highlighting the role of the two blocks to inhibit or enhance certain morphologies. We show that the deviation of the f(PEO) = 0.32 thin film from its bulk phase structure (cylinders in hexagonal lattice) continues for several lamellar bilayers away from the substrate. For the asymmetric PI-b-PEO polymer with the higher PEO volume fraction (f(PEO) = 0.66) and higher APT, laterally extensive stacks of flat-on lamellar crystallites formed on the surface demonstrating the crucial role of the PEO crystallization.

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Section: ■ Results and Discussionsupporting

confidence: 88%

Section: Resultssupporting

confidence: 87%

Thin Films of Poly(isoprene-b-ethylene Oxide) Diblock Copolymers on Mica: An Atomic Force Microscopy Study

et al. 2013

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“…Stoddart et al have reported the gelation of a cholesterol stoppered dumbell containing 1,5-dioxynaphthalene as well as a bistable rotaxane 278 (Chart ) and cyclobis(paraquat- p -phenylene) rings in mixed solvent systems . The drop cast samples self-organize to form layered droplet superstructures consisting of a stack of concentric discs with increasing size . Ultrasound induced growth of helical fibers of 279 (Chart ) resulted in a chiral fluorescent organogel at relatively high temperatures or low concentrations …”

Section: Gelators Based On Fused Aromaticsmentioning

confidence: 99%

Functional π-Gelators and Their Applications

2014

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“…In practice, the spreading of amphiphilic molecules such as lipids [1], symmetric block copolymers [2], or liquid crystals [3][4][5][6] on solid surfaces in air is a major aspect in controlling the shape and behavior of very small volumes of materials on surfaces, which has presently important issues, such as surface vesicle fusion, surface patterning, elaboration of biomimetic membranes, microcontact printing [7,8], or biochip spotting [9]. In the case of phospholipids, most of the studies are conducted at the solid-liquid interface [10][11][12], because of the great potential of these molecules to make scaffolds for biochips [13][14][15].…”

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confidence: 99%

Mechanism of Lipid Nanodrop Spreading in a Case of Asymmetric Wetting

et al. 2012

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Using the surface enhanced ellipsometric contrast microscopy, we follow the last stage of the spreading of egg phosphatidylcholine nanodroplets on a hydrophilic substrate in a humid atmosphere, focusing on the vanishing trilayer in terraced droplets reduced to coexisting monolayer and trilayer. We find that the line interface between them exhibits two coexisting states, one mobile and one fixed. From there, it is possible to elucidate the internal structure and the spreading mechanism of the stratified liquid in a case of asymmetric wetting, i.e., where the lipid film is made of an odd number of leaflets.

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A layered liquid crystalline droplet

Cited by 7 publications

References 55 publications

Thin Films of Poly(isoprene-b-ethylene Oxide) Diblock Copolymers on Mica: An Atomic Force Microscopy Study

Thin Films of Poly(isoprene-b-ethylene Oxide) Diblock Copolymers on Mica: An Atomic Force Microscopy Study

Functional π-Gelators and Their Applications

Mechanism of Lipid Nanodrop Spreading in a Case of Asymmetric Wetting

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