On the thread-like morphology of LC/I block copolymers in nematic solvents

Walther, Mathias; Faulhammer, Heike; Finkelmann, Heino

doi:10.1002/(sici)1521-3935(19980201)199:2<223::aid-macp223>3.0.co;2-x

Cited by 39 publications

(24 citation statements)

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“…The structure formation of liquid-crystalline isotropic AB block copolymers in nematic solvents was first reported by Finkelman et al [255,256]. These authors have shown that block copolymers consisting of a 'nematophilic' liquid-crystalline block and a 'nematophobic' segment are able to form thermoreversible thread-like aggregates of micellar type with ordered superstructure in dilute nematic solvents.…”

Section: Micellar Architectures Derived From Linear Ab and Aba Block mentioning

confidence: 90%

Micellization of block copolymers

Riess¹

2003

Progress in Polymer Science

1,870

1,787

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This article deals with recent progress including the author's work in the field of block copolymer self-assembly in solution and on solid surfaces. The synthesis methods for producing block copolymers with well-defined structures, molecular weights and composition are outlined with emphasis on ionic and controlled free radical polymerization techniques. A general overview of the preparation, characterization and theories of block copolymer micellar systems is presented. Selected examples of micelle formation in aqueous and organic medium are given for di-and triblock copolymers, as well as for block copolymers with more complex architectures. Current and potential application possibilities of block copolymer colloidal assemblies as stabilizers, flocculants, nanoreservoir in, among others, controlled delivery of bioactive agents, catalysis, latex agglomeration and stabilization of non-aqueous emulsion are also discussed.

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Section: Micellar Architectures Derived From Linear Ab and Aba Block mentioning

confidence: 90%

Micellization of block copolymers

Riess¹

2003

Progress in Polymer Science

1,870

1,787

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“…Azobenzene‐containing polymers are potentially useful for constructing photo‐responsive self‐assembling system using cis – trans isomerization 2. However, there are few examples of living polymerization of azobenzene‐containing momomers,3–6 although there have been numerous reports on the synthesis and properties of azo polymers 7. Especially, post‐polymerization reactions were required in cationic polymerization to prepare azo polymers with narrow molecular weight distribution (MWD) 6.…”

Section: Introductionmentioning

confidence: 99%

Photo‐responsive copolymers with azobenzene side groups synthesized by living cationic polymerization: Efficient amplification of photosensitivity in aqueous photo‐switching system

Yoshida

Kanaoka

Aoshima

2005

J. Polym. Sci. A Polym. Chem.

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Random and block copolymers of 4‐[2‐(vinyloxy)ethoxy]azobenzene (AzoVE) and various vinyl ethers (exhibiting LCST‐type phase separation) were prepared by living cationic polymerization using 1‐(isobutoxy)ethyl acetate/Et1.5 AlCl1.5 in the presence of ethyl acetate at 0 °C. With random copolymers having thermally‐responsive and azobenzene units, the phase separation occurs at a higher temperature under UV irradiation compared with that under visible light. This shift made it possible to control the solubility of the polymer by irradiating UV or visible light. Irradiation of a 20 wt % aqueous solution of (AzoVE2‐r‐EOEOVE200)‐b‐MOVE400 with visible light caused rapid gelation to give a transparent gel at 42.6 °C. Under subsequent irradiation with UV light, the gel returned to a fluid state with the same viscosity of the initial solution.

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“…Usually PMMAZO exhibits a smetic A LC structure at room temperature. 65 Upon heating, the smetic A phase rst transforms into a nematic phase and the transition temperature is indicated as T S-N . When it is further heated, the nematic phase may become isotropic at a transition temperature of T N-I .…”

Section: Polymerization Resultsmentioning

confidence: 99%

Hierarchical self-assembly, photo-responsive phase behavior and variable tensile property of azobenzene-containing ABA triblock copolymers

et al. 2015

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A series of triblock copolymers with liquid crystalline (LC) poly{6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate} (PMMAZO) as the end blocks and rubbery poly(n-butyl acrylate) (PnBA) as the midblock were synthesized. The effect of the interplay between the LC ordering and microphase separation on the hierarchical assembly of the triblock copolymers was studied. It is found that microphase separation at a larger scale can affect the LC ordering at a smaller scale, such as the stacking of the LC moieties, LC temperature and the domain size of the LC phase. On the other hand, alteration of the LC ordering, such as isotropization and smetic-to-nematic transition, may also lead to an order-order transition (OOT) or change in the long period of the microphase-separated structure. UV light can trigger the isomerization of the azobenzene LC moieties, which can be further amplified and exerts an effect on the microphase separation behavior, including the regularity of the microphase-separated structure and the OOT. The triblock copolymers also exhibit light-variable tensile properties. The results reveal that the phase behavior and mechanical properties of this type of triblock copolymer can be readily regulated by light, thus it may be used as smart and functional thermoplastic elastomer.

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On the thread-like morphology of LC/I block copolymers in nematic solvents

Cited by 39 publications

References 0 publications

Micellization of block copolymers

Micellization of block copolymers

Photo‐responsive copolymers with azobenzene side groups synthesized by living cationic polymerization: Efficient amplification of photosensitivity in aqueous photo‐switching system

Hierarchical self-assembly, photo-responsive phase behavior and variable tensile property of azobenzene-containing ABA triblock copolymers

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