Main-chain liquid-crystalline elastomers

Finkelmann reported synthesis of a novel cross-linked smectic-C main-chain liquid-crystalline elastomer that was formed by polycondensation of vinyloxy-terminated mesogens, tetramethyldi-siloxane, and pentamethyl-pentaoxapentasilicane. The introduction of the functional vinyloxy group allows the synthesis of well-defined networks with good mechanical properties due to ehmination of side reactions as in the case of vinyl groups [60]. [Pg.47]

LIQUID-CRYSTALLINE POLYMERS 3.4.1 Main-Chain Liquid-Crystalline Elastomers... [Pg.35]

Yang H, Buguin A, Taulemesse J-M, Kaneko K, Mdry S, Bergeret A, Keller P (2009) Micron-sized main-chain liquid crystalline elastomer actuators with ultralarge amplitude contractions. J Am Chem Soc 131(41) 15000-15004. doi 10.1021/ja905363f... [Pg.84]

Sanchez-Ferier A, Finkelmaim H (2009) Thermal and mechanical properties of new main-chain liquid-crystalline elastomers. Mol Cryst Liq Cryst 508 348-356. doi 10.1080/ 15421400903065861... [Pg.86]

Rogez D, Francius G, Finkelmann H, Martinoty P (2006a) Shear mechanical anisotropy of side chain liquid crystal elastomers influence of sample preparation. Eur Phys J E 20 369-378 Rogez D, Brandt H, Finkelmann H, Martinoty P (2006b) Shear mechanical properties of main chain liquid crystalline elastomers. Macromol Chem Phys 207 735-745... [Pg.67]

Donnio B, Wermter H, Finkelmann H (2000) A simple and versatile synthetic route for the preparation of main-chain liquid-crystalline elastomers. Macromolecules 33 7724—7729 Finkelmann H (1987) Liquid crystal polymers. Chap 1. In Gray GW (ed) Thermotropic liquid crystals. Wiley, Chichester, pp 1-27... [Pg.456]

Fig. 5. Sketch showing stress-strain isotherms for a main-chain liquid-crystalline elastomer such as poly(diethylsiloxane), as a function of the amount of mesophase present.

Only comparatively few dynamic mechanical measurements in the vicinity of the nematic-isotropic transition have been reported these include some for side-chain liquid crystalline elastomers [7, 8], and some for liquid crystalline elastomers with mesogenic groups in the main chains and in the side-chains (combined LCE) [9]. The latter reference describes the evaluation of... [Pg.278]

Compared to side chain elastomers the preparation of main chain elastomers with suitable transition temperatures is rather challenging. What is more, due to the rigid rod-like mesogenic moieties in the polymer main chain, most linear main chain liquid crystalline polymers exhibit high clearing temperatures and tend to crystallize [23], making them unfavorable for many LC elastomer applications. [Pg.11]

Liquid crystalline polymers are classified either as main-chain liquid crystalline polymers (MCLCP), as polymers with mesogen-ic side groups (SGLCP), or as liquid crystalline elastomers. [Pg.56]

Sanchez-FerrCT A, Finkehnann H (2013) Opto-mechanical effect in photoactive nematic main-chain liquid-erystalline elastomers. Soft Matter 9 46214627 Sanchez-FerrCT A, Merekalov A, Finkehnann H (2011) Opto-mechanical effect in photoactive nematic side-chain liquid-crystalline elastomers, macromol. Rapid Commun 32 671-678 Shankar MR, Smith ML, Tondiglia VP, Lee KM, McConney ME, Wang DH, Tan LS, White TJ (2013) Cmitactless, photoinitiated snap-through in azobenzene-functionalized polymtas. Proc Natl Acad Sci 110 18792-18797... [Pg.457]

Inspired by the spider silk, which is among the toughest natural materials, Pollock and Hammond [47] prepared an interesting silk-like thermoplastic polyurethane elastomer with main-chain liquid crystalline soft segments (Schemes 41-43). [Pg.52]

Properties have been determined for a series of block copolymers based on poly[3,3-bis(ethoxymethyl)oxetane] and poly [3,3-bis(methoxymethyl)oxetane]-(ro-tetrahydrofuran. The block copolymers had properties suggestive of a thermoplastic elastomer (308). POX was a good main chain for a well-developed smectic liquid crystalline state when cyano- or fluorine-substituted biphenyls were used as mesogenic groups attached through a four-methylene spacer (309,310). Other side-chain liquid crystalline polyoxetanes were observed with a spacer-separated azo moiety (311) and with laterally attached mesogenic groups (312). [Pg.368]

In the preceding chapters the synthesis properties of linear liquid crystalline polymers are described, where different approaches exist to obtain the liquid crystalline state rod-like or disc-like mesogenic units are either incorporated in the polymer backbone or are attached as side groups to the monomer units of the main chain. Following conventional synthetic techniques these linear polymers can be converted to polymer networks. Compared to low molar mass liquid crystals and linear liquid crystalline polymers, these liquid crystalline elastomers exhibit exceptional new physical and material properties due to the combination and interaction of polymer network elasticity with the anisotropic liquid crystalline state. [Pg.277]

Zen tel R, Reckert G. 1986. Liquid crystalline elastomers based on liquid crystalline side group, main chain and combined polymers. Makromol Chem 187 1915 1926. [Pg.144]

The first example of a neat liquid crystalline elastomer appeared in the literature in 1981 (Finkelmann et al.) [7] and was based upon side-chain LCPs. Semi-flexible main-chain-based LC networks were also reported later in 1986 by Zental and Reckert [8]. [Pg.267]

Zentel, R. Reckert, G., Liquid Crystalline Elastomers Based on Liquid Crystalline Side Group, Main Chain and Combined Polymers. Makromol. Chem. 1986, 187,1915-1926. [Pg.56]

Malucelli and co-workers succeeded in preparing shape memory main-chain nematic coatings, by photopolymerizing liquid crystalline elastomers eventually subjected to uniaxial stress. To this aim, a mesogenic diglycidyl-terminated... [Pg.212]

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