Novel Supramolecular Side-Chain Banana-Shaped Liquid Crystalline Polymers Containing Covalent- and Hydrogen-Bonded Bent Cores

Abstract

Novel supramolecular side-chain banana-shaped liquid crystalline (LC) polymer complexes AmBn-N bearing various (m/n) molar ratios of hydrogen-and covalent-bonded bent-core components were acquired by the free radical polymerization, where the hydrogen-bonded (H-bonded) structures were executed via mixing equimolar portions of proton donor (H-donor) polymers AmBn (homopolymers/ copolymers) and pyridyl proton acceptor (H-acceptor) bent cores (small molecules). The influences of the molar ratios of bent-core H-bonded components in side-chain banana-shaped LC polymers and their corresponding polymer complexes on mesomorphic and electro-optical properties were first investigated. The voltage-dependent antiferroelectric properties of spontaneous polarization (Ps) values in the polar smectic phase of the supramolecular side-chain banana-shaped copolymers were also reported. The nematic and tilted smectic phases were verified by XRD measurements, and the SmCP phase was further confirmed by the triangular wave method. Surprisingly, a novel enantiotropic polar smectic (SmCP A ) phase was generated in some bent-core side-chain polymer complexes AmBn-N. Therefore, a special approach to constructing (or stabilizing) the SmCP phase was first developed in this study by copolymerization of bent-core covalent-and H-bonded units in side-chain polymer complexes (with proper m/n molar ratios of 16/1 and 10/1) from both bent-core covalent-and H-bonded monomers (i.e., B and A-N units, respectively) without the SmCP phase.

Side Chain Liquid Crystalline Polymers: Advances and Applications

“…LCPs are a special class of polymer that shows liquid crystal phase (Wang and Zhou 2004). When LC meets polymers, the resulting LCPs show anisotropic and isotropic properties, which originate from the mesogenic units and good mechanical properties, which come from long-chain structures (Wang and Zhou 2004).…”

“…When LC meets polymers, the resulting LCPs show anisotropic and isotropic properties, which originate from the mesogenic units and good mechanical properties, which come from long-chain structures (Wang and Zhou 2004). Over the last few decades, LCPs have attracted considerable research attention, owing to their wide applications as engineering plastics, electro-optic or nonlinear optic materials, stationary phases, high-strength and high-modulus fibers and their use as gas separation membranes, etc.…”

“…Therefore, the developments of BCLC material into polymeric molecules are interesting research topics that explore potential useful applications. Generally, most of the bent-shaped polymers are reported as main-chain (Gimeno et al 2011;Choi et al 2010) as well as side-chain polymers (Chen et al 2007a, b;Wang et al 2010;Kishore et al 2009). The side-chain bent-core polymers are derived from 1,3-phenylene unit with five aromatic rings, which can be symmetric (Wang et al 2010) as well as asymmetric (Kishore et al 2009), wherein the polymerizable functional groups are generally used, are 1,3-diene (Sentman and Gin 2003), methacrylates or acrylates group (Chen et al 2007a, b) and siloxane group (Keith et al 2005).…”

“…Generally, most of the bent-shaped polymers are reported as main-chain (Gimeno et al 2011;Choi et al 2010) as well as side-chain polymers (Chen et al 2007a, b;Wang et al 2010;Kishore et al 2009). The side-chain bent-core polymers are derived from 1,3-phenylene unit with five aromatic rings, which can be symmetric (Wang et al 2010) as well as asymmetric (Kishore et al 2009), wherein the polymerizable functional groups are generally used, are 1,3-diene (Sentman and Gin 2003), methacrylates or acrylates group (Chen et al 2007a, b) and siloxane group (Keith et al 2005). Interestingly, side-chain bent-core liquid crystalline polymers predominantly demonstrate rich mesomorphism when compared with the main-chain (Saravanan et al 2008), side-chain (Saravanan and Kannan 2010) and dendronized liquid crystalline polymers Percec 2007, 2008;Rosen et al 2009;) are classified as follows: (i) side-chain bent-core liquid crystalline polymer (SBCLCPs), (Chen et al 2007a, b;Srinivasan et al 2013b) (ii) bentcore mesogen-jacketed liquid crystalline polymers (BMJLCPs) ), (iii) central linked bent-core liquid crystalline polymer (CBCLCPs) (Srinivasan and Kannan 2011) and (iv) hydrogen-bonded side chain bent-cores liquid crystalline polymers (HBCLCPs) (Wang et al 2010), were reported based on the polymeric back bone attached to the position of bent-core mesogen pendant.…”

Photo and electrically switchable behavior of azobenzene containing pendant bent‐core liquid crystalline polymers

“…Hence, the developments of BCLC material in to polymeric molecules are the interesting research topic utilitarian in potential application. In general, most of the bent‐shaped polymers are reported as main‐chain21,22 as well as side‐chain polymers 23–25. The side‐chain bent‐core polymers are derived from 1,3‐phenylene unit with five aromatic rings, symmetric24 as well as asymmetric,25 wherein the polymerizable functional groups are generally used as 1,3‐diene,26 methacrylates or acrylates group,23 and siloxane group 27.…”