Combined main-chain/side-chain ionic liquid crystalline polymer based on ‘jacketing’ effect: Design, synthesis, supra-molecular self-assembly and photophysical properties

Abstract

Ionic liquid crystalline polymers (ILCPs) are a class of macromolecular architectures with mesogenic groups and ionic species and they have attracted great interest in the fields of polymer chemistry and materials science lately [1][2][3]. The combination of electrostatic interaction with liquid crystalline (LC) ordering yields ILCPs with excellent mechanical properties, rheological processability, piezoelectric performance, and optical variable performance [1][2][3][4][5][6][7]. Generally, ionic interaction promotes the ILCPs to form ionic clusters resulting in a reversible physical gelation [1,8,9]. Moreover, incorporation of the ions and selection of the type of ion chemistry can effectively improve the miscibility with other polymers. Therefore, ILCPs are versatile candidates to construct new high-performance functional mate- 536Combined main-chain/side-chain ionic liquid crystalline polymer based on 'jacketing' effect: Design, synthesis, supra-molecular self-assembly and photophysical properties Abstract. Reasonably fabricating ordered structures of ionic polymers is very important for the development of novel functional materials. By combining the ions and liquid cry stalline polymer, we successfully designed and synthesized a series of novel combined main-chain/side-chain ionic liquid crystalline polymer (MCSC-ILCPs) containing imidazolium groups and different counter-anions, poly (2,5-bis{[6-(4-butoxy-4!-imidazolium biphenyl)hexyl]oxycarbonyl}styrene salts) poly(BImBHCS-X) with the following types of counter-anions (Br", BF 4 ", PF 6 " and TFSI"). Combined technologies confirmed the chemical structures of the monomers and polymers with imidazolium cation and different counter-anions. Differential scanning calorimetry (DSC), polarized light microscopy (PLM) and one-and two-dimensional wide-angle X-ray diffraction (1D and 2D WAXD) results illustrated that the LC structures and the transitions of ordered structures depended on the nature of the counter-anion employed. The polymers with Br" and BF 4 " counter-anions exhibited smectic A (SmA) LC behavior below the isotropic temperature. The another one, poly(BImBHCS-TFSI) with the large volume of the TFSI" anion destroyed the packing of the LC ordered structure resulting in an amorphous structure. The photophysical properties of the polymers prepared can be adjusted by tuning the ionic interaction of the polymers by switching the counter-anion.

Synthesis of ionic polymers by free radical polymerization using aprotic trimethylsilylmethyl‐substituted monomers

“…Ionic polymers are generally synthesized either by solution polymerization of various ionic monomers or bulk polymerization in the case that ionic liquid monomers are applied . Ionic liquid monomers are ionic liquids that are substituted with a polymerizable functional group.…”

Main‐chain ionic liquid‐crystalline polymers bearing quaternary phosphonium ions

“…It has been reported that the liquid‐crystalline behavior of ILCs depends on the nature of the cations and anions that the ILCs have . Some typical cations ILCs with pyridinium, imidazolium, pyrrolidinium, quaternary ammonium, and quaternary phosphonium salts have been reported, as well as anions ILCs with BF 4 − , PF 6 − , CF 3 SO 3 − , and so on . These organic cations and organic/inorganic anions interact via electrostatic and other noncovalent interactions rather than covalently bound .…”