Anisotropic Ionic Mobility of Lithium Salts in Lamellar Liquid Crystalline Polymer Networks

Abstract

New mesogens presenting smectic A (SmA) phases and capable of hosting lithium salts are designed. The mesogens comprise a vinyl-functionalized spacer to allow further reaction to the polymer backbone, an aromatic core and ethylene oxide chains, able to coordinate lithium ions. Copolymerizing these monomers with a suitable crosslinker yields the first lithium containing liquid crystalline elastomers (LCEs). The SmA structure where the ethylene oxide chains are microphase separated in layers is fixed by the crosslinking and permanent macroscopic orientation is obtained. Diffusion and conductivity measurements of the monomer sample show a large anisotropy of the ion mobility (100 for the cation and 400 for the anion). In the elastomer the anisotropy of the lithium mobility is comparable to that in the monomers.

Nanoporous Polymers Based on Liquid Crystals

“…Smectic liquid crystals have the benefit that they can be aligned using well-known alignment techniques [ 65 ], typically used in the liquid crystal display industry. Traditionally, ion conducting membranes have been prepared from either low molecular weight smectic liquid crystals [ 66 , 67 , 68 , 69 , 70 ], or from polymers [ 33 , 71 ]. Although these materials show unique anisotropic ionic conducting properties, they have a low degree of porosity and mechanical strength.…”

“…Because of its speed and robustness, photo-initiated free radical polymerisation of acrylates/methacrylates is probably the most frequently applied method for fixating LC morphologies [ 23 , 24 ]. However, there are many alternative fixation methods available to obtain LC networks, including acyclic diene metathesis (ADMET) [ 25 , 26 , 27 ], thiol- ene chemistry [ 28 ], cationic polymerization of epoxides [ 29 ], coumarin dimerization [ 30 ], free radical polymerization of dienes [ 31 ], and hydrosilylation of alkenes [ 32 , 33 ]. Upon polymerisation, highly cross-linked networks can be obtained.…”

An all solid-state Li ion battery composed of low molecular weight crystalline electrolyte

“…Therefore, there has been a need to seek for an altogether new ion conductive mechanism [17][18][19] that is different from ordinary polymer electrolytes. This has led to the development of several novel and interesting materials.…”

Ionic conductivity probed in main chain liquid crystalline azobenzene polyesters

“…[5][6][7][8][9][10][11][12] The oligoethylene oxide segment can bind to alkali metals through ion-dipole interactions, which can stabilize as well as induce various self organized LC phases. [13][14][15][16][17][18][19] For instance, a rod coil polymer containing PEO upon complexation with LiCF 3 SO 3 exhibited phase transitions from the highly ordered smectic phase followed by cubic and finally cylindrical micellar mesophase upon increasing Li ion salt concentration. 20 However, the PEO-salt complexes have a natural tendency for crystallization, which retards effective ion transport through polymer matrix.…”

“…H-NMR and 13 C-NMR spectra of polymers were recorded on a Bruker-AVANCE 200 MHz spectrometer using CDCl 3 as solvent. The molecular weight of the polymers was determined using a Polymer Laboratories PL-GPC-220 Gel Permeation Chromatography (GPC) with CHCl 3 as eluent.…”