Structural behaviour of thermotropic liquid crystals from poly(4‐vinylpyridine) fully and partially quaternized with a mesogenic group

Abstract

Liquid crystals were obtained from poly(4-vinylpyridine) quaternized with 1-bromooctane and 1-bromododecane w-substituted with 4'-methoxy-4-biphenyloxy mesogenic groups. Their thermotropic polymorphism was studied by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. Three types of smectic mesophase, namely A, B, and E, were identified and described from a structural point of view. Their structure was found to be very similar to that previously reported for their monomer counterparts. The mesogenic pendant groups are arranged in single layers with the polymer backbones inserted in between. As a function of decreasing degree of quaternization, the smectic period increases slowly, reflecting the expansion of the sublayers containing the polymer backbones along with the free pyridine rings.

Effect of smectogenicity of the ionic groups on the thermotropic liquid crystalline behavior of pyridinium and poly(4-vinylpyridinium) salts quaternized with mesogenic groups

“…Conmolecules laterally arranged head to tail, with the anions sandwiched between the pyridinium rings. cerning the smectic E structure, Navarro et al 2 had proposed a model of organization in which…”

“…The ionic LC polymers were first obtained by quaternization of poly(4-vinylpyri-A new class of side chain liquid crystalline dine ) with ( 4-methoxy-4 -biphenylyloxy ) alkyl (SCLC) polymers incorporating ionic groups in halide mesogenic groups or by spontaneous polythe side chains or in the skeleton were synthemerization of 4-vinylpyridine in the presence of sized and studied in our laboratory [1][2][3][4][5] together the same mesogenic moieties. 1,2 More recently, with various analogous monomers.…”

Solvent Manipulation of Liquid Crystal Order and Other Properties in Azo‐Containing Surfactomesogen/Poly(styrene sulfonate) Complexes

“…[25] The latter pattern, reported a number of times in the literature, is generally ascribed to extinction of the first-order peak by an additional plane of symmetry in the electron density profile along the lamellar normal. [18,25,[33][34][35][36][37][38][39] Assuming that the most intense diffraction peak for the polar-tailed complexes is indeed a second-order reflection, it was observed that all of the liquid crystalline complexes had a periodicity close to a single extended molecular length of the repeat unit (considering that the ion pairs can be arranged either parallel or perpendicular to the molecular long axis), thus indicating effectively single-layer SmA phases.…”

Ferrocene-Containing Thermotropic Side-Chain Liquid-Crystalline Polysiloxanes

“…The overall layer thickness is the sum of the siloxane and mesogenic sublayers; since the smectic order is kept with dilution (i.e., there is no significant change in the lateral order of the side groups), it can be assumed that the increase of the smectic layer thickness corresponds mainly to the increase of the polysiloxane sublayer, as already reported for other types of liquid-crystalline polymers. 18 If such, the layer thickness should increase linearly as a function of (1 -x)/x, where x is the percentage of the ferrocene units. Thus, the slope of this linear variation can be estimated to be equal to V DMS /S, where V DMS is the volume of one dimethylsiloxane unit (ca.…”