Order in polymers with biphenylyl residues in the side‐groups

Abstract

Previous papers from this laboratory') have shown that poly(4-biphenylyl acrylate)" (2a) is characterized by a smectic-like structure in the solid state and displays properties usually considered typical of highly crystalline polymers. It has also been demonstrated that the long-range smectic organization of the macromolecules of 2a takes place independent of the stereoregularity, although the smecticisotropic transition (which, for this polymer, presents all the features of a melting phenomenon) is observed at lower temperatures for isotactic samples (ca. 220 "C) than for atactic ones (ca. 270°C).Since it is known that biphenyl derivatives containing only one, reasonably small, para-substituent are not mesogenic, it is understandable that 4-biphenylyl acrylate

Synthesis, characterization and liquid crystalline properties of polyacrylates and polymethacrylates containing aryl ester pendant unit

“…Aryloxyethyl acrylates and aryl acrylates (11)(12)(13)(14)(15) were prepared by reacting acryloyl chloride with aryloxyethanols and 4-substituted phenols, respectively, in the presence of triethylamine in MEK at 0 -5°C (Scheme 2).…”

“…[1][2][3][4][5][6] The polymeric backbones of SCLCPs are primarily polyacrylates, polymethacrylates and polysiloxanes, and the mesogenic moieties are mainly derived from substituted benzoic acid, aromatic schiff bases, substituted biphenols, aromatic azo or azoxy compounds. Poly(4-acryloyloxybenzoic acid) and poly(4-methacryloyloxybenzoic acid), 10 poly(4-biphenyl acrylate), 11,12 and poly(4-cyclohexylphenyl acrylate), 13 are the notable SCLC polymers which exhibit mesophase properties without the presence of any flexible spacer between the polymer backbone and the pendant mesogen unit. The spacer decouples the mesogenic side groups from the backbone and renders the mesogens to order anisotropically to a first approximation.…”

The recent developments of thermotropic liquid crystalline polymers

“…These postulates are generally found to be correct, but contradictory results have been seen. For instance, Bresci et al (132) found that the incorporation of CH2 and (CH2J20 into poly { 1 -[ 6-( 4-biphenyly1oxy)-hexyloxycarbonyl]ethylene) results in the destruction of LC order. This strange result certainly implies that the current explanation needs modification.…”

Structural variations of liquid crystalline polymer macromolecules. Review

“…In this paper only few examples of the liquid crystalline comb-like polymers will be presented. BRESCI et al [98] investigated the influence of the spacer length between main chain and biphenyl group in the polymer having the structure shown in Scheme 22 on the ability of mesophase formation. If the biphenyl unit was directly connected with the oxygen of the ester group the polymer formed a smectic mesophase.…”