Supramolecular Side-Chain Liquid Crystalline Polymers with Various Kinked Pendant Groups

Abstract

Supramolecular side-chain liquid crystalline polymers with various kinked pendant groups are constructed from positional isomers of proton acceptor monomers and donor polymers (with different molecular weights) through hydrogen bonding. Monomer−monomer complexes of similar structures are built to compare the influence of the proton donors bound to the polymer backbones. Due to the bending effects introduced by the positional isomers, we are able to tune the molecular shape and thus to modify the mesogenic properties. New liquid crystalline properties are introduced by the kinked molecular geometry, and their kinked architecture is supported by the quantum mechanical calculations, the powder X-ray diffraction (XRD) patterns, and the deviation temperatures (ΔT). Mesogenic properties of monomer−polymer complexes have similar trends as those of monomer−monomer complexes. Compared with analogous hydrogen-bonded (H-bonded) monomer−monomer complexes, higher isotropization temperatures and broader ranges of mesogenic phases (e.g., SA phase) are observed in the kinked supramolecular polymers. Significantly, H-bonded positional isomerism leads to dissimilar structures and properties of supramolecular side-chain liquid crystalline polymers.

Mesophase behaviour of azobenzene-based angular supramolecular hydrogen-bonded liquid crystals

“…[27][28][29][30][31][32][33] Alteration of the binding sites of the supramolecules is simple and effective way to change the shape of SMHBLCs [34][35][36][37] in order to design new materials with new mesomorphic properties. Herein, we extend our systematic study to investigate the effect of introducing additional azobenzene unit to the angular supramolecular complexes previously reported by us [36] through hydrogen-bond formation between 4-alkoxyphenylazo benzoic acids (In) [38,39] as proton donors and 4-(3ʹ-pyridylazo)-4ʹʹ-alkoxybenzoates (IIm) as proton acceptors (see Figure 1).…”

Hydrogen-bond induced side-chain liquid crystalline polymers based on nicotinic acid derivatives

“…The most common rigid cores in supramolecular LCs are linear structures with para-substituted aromatic rings Hbonded to pyridyl and carboxylic acid moieties. Nevertheless, some supramolecular LCs with nonlinear structures has been reported to display interesting mesomorphic properties [24,25]. Herein, the spacer-dependent H-bond-induced mesophase formation of nicotinic acid derivatives was studied.…”

C60-containing polymer complexes: Complexation between multifunctional 1-(4-methyl)piperazinyl-fullerene orN-[(2-piperidyl)ethyl]aminofullerene and proton-donating polymers

“…Recently, the use of specific intermolecular interactions such as hydrogen-bonding and ionic interactions to prepare self-organized materials such as liquid crystalline polymers has attracted considerable interest [3][4][5][6][7][8] . Similarly, interpolymer complexes obtained through strong intermolecular interactions have also been extensively studied [9][10][11][12][13][14][15][16] .…”