The synthesis of the two monomers M1 and M2 and a series of new side-chain cholesteric liquid crystalline elastomers P2-P8 is presented. The chemical structures of the monomers and elastomers obtained were confirmed by FTIR or 1H NMR spectroscopy. The cross-link density of the elastomers was determined by swelling experiments. The mesomorphic properties were investigated by differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), polarizing optical microscopy (POM), and X-ray diffraction (XRD) measurements. Monomer M1 showed a cholesteric phase, and M2 revealed smectic and nematic phases. The effect of the cross-link density on the phase behavior of P2-P8 is discussed. Elastomers P2-P6 containing less than 12mol % of the cross-linking units displayed elasticity, reversible liquid crystalline phase transition, wide mesophase temperature ranges, and high thermal stability. Elastomer P7 displayed stress-induced birefringence, and P8 showed only elasticity with no other texture. Experimental results demonstrated that the glass transition temperatures increased, and the isotropization temperatures and the mesophase temperature ranges of P2-P6 decreased with increasing cross-link density.

A series of ionic liquid-crystalline (LC) elastomers were synthesized by using chemical crosslinking agents containing sulfonic acid groups, which were siloxane-based materials. A ionic divinyl monomer 2,2¢-(1,2-ethenediyl)bis[5-[(4-undecenoyloxy)phenyl]azo]benzenesulfonic acid was used as chemical cross-linking agent. Cholest-5-en-3-ol(3β)-10-undecenoate was synthesized as a liquid-crystalline monomer. The effective cross-link density of the ionic elastomers was determined by swelling experiments in organic/buffer mixtures. Their liquid-crystalline properties were characterized by DSC, POM, and SAXS. A proposed multilayer buildup containing LC segment structure and ionic cross-linking lamellar structure separated by siloxane chains was given. The ion aggregated in domains forces the siloxane chains to fold and form an irregular lamellar structure. The ionic cluster lamellae may be tangled with the rigid mesogenic groups of LC segments to form multiple blocks. Liquid-crystal mesophase region of the polymers become narrow with increasing ionic cross-linking content.

Liquid crystalline polymers containing sodium sulfonate groups pendant to the polymer backbone were synthesized by an interfacial condensation reaction of brilliant yellow, a sulfonate-containing monomer, with 4,4'-dihydroxy-a,a'-dimethyl benzalazine and a 50/50 mixture of sebacoyl and dodecanedioyl dichlorides. Polymers containing up to ca. 4mol% brilliant yellow were characterized by elemental analysis and ultraviolet spectroscopy. The polymers were thermally stable to about 300℃, and they exhibited a broad nematic mesophase region of 70-100℃. The solution viscosity behavior in chloroform suggested that intramolecular associations of the sulfonate groups occurred at low polymer concentrations and internolecular associations predominated at higher concentrations.

A novel side-chain, liquid-crystalline ionomer (SLCI) with a poly(methyl hydrosiloxane) main chain and side chains containing sulfonic acid groups was used in blends of polyamide-1010 (PA1010) and polypropylene (PP) as a compatibilizer. The morphological structure, thermal behavior, and liquid-crystalline properties of the blends were investigated by Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. The morphological structure of the interface of the blends containing SLCI was improved with respect to the blend without SLCI. The compatibilization effect of greater than 8wt % SLCI for the two phases, PA1010 and PP, was better than the effects of other SLCI contents in the blends.

The synthesis of new chiral smectic A (SA) side-chain liquid crystalline polysiloxanes (LCPs) and ionomers (LCIs) containing 4-allyloxy-benzoyl-4-(S-2-ethylhexanoyl) p-benzenediol bisate (ABB) as mesogenic units and 4-[[4-(2-propenyloxy)phenyl]azo]benzenesulfonic acid (AABS) as nonmesogenic units is presented. The chemical structures of the monomers and polymers are confirmed by FTIR spectroscopy or 1H-NMR. Differential scanning calorimetry (DSC), optical polarizing microscopy, and X-ray diffraction measurements reveal that all the polymers PI-PIV and ionomers PV-PVI exhibit SA texture. The results seem to demonstrate that the tendency toward the SA-phase region increases with increasing sulfonic acid concentration, and the thermal stability of the SA phase is determined by the flexibility of the polymer backbones and the interactions of sulfonic acid groups.