Substitution effects on the liquid crystalline properties of D,L-xylitol amphiphiles

In this article we describe the self-assembling properties of alkyl substituted xylitols in relation to both thermotropic and lyotropic liquid crystalline mesophases. Three series of substituted xylitols were prepared where aliphatic chains of varying length were attached to a xylitol moiety via ether, thioether and ester linking groups. The thermotropic properties were investigated by thermal polarized light microscopy and differential scanning calorimetry, and evaluated as a function of chain length and linking group. The lyotropic phase behaviour was investigated via the addition of water to each material at room temperature. The efficiency for forming thermotropic phases was found to be reversed for the lyotropic phases in respect of the three series, i.e. as a function of the linking unit.