Synthesis, aqueous solution behaviour and amphotropic liquid crystalline properties of glycerol based bolaamphiphiles

Abstract

Two new homologous series of new single-chain diether bolaamphiphiles with glycerol headgroups have been synthesized: 1,1′-O-(alkane-α,ω-diyl)bis(rac-glycerol), 1, and 2,2′-O-(alkane-α,ω-diyl)bis(glycerol), 2, bearing 10 to 22 methylene groups (n). They were studied by surface tension measurements, microscopies and X-ray diffraction patterns. From the set of molecules 1, we have shown the formation of amphotropic liquid crystals. A lamellar L_α phase has been identified at high temperature while a more complex second phase was detected at low temperature. In this case, the texture is also characteristic of a lamellar phase (L_β) and its organization was found to be monoclinic by X-ray analysis. Furthermore, these compounds led to multilamellar vesicles in aqueous solution (liposomes) with the flexibility depending on temperature. Synthèses, comportement en phase aqueuse, et proprie′te′s cristal liquide de bolaamphiphiles à tête glyce′rol. Deux se′ries homologues de mole′cules bolaformes monocate′naires à tête glyce′rol ont e′te′ synthe′tise′es: les 1,1′-O-(alkane-α,ω-diyl)bis(rac-glycerol), 1, et les 2,2′-O-(alkane-α,ω-diyl)bis(glycerol), 2, comportant de 10 à 22 groupes me′thylène. Ils ont ensuite e′te′ e′tudie′s par tensiome′trie, microscopies et diffraction aux rayons X. Dans le cas des mole′cules 1, nous avons observe′ la formation de phases cristal liquide. Une phase lamellaire L_α a e′te′ identifie′e à haute tempe′rature tandis qu'à basse tempe′rature, une phase L_β est de′tecte′e. De plus, les compose′s conduisent à des ve′sicules multilamellaires en solution aqueuse dont la flexibilite′ de′pend de la tempe′rature.