Unique block molecules based on glycerol skeleton as C-3 building blocks for liquid crystals formation by self-assembly and their future potential for the 'nano-chemistry'

摘要

Studies on design of liquid crystalline block molecules with non-conventional mesophase morphoplogies have been proposed by Tschierske and co-workers.These block molecules have a rigid core,a lateral substituent,and an alkyl chain segmenting blocks from each other.Related to this,diglyceryl alkyl ethers found by us have glycerol as a rigid core,a lateral substituent,and an alkyl chain similar to the Tschierske design.These two cases are compared with each other with regard to the relationship between the molecualr structure and the liquid crystalline morphologies and other properties.Recently,new soft materials suitable for liquid crystals exhibiting self-assembly of phase-segregated structures have been designed.Typical examples of such "block" molecules containing glycerol having a C-3 building block include:(i) undecyl-glycerylether-modified siloxane derivatives with a siloxane segment as the rigid core and alkyl chains with 2,3-dihydroxypropoxy group as a hydorphilic group at a lateral or terminal position of the siloxane segment;(ii)novel hyper branched dendrimers forming the basis of polyglycerol nanopcapsules with a core-shell molecular architecture;(iii) carbon nanotubes based on cyclodextrins(CDs);(iv)polymerizable amphiphilic diacetylene-containing phospholipids suitable for construction of functional nanocomposites.This is done by self-assembly and polymerization of diacetylene creating a "block molecular structure"with a polyacetylene chain as a rigid core segment,the lipid headgroups as the hydrophilic segment,and terminal flexible alkyl chains.On the basis of these results,future potential of block molecules as a soft building material for liquid crystalline structures was discussed.