Self-assembly Of Fullerene Block Molecules Based On Hydrogen Bonding And π-π Interactions

Fullerene C60 liquid crystal materials have excellent photoelectric properties from C60 and the field responsive properties from liquid crystals.They are a class of organic optoelectronic functional materials with broad application prospects,but there are problems such as insufficient phases and low clear point temperature.In view of the above problems,a class of fullerene block molecules containing amide bonds were designed and synthesized in this thesis.The introduction of hydrogen bond supramolecular interactions from amide groups leads to the self-assembly of block molecules to form stable new fullerene supramolecular structures and corresponding liquid crystal phases,thus improves the clear point temperature.The research contents are listed below:1.A series of flexible spacer blocks(m=6)fullerene block molecules containing amide bond T-C-CONH-C6-C60(n=4,6,8,10,12),with different alkyl tail chain lengths of were synthesized,its chemical structure was proved by 1H NMR,MALDI-TOF MS,FT-IR.The phase structure was characterized by TGA,DSC,POM,SAXS,TEM,SAED,and AFM.The result shows that when the alkyl tail chain is short(n=4,6),is a layered phase supramolecular liquid crystal phase,and the fullerene C60 crystals in the layer form a two-dimensional crystal arranged in a square arrangement,and the periphery is an amorphous region composed of flexible alkyl chains;when the alkyl tail chain grows(n=8)with two liquid crystal phases,it is a rectangular columnar(ColR)supramolecular liquid crystal phase in the low temperature phase and is a layered supramolecular liquid crystal phase in the high temperature;when the alkyl tail chain further grows(n=10,12),only hexagonal columnar phases of supramolecular liquid crystals(ColH)are formed.The above liquid crystal phase is formed by π-πinteraction between C60S,hydrogen bond,and microphase separation of C60S and alkyl tail chain.2.A series of flexible spacer blocks(m=8)fullerene block molecules containing amide bond T-Cn-CONH-C6-C60(n = 4,6,8,10,12),with different alkyl tail chain lengths of were synthesized,its chemical structure was proved by IH NMR,MALDI-TOF MS,FT-IR.The phases structure and thermal behavior in this series of block molecules with longer flexible spacers were characterized by TGA,DSC.POM,and SAXS.The result shows that when the tail chain length is short(n=4,6,8,10),the block molecules form a two-dimensional crystal nanosheet supramolecular liquid crystal layered phase.A two-dimensional crystal nanosheet contains four layers of C60s in T-C4-CONH-C8-C60 block molecule.A two-dimensional crystal nanosheet contains three layers of C60s in T-Cn-CONH-Cs-C60(n=6,8,10)molecules.When the tail chain further grows(n=12),hexagonal columnar supramolecular liquid crystal phase(ColH)is formed.The above structural shows the self-assembly behavior of fullerene block molecules and their supramolecular liquid crystal structure can be regulated by the length of hydrogen bond and alkyl tail chains.