Synthesis And Phase Structure Of Supramolecular Liquid Crystalline Polymers Based On Hydrogen Bonding

A series of supramolecular polymer complexes P4VP(nCTB)x were investigated, in which dendron-like small molecules with phenolic end group(nCTB, n = 6, 10, 12, 14)were hydrogen-bonded to pyridine group of poly(4-vinylpridine)(P4VP), forming supramolecular side-chain polymers, Their phase behaviour and phase transition were studied with respect to the blending ratio of small molecules per vinylpridine unit(x),alkyl tail length(n), temperature and thermal history. Furthermore, this method was extended to the PS-b-P4VP(12CTB)x supramolecular systems. After annealed by special solvent, the multi-scale structure of the ordered orientation “structure within structure”were studied both in bulks and thin films.A series of dendron-like molecules named nCTBs(n = 6, 10, 12, 14) were reported in this work, which contain a short rod-like rigid core attached by three alkyl tails. The number of ethylene group of every alkyl tail varied from 6 to 10,12,14. We confirmed the chemical structure of small molecules and ensured the purity using the method of1 H NMR. Liquid crystal properties of the molecules were studied by POM. DSC results showed that Ti decreases when we test the longer alkyl tail molecules. With longer alkyl tails, the size of the molecules tend to smaller.Supramolecular hydrogen bonded liquid crystalline polymer complexes P4VP(nCTB)x(n = 6, 10, 12, 14) were prepared and their self-assembly structures were characterized by a combination of DSC, POM and SAXS methods. P4VP(nCTB)x could form supramolecular lamellar and hexagonal columnar(ΦH) phases dependenting on the blending ratio of nCTB per vinylpridine unit(x), alkyl tail length(n) and thermal treatment. P4VP(6CTB)x only exhibited lamellar phase. When increasing x, the phase structure of polymer complexes, for n = 10, 12, 14, were able to transform from lamellar to ΦH phase. An order to order transition from lamellar to ΦH phase appears in the heating process when the volume fraction of alkyl tails at the region of 0.56-0.58, which had been investigated and discussed.PS-b-P4VP(nCTB)x complexs were successfully prepared using solution blending and spin-coating methods. The phase structures of bulks were characterized by means of2D-SAXS and TEM, Which found the formation of hierarchical nanostructures. Thecombination of AFM and GI-SAXS measurements helped draw the conclusion that we could get the multi-scale structure of the ordered orientation “structure within structure”.Factors such as film thickness and the selected solvent could greatly influence the morphology of the final film. Limited by time, only some interesting phenomena in these systems were observed. More efforts should be put to explored the mechanism for the formation of the complex structures.