Assembly And Structures Of Novel Supramolecular Functional Polymers Based On Hydrogen-bond

Supramolecular polymers are polymers based on monomeric units held together via directional and reversible secondary interactions, resulting in polymeric properties in dilute and concentrated solutions, as well as in the bulk. Because the energy of non-covalent bond and lifetime of the chain can be controlled by temperature or other environmental conditions, with dynamic reversibility, the characteristic of such dynamic bonding system such as viscosity, chain length, composition can be controlled, possessing incomparable advantages in contrary to conventional polymers. Multihydrogen-bonding polymers make up to the weak stability of non-convalent bonding polymers, has attracted many investigators'attention. In this dissertation, we adopted a strategy, introducing the bismelamine with functional blocks such as perylene bisimide and naphthalene bisimide to obtain novel monomers, and gave an emphasis to the exploration of ways and means to prepare functional supramolecular polymers with orderly structures, then further studied their characteristics.Nine new assembly units were synthesized: S1, S2, S3, S4, S5, S6, S7, S8, S9. Their molecular structures were confirmed by IR and 1HNMR , and the conditions of synthesis were discussed.Considering the structures of assembly unit, changing preparation conditions, solvents, concentration of monomers and so on, the structures of S1·S2,S1·S3,S1·S4,S1·S5 under different conditions were investigated. SEM and TEM images indicated that microns or even mm-class rodlike regular supramolecular micro- structure could be obtained under the larger concentration of assembly units in CH2Cl2. The effect of time on the micro-structure of S1·S4,S1·S5 was immense. When assembly time was short, gel structures were formed. While time was long enough, rigid one-dimension micro-structures were formed. Crossed polarizers images indicated that S1·S2,S1·S3,S1·S4,S1·S5 aggregations were birefringent. Aggregations'structures were related to the structures of assembly units. These orderly aggregations structures of supramolecular polymers contribute to apply in the organic optoelectronic devices widely. Compared to the ~1HNMR spectra of S1, the signals of the imidic protons underwent a downfield shift in the 1HNMR spectras of S1·S2,S1·S3,S1·S4,S1·S5. Compared to the IR spectra of S1, the wavenumbers of C=O stretching vibration diminished in the IR spectras of S1·S2,S1·S3,S1·S4,S1·S5. These results indicated that hydrogen bond was the main driving force to build orderly supramolecular structures. The spectrum properties of aggregations were investigated through fluorescence spectras and UV-Vis absorption spectras. After the aggragations formed, fluorescence emission intensity decreased. These spectra changes were mainly caused by intermolecular charge transfer arosed by hydrogen bond. These results provide an important scientific basis to the study on further develop functional supramolecular polymers.