Synthesis And Self-Assembly Of Containing Ester Or Carboxyl Series Of Oligomers

During the last decade, π-conjugated molecules have attracted a great deal of attention due to their outstanding self-assembling properties and applications in the field of biomimetic materials, medical technologies, supramolecular nano-reactors, nano-sensors and transport membranes, and so on. Precise control of the π-conjugated molecular nano-structures is achieved by tuning the molecular parameters through non-covalent molecular interactions, such as hydrophobic and hydrophilic effects, electrostatic interaction, π-π stacking, hydrogen bonding, and micro-phase separation.In this thesis, We designed and synthesized three series rod-coil block oligomer containing ester or carboxyl units, and the molecular structures were characterized by ’H-NMR and MALDI-TOF-MS. Their self-assembling morphology was studied in the bulk and aqueous solutions by using differential scanning calorimetry(DSC), thermal optical polarized microscopy (POM), smallangle X-ray scattering (SAXS), ultraviolet-visible and fluorescence spectroscopy (UV-vis and FL, respectively), Dynamic Light Scattering (DLS), circular dichroism (CD), transmission electron microscopy (TEM).First of all, we synthesized a series of rod-coil molecules which incorporate lateral ester groups in the middle of the rod segment, and studied the self-assembling morphology in the bulk. Subsequently, we investigated the self-assembling morphology on the change of aqueous concentration; Secondly, we synthesized a series of rod-coil molecules which incorporate lateral carboxyl groups in the middle of the rod segment. As a result of the existence of carboxyl, the hydrogen bonds are formed when the self-assembly behavior is studied in the bulk. Finally, we introduce the ester to molecules, and studied the self-assembly behavior of molecules in the bulk and aqueous solution. The results showed that steric hindrance is existed between molecules. It’s negative to self-assembly of molecules when incorporate lateral ester groups in the middle of the rod segment. The experimental results implied that although hydrogen bonds enhancing the molecular interaction and inducing molecular arrangement by forming supramolecular nanostructures, the directional nature of hydrogen bonding can reduce molecular interactions, e.g. pi-pi stacking.