Polymer Nanocomposites Based On Platinum(?)complexes: Synthesis,Self-assembly And Photophysical Properties

Square-planar platinum(?)complexes exhibit intriguing spectroscopic and luminescent properties.They tended to form Pt···Pt and/or ?-? stacking interactions,leading to controllable phosphorescence in the aggregate states.Additionally,block copolymers can self-assemble to generate hierarchical nanostructures in selective solvents,typically including spherical and cylindrical micelles and bilayered vesicles.All of these nanostructures have resulted in various potential applications,such as patterning fabrication,drug delivery,fluorescence sensors and nanoreactors.This dissertation can be divided into two parts:In the first part,Polystyrenes have been synthesized with terminal groups of luminescence square-planar platinum(?)complexes,which can be conceptually regarded as plane-coil diblock copolymers.They can self-assemble into spherical micelles with a core of polystyrenes and a corona of planar platinum(?)complexes in the chloroform/methanol mixture solvents,while free-standing bilayered sheets form in the toluene/methanol mixture solvents.With increasing methanol content in the latter case,where the solvent quality was highly deteriorated for polystyrene blocks,the sheetlike nanostructures are readily transformed into spherical micelles.Pt···Pt and/or ?-? stacking interactions between the planar platinum(?)blocks contributed significantly to these aggregates' morphologies and their evolutions,leading to remarkable luminescence enhancements.This work represents a novel approach to design and synthesizes luminescence platinum(?)plane-coil diblock copolymers,in which the planar platinum(?)complexes are,for the first time,regarded as an individual block for the creation of block copolymers and micellelike aggregates in solution.In the second part,we investigate the self-assembled process of the wormlike micelles with respect to the influence of solvent quality in the toluene/methanol mixture solvents.When the methanol volume ratios are 33%,50%,and 67%,unilamellar free standing sheets are achieved,in which the wormlike micelles snap off to form starlike micelles together with a few short worms.When the methanol volume content increases to 75%,freestanding sheets show a coexisting behavior together with vesiclelike nanostructures,which is directly related to mechanistic insights regarding a morphological transition from sheet to vesiclelike nanoassemblies.Further increasing methanol content to 90% leads to a pure phase of unilamellar vesiclelike nanostructures.In all of these aggregates,short worms and starlike micelles still hold their core-shell structures.The outer coronas are highly contracted in both sheet-and vesiclelike nanoassemblies,while the coronal chains between the ionic cores show up complete interpenetration.The present results are challenging the conventional paradigm of amphiphilic self-assembly of surfactants and block copolymers in selective solvents,where they form bilayered nanostructures and during their morphological transitions from micellar to vesicular,the amphiphilic(macro)molecules are required universally to be rearranged.