Self-assembly Of Completely Hydrophobic Linear Polymers And Magnetic Cluster Based Complexes

Nanosized objects of polymers have shown various potential applications in the fields of material,biomedical science and catalysis.Conventionally,nanosized spheres,cylinders,bilayers,and others can be achieved by self-assembling amphiphilic small molecules or block copolymers in selective solvents.However,star polymers exhibit some remarkable characteristics and properties that can't obtain in simple linear polymers,for example,it has topologically nanostructures.Hence,they constitute a unique class of technologically important nanomaterials that have been utilized for many applications in life science and nanotechnologies.In the first portion,we reported the self-assembly of totally hydrophobic linear homopolymers with stepwise increasing stiffness such as polystyrene,polyphenylacetylene,and poly(3-hexyl thiophene)leads to the formation of free-standing sheets with thicknesses of several nanometers and planar sizes up to micrometric ranges in solvents with moderately weakening quality,namely,in the toluene/methanol mixture solvents with methanol volume ratios of 43%,50%,and 67%.In the case of polyphenylacetylene,further weakening solvent quality with methanol volume contents of 75% and 90% reveals the presence of coexistence of free-standing sheets with hollow nanostructures or a total hollow structure phase in the latter solvent condition.The coexisting behavior is a typical intermediate stage for a morphological transition from sheetto vesiclelike nanoassemblies and thus provides deeper mechanistic insight for their formation and evolution.The difference is that polystyrene forms solid spheres,but for poly(3-hexyl thiophene),ill-defined aggregates appear together with free-standing sheets under these highly worsening solvent conditions.The higher order nanostructures such as free-standing sheets and vesiclelike nanoassemblies are generated by totally hydrophobic linear homopolymers in organic solvents with worsening quality,which is completely different from the well-known paradigm for conventional micellelike nanoobjects fabricated by amphiphiles in selective solvents.We give on a further research on the self-assembled of completely hydrophobic linear polymers in chloroform/methanol mixture solvents and chloroform/hexane mixture solvents and they can also form hollow structure.Furthermore,these sheet-and vesiclelike nanostructures are in a form of precipitates,which is in sharp contrast to conventional insight into the precipitate process of linear homopolymers via an intermediate state of spherical coacervate droplets in solvents with weakened quality.In this connection,the present finding has extended the knowledge of polymeric self-assembly and colloidal chemistry.In the second portion,we synthesize two high-nuclearity lanthanide-transition metal cluster based complexes with different polyethyleneglycol(PEG)units via electrostatic interaction in aqueous solutions.They can form vesicles in dichloromethane but form free-standing sheets in the methanol/water mixture solvents.Both the two metal cluster based complexes maintain magnetic property compare with the pure metal cluster.