Discrete Block-polymer With Different Junction:Synthesis And Self-assembly

Block copolymers self-assembly can construct complex nanostructures with various properties which provides potential applications in many fields,including photolithography,next-generation electronic devices and drug loading.Classical theory holds that self-assembly process mainly depended on three parameters which are the volume fractions of each block,the total degree of polymerization and Flory-Huggins parameter.Recent studies show that topological structure,junction chemistry and molecular weight distribution have significant influence on the formation of nanostructure.During Self-Assembly process,interface is an important component.The interface area is the result of entropy and surface free energy,illustrating the stability of ordered phases.The variation of self-assembly parameters can tune self-assembly process which reflecting in the interface,while the changing of interface also influences self-assembly process.Eliminating the inherent defects of polymers,(molecular weight distribution,uncertain molar ratio and component),a series of precise macromolecules with different junction which have variation of volumes or interactions are used to adjust interface parameters quantitatively.Using iterative growth strategy,a series of discrete Oligo Lactic Acid(o LA)and Oligo Dimethylsiloxane(o DMS)were synthesized which is the reactants of Liner and X-shape precise macromoleculesResulting a strong separation strength when using short connection to construct X-shape macromolecules,data indicate that the order-disorder transition temperature increases significantly form 50 ℃ to 90 ℃.Comparing with linear and Y-shape molecules with the same volume fraction,the phase boundary of the X-type molecular phase diagram may be shifted.Adding Polyhedral Oligomeric Silsesquioxane(VPOSS)at the junction,which change the chemical composition,promote self-assembly.The designed molecules can simultaneously adjust the volume of connection points,chemical composition and intermolecular interaction.Preliminary results show the potential multi-factor promotion of self-assembly,which need further study.This work serves as a unique platform for revealing the influence of interface properties on the self-assembly process.