In-situ Synchrotron Small Angle X-ray Scattering Research On The Self-assembly Behavior Of Block Copolymers

Block copolymer self-assembly has attracted considerable attention for many decades because it can yield a series of ordered nanostructure morphologies which have potential values in industrial application and theoretical research.Now,the foucuses of research are on the mechanism of self-assembly,model simulation and the acquisition of a wide range of block copolymers nanostructure including spheres,cylinders,bicontinous structures,lamelle and vesicles prepared by micelles or films.As traditional characterization techniques such as Transmission electron microscope(TEM)can not provide an accurate scene of the process of block copolymer in bulk,soulution or film,we need some other techniques to obtain complementary information.The aim of this thesis is to develop the experimental techniques on the characterization of the process of block copolymer self-assembly in different conditions based on small angle x-ray scattering beamline in Shanghai Synchrotron Radiation Facility.The main works were shown as follows:In-situ research on the self-assembly behaviors of block copolymer in bulk during the thermal annealing was carried out.We characterized two kinds of process of block copolymers self-assembly based on the techinique of Small Angle X-ray Scattering(SAXS).Through the analysis of scattering data,we quantitatively obtain the transition of block copolymer during thermal annealing and the detail of the phase transition.The result shows that during the increasing of temperature,the size of block copolymer nanostructure increases gradually,and during the phase transition,the rod-like structure turn into spheres structure.In addition,the holes in the nanostructure decrease gradually and disappear in the last.The results verify the theoretical phase diagram of block copolymer and obtain the morphologies during the phase transition.The self-assembly behaviors of block copolymer in solvent and thermo response were investigeted.We characterized the morphologies of block copolymer micelles dissolved in different solvents via TEM and SAXS techniques.During the increasing of water content in the solution,the size of block copolymer micelles increases gradually.And during the characterization of in-situ SAXS thermal experiment,we found the structure of double peaks.As the temperature increases,the two peaks enhance and disappear respectively,and the velocity is equal.It indicates there's two kinds of particles exiting in the solution,and transfer to each other during the change of temperature.The process and mechanism of self-assembly of the block copolymer PS-b-PAA thin films.We obtained the block copolymer thin films through the method of layer-bylayer self-assembly.Via the techniques of Atomic Force Microscope(AFM)and Grazing Incidence Small Angle X-ray Scattering(GISAXS),we characterized the nanostructure of block copolymer thin films and the influence of selective solvent and number of layers on the self-assembly of block copolymer thin films.As the content of organic solvent increases,the nanostructure in the films turns from sphere structure to rod-like structure and lamellae structure.And during the increasing of the number of layers,the structure grows from simple monomers to nanoparticles and turns to islandlike structure at last.Above all,the main work of this thesis is to describe the process of block copolymer in different conditions.It can help us understand the process of selfassembly of block copolymers and develop the application of SAXS techinique on the characterization of block copolymers.