Research On Micro-structure Of Self-assembly Films By Sychrotron Radiation Grazing Incidence X-ray Scattering

Grazing Incidence X-ray Scattering (GIXS) was an advanced tool forcharacterizing structure of films. It was nondestructive to the sample during test, andit could provide structure information over large macroscopic region. As combinedwith synchrotron radiation facility, In-situ GIXS technique could be used to observestructure variation during growth or reaction process. Therefore, the GIXS techniquehas received considerable attention during the past decade. The aim of this thesis is todevelop and improve experimental methods based on small angle scattering beamlinein Shanghai Synchrotron Radiation Facility (SSRF). And we used this technique toprobe micro-structure of the self-assembly mesoporous film and polyelectrolytemultilayer. It was benefit to the development of GIXS technique for films. The mainworks were shown as follow:1. Developing and improving experiment methods of GIXS technique. Throughanalyzing of theory model and experimental result, calibrating equation wasdeveloped to revise scattering angle for wide angle scattering experiment. Thecalibrating process was simplified comparing to previous method. In addition, thefirst temperature controlling device was designed for in-situ GIXS experiment onSmall Angle X-ray Scattering Beamline BL16B. Therefore, the structureevolution followed with temperature could be observed under vacuum or inertatmosphere. In addition, we developed a data treatment platform which includesintact data processing modules. The platform could solve problem ofincompatible format for data analyzing software. Moreover, mass data producedduring in-situ experiment could be processed efficiently with batch processingmodule.2. Research on structure of self-assembly mesoporous film and the process ofremoving template. A general model was developed to estimate the orderingdegree of mesoporous. It could provide information on the size distribution, orientation, position distortion of mesochannels, and so on. Three kind ofmesoporous films were analyzed by the developed model. The results indicatedthat the main structure discrepancy was showed in two aspects: the distance ofposition deviation from ideal lattice and length distribution of mesochannels. Inaddition, we observed structure evolution of mesoporous film in the process ofremoving template with time resolution of several seconds. During the process,the mesochannels firstly swell followed by shrinkage in the vertical direction.Then Local structure defect was produced in the process. As most of templateswas removed, the local defect grown into regional structure disorder. Then theordering degree of the mesoporous film was decreased. And the temperatureincreasing rate for template removing process is closely relation with thedeformation amount of mesochannels. The results are meaningful to improve thepreparing technique of mesoporous films.3. Research on micro-structure of polyelectrolyte multilayer and growth mechanism.This study characterized the surface structure of layer-by-layer self-assemblychitosan/poly(-glutamic acid) multilayers through Grazing-incidenceSmall-angle X-ray scattering (GISAXS), X-ray Reflectivity (XRR), and AtomicForce Microscopy (AFM). A weakly long-period ordered structure along in-planedirection was firstly observed in the polyelectrolyte multilayer by GISAXStechnique. This structure can be attributed to nanodroplets formed bypolyelectrolyte molecules orderly arranged along the free surface of the films.This ordered structure gradually disappeared with increasing bilayer numberbecause of the complex merging behavior of nanodroplets into large islands.Furthermore, resonant diffuse scattering became evident in the GISAXS patternsas the number of bilayers in the polyelectrolyte multilayer was increased. Thiscould provide experimental support for the three zone model for PEM films.Notably, the lateral cutoff length of resonant diffuse scattering for thesepolyelectrolyte films was comparable with the long-period value of the ordered nanodroplets in the polyelectrolyte multilayer. Therefore, the nanodroplets couldbe considered as basic transmission unit for structure propagation from innerinterface to the film surface. It suggest that the surface structure with length scalelarger than the size of nanodroplets was partially complicated from interfacestructure near substrate, but surface structure smaller than the cutoff length wasmainly depended on the conformation of nanodroplets. Based on the previousstructure model, GISAXS patterns were simulated to support the analysis results.In addition, this thesis studied structure variation during the heat treatmentprocess through in-situ GISAXS technique. The results could provide guidancefor controlling micro-structure of polyelectrolyte multilayers by heat treatmentmethod.The thesis was started with development of experimental methods for GIXS technique.Then we used the GIXS technique to study two kinds of self-assembly films. Severalcritical issues were solved in our study. It is meaningful for development of studyingfilm materials with GIXS technique.