Study On Nanoporous Polymer Films

With the development of all optical network and the increase of the frequencies of the carrier wave, and also with the narrow bandwidth for modern communication technology day by day, the research for optic transmitting medium become more and more important. Nanoporous polymer films give a new idea. Through the building of the model for the relationship between its effective refractive index and porosity, we can fabricate the nanoporous polymer film with certain refractive index by controlling the porosity, and the refractive index can be fine-tuned with great precision, which will be applied in the field of waveguide components widely. So, the research is of great importance and practical value.This thesis emphasizes on the research about the relationship between the effective refractive index and porosity of the nanoporous polymer film in theory and by FDTD simulating, the process for fabricating the nanoporous polymer film using PS/PMMA through a lot of experiments, and the test of its optical performance and the analysis of its morphology. The main contents and conclusions are listed as following:Firstly, on the basis of several models for multi-phase medium, a kind of model for the effective refractive index of nanoporous polymer film made of PS, PMMA and pore, was induced. And then the relationship between the effective refractive index and porosity was analyzed.Secondly, Finite Difference Time Domain (FDTD) method was introduced simply at first, Then optical transmitting behaving was simulated in the nanoporous polymer film. According to the simulating results, its effective refractive index was computed, And it was found that the simulating results was accordance with the theoretic line.Thirdly, the process of fabricating the nanoporous polymer film using PS/PMMA was expounded, And the main causes which influence the morphology of the films were analyzed deeply, Then a perfect process procedure was concluded.Finally, Ellipsometry and atomic force microscopy(AFM) were used to characterized the film quantitatively, the effective refractive index and thickness of the films were tested by Ellipsometry, and the film morphology was observed by AFM. From that, which was found that the PS/PMMA molecular weight was main causes influencing the size of the film pore.