Abstract
In the thesis, we studied residual stresses and electric field induced patterns on polymer thin films as well as annealing behavior of polymeric materials after irradiation. In the first part, we built a Parylene C/Si bilayer cantilever structure. The Parylene C thin films were continous and flat on the top of cantilevers. Due to the mismatch of thermal expansion in this system, cantilevers curved and bent towards up. We inferred that the deposition temperature was 73 oC by observing the curvature variation. Moreover, the residual stress distribution was linear in both layers and discontinued on the interface. In the second part, we studied the generation kinetics of color centers in gamma ray irradiated poly(4-methyl-1 pentene) (PMP). The transmittance loss in irradiated PMP with increasing gamma ray dose and annealing temperature, and present bathochromic shift in UV/ Vis spectra. The absorptance data were found in good agreement with the first order reaction. On the other hand, the color centers of polycarbonate (PC) will annihilated at elevated temperature after irradiated. The measured absorptance data followed first order mechanism, and the absorptance was nonlinearly proportional to the concentration of annealable color centers. In the third part, we discussed the radicals annihilation of gamma ray irradiated poly(methyl methacrylate) (PMMA) and Poly(2-hydroxyethyl methacrylate) (PHEMA) at elevated temeratures. We inferred that both PMMA and PHEMA had three different radicals at least. The radicals Ra and Rb followed second order process for PMMA and PHEMA. Rc of PMMA in a short time period followed a first order decay and turned into second order in the long term. Rc of PHEMA followed second order kinetics at longer times. For a given dose and annealing temperature, the concentration of each radical decreased with time. In the last part, we investigated electric field-induced periodical pillar patterns via thin film instability of PC and PMMA. The pillar patterns grew at the initial stage of experiments for both polymers. Thepillars were smaller and less dense for thinner film, and increasing with annealing time. The growth rate was decreased gratually and steadied after forty miniutes. The process of growth were in good agreement with fitted curves. Comparing steadied patterns at different annealing temperatures,diameters and space between pillars were largerat higher annealing temperature. Combining these two factors, we concluded that the periodicity was increasing with increased annealing temperature for the films with the same thickness; the periodicity was increasing with increased film thickness for the same annealing tempaerature.