Tensão mecanica residual em filmes de polimeros depositados em plasma de acetileno

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

This thesis describes a study on the residual mechanical stress, s , of polymer films prepared in dc and rf glow discharge plasmas of acetylene. In the first part of the work we report the behavior of s as a function of film thickness and discharge parameters (acetylene pressure and power applied to the discharge). In the second part we study the time evolution of the stress in various ambients: air, oxygen, nitrogen and vacuum. Measurements were carried out by the bending method, using a He-Ne laser. The polymer films were deposited on thin soda lime glass substrates. After deposition the specimens were mounted in a chamber that could be evacuated or filled with air, oxygen and nitrogen. A steady rise in the stress during time periods of several hours following film deposition was observed in most of the samples studied. Stress increments of more than one order of magnitude were detected in some of the films upon exposure to air. Pronouced stress increments were also observed during exposure to oxygen. Rises in the stress were detected even in a vacuum ambient. Nitrogen exposure was found to have little effect on the stress. The effect of the moisture content of the air on the stress was also examined. The evolution of the stress was found to depend also on the film preparation conditions. The results strongly suggest that post plasma reactions involving active chemical species trapped in the film during deposition play an important role in the development of the stress

ASSUNTO(S)

polimeros e polimerização

ACESSO AO ARTIGO

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