Polissilanos e polissilanos ramificados

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

The polysilynes (SiPh)m, the linear polysilane (SiPhMe)n and the branched polysilanes [(SiPh)m(SiPhMe)n], [(SiPh)m(SiMe2)n], [(SiEt)m(SiPh2)n] and [(Sic-hex)m(SiPh2)n], with m/n ranging from 0,50/0,50 to 1,0/0,0, were synthesized in good yields from the sodium/toluene reductive coupling of the appropriate organochlorosilanes. The materiais were characterized in relation to compositon, number average molecular weight, absorption in the ultraviolet-visible region and degree of oxidation. The photoxidation process of thin films of the different polymers by ultraviolet irradiation, was comparatively studied in relation to the characteristics of each material. These studies were performed by accompanying the changes in the films absorption in the ultraviolet-visible and mid-infrared regions. The main chemical changes during 337nm (Iaser N2) irradiation were the formation of siloxane and silanol groups with a ratio that varied from 1,4 to 3,0, indicating partial degradation of the branched structures. The degree of oxidation of the polymer films varied from 35 to 41 %, but the amount of oxygen incorporation was greater for the more branched ones, probably due to the higher concentration of SiSi bonds in those films. The changes in the index of refraction and in polymer film thickness, during the photoxidation process, were studied by light diffraction measurements and by scanning electron microscopy .A decrease in the index of refraction and a simultaneous increase in the thickness of the polymer films up to 5% of the initial values were observed. The expansion in film thickness was greater for the more branched polymers. The index of refraction and relief modulations suggest that these material are potentially interesting as optical recording materiais for the construction of optical components does not involve wet development.

ASSUNTO(S)

filmes finos refração otica

ACESSO AO ARTIGO

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