Structure and optical characteristics of poly(p-phenylenevinylene) prepared by vapor deposition polymerization

Structure and properties of p-phenylenevinylene-p-xylylene copolymers prepared by vapor-deposition polymerization

“…In the case of precursor 1, the rate of film growth is 0.8 nm/min at a sublimation temperature of 70°С; if temperature is increased to 90°С, the rate increases by a factor of almost 2 (1.7 nm/min). As is clear from the compara tive analysis, in the case of the films synthesized via pyrolysis on quartz [28], the rate of film growth is higher than the corresponding parameter for the sam ples prepared through pyrolysis on copper.…”

“…A reduction in the roughness coefficient is apparently explained by the fact that the thermal treat ment is accompanied by secondary dehydrohalogena tion; the products of the degradation reaction diffuse from the film volume through the surface, and the roughness and irregularity of the surface increase. Note that, for PPV films synthesized via pyrolysis on quartz, the roughness coefficient is 0.74 ± 0.05 and the mean square roughness is 5-10 nm [28]. These values suggest that, during thermal treatment of the films deposited via pyrolysis on quartz, modification of the surface is more pronounced and, hence, the secondary dehydrohalogenation is more intense than that for the films formed via pyrolysis on copper.…”

“…For the samples synthesized on 10 cm 2 of the copper catalyst, weight losses were smaller (8%). In the pre cursors formed via pyrolysis on quartz, the content of chlorine, as estimated via elemental and thermogravi metric analyses, was above 20% [28].…”

“…In this case, the pyrolysis of dichloro p xylene mainly involves dehydrochlorination. As was shown in [28], the concentration ratio between chloro p xylylene and p xylylene during pyrolysis on quartz is 4 : 1. The properties of the p phenylenevinylene-p xylylene copolymer prepared through the codeposition of products of pyrolysis of α, α' dichloro p xylene and [2,2] paracyclophane were investigated in [29]; as the amount of p xylylene fragments in the copolymer increases, the fluorescence spectra show a pro nounced hypsochromic shift.…”

“…p Phenylenevinylene fragments with a conjugation length of 8-12 units serve as luminophores in PPV. The transfer of excita tion from short conjugated chain fragments (stilbene and distyrylstilbene) to longer ones was observed in [28].…”