Depth-profiles of structure in single- and multilayered commercial polymerfilms using grazing-incidence X-ray diffraction

Grazing-incidence X-ray diffraction is used to analyze the variation in str uctural features-such as crystalline index and crystallite size perfection (CI and CSP)-with depth in several commercially relevant mono- and multi-la yer polymer films. The CI and CSP at the casting roll surface of a melt-cas t and biaxially oriented nylon 6 (N6) him is the same as in the bulk, but t he air-exposed surface has lower CI and CSP than the bulk. These difference s are attributed to the influence of the initial crystallization behavior a t the two surfaces (roll-surface poorly ordered than the air-surface) on th e eventual crystallinities observed after drawing. In a bilayer laminate of poly(chlorotrifluoro ethylene) (PCTFE), and poly(ethylene-ethyl acrylate) (EEA), the CI is lower but the CSP of PCTFE appears to be higher at the int erface between PCTFE and EEA. The technique was able to find differences in the PE unit cell volume within the PE layer at the air/PE and PE/N6 interf ace in a three-layer film (PE/N6/PE). The method was also used to monitor t he variation in preferred orientation with depth in the aluminum layer depo sited on polymer films in a multilayered structure, as well as to examine t he thin surface coatings. (C) 1999 Elsevier Science Ltd. All rights reserve d.