Rutherford backscattering spectrometry and computer simulation for the in-depth analysis of chemically modified poly(vinylidene fluoride)

The alkaline treatment of poly(vinylidene fluoride) (PVdF), in the presence of phase transfer catalysts (PTCs) has been investigated. Rutherford backs cattering spectrometry (RBS) has been used to determine the depth of modifi cation achieved and to provide compositional depth profiles of modified PVd F samples. The complex chemical nature of the modified substrate, and the o verlap of the elemental scattering edges within the depths involved (up to 1.4 mum), create RBS spectra which are difficult to interpret. The DataFurn ace software has been applied to the data, leading to excellent results. De fluorination and oxygenation of PVdF occurs on treatment with NaOH and PTC. Through the use of samples prepared with the aim of establishing the kinet ics of the modification, a mechanism concerning elimination of fluorine fol lowed by oxygenation, is shown to occur. The RBS analysis indicates that th e kinetics of the defluorination reaction follows the Case 1 (Fickian) diff usion law, and that the depth of treatment is of the order of 1.4 mum. (C) 2001 Kluwer Academic Publishers.