In-situ monitoring on dynamics of solute transport in polymer films

Abstract

17A new and non-invasive technique based on confocal laser scanning microscopy 18 (CLSM) that allows the visualization of penetrant diffusion in-situ has been 19 developed and was applied to quantify local solute dynamics in polymeric films. The 20 effectiveness of the proposed technique was demonstrated using a model penetrant, 21 rhodamine 6G (Rh-6G), and a system of polyvinyl alcohol (PVA) films with different 22 degree of cross-linking, and different content of montmorillonite (MMT) clay. The 23 penetrant's transport across PVA films were monitored by measuring the time 24 evolutions of through thickness fluorescence intensity profiles. These profiles were 25 then converted to concentration profiles, which allow local diffusion coefficients of 26 the model solute (i.e. Rh-6G) to be determined. The developed methodology was 27 M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2 applied to both single layer and bilayers films and local diffusion heterogeneity was 1 detected. Hence the technique developed can be applied to multi-layer films, and can 2 be beneficial to film developments for packaging and filtration technology. 3