Silver award

Formation and Stability of Tannic Acid and Gelatine Multi-layers

In recent years, there has been a huge interest in molecular multilayers assembled through layer-by-layer techniques. Conventional analysis methods are incapable of analysing real time formation of multilayers or are extremely costly. In contrast, precision ellipsometry (PREL) is significantly cheaper, has a precision of up to the nanometre range and allows for quantitative real‐time measurement and assessment of molecular interactions and its kinetics. We studied the layer-by-layer assembly of gelatine and tannic acid multilayer films using PREL and investigated their stability under different pH conditions. The films of up to three bilayers of gelatine and tannic acid were unstable in alkaline conditions. In acidic conditions, multilayers with tannic as topmost layer were stable; while if the topmost layer was gelatine, it was removed down to the preceding tannic layer. The use of PREL enabled real-time quantitative measurement of tannic acid and gelatine multi-layer formation and revealed the conditions where they can serve as either protective or sacrificial films.