Model thin films of controlled thickness and composition
Polimery 2000, No 7-8, 528
SummaryTwo methods to prepare tailor-made thin films are described. One method uses the „coupling monolayer concept”, viz., a thin film made of a passivating organic compound coupling the metal surface with an (epoxy) polymer encapsulating layer. The passivating monolayer was found to be about 10 nm thick, i.e., comprising about 20 monolayers of stearic acid, deposited on the electronic tester surface (Al) by a Langmuir-Blodgett (LBT) transfer process. The composition of the layer was determined by a three-step elimination of organic compounds used to passivate the Al surface, including depositing on the surface of electronic testers and highly accelerated aging tests. Anthranilic acid and dodecylamine were selected as most promising passivating agents, either deposited as an individual passivating layer or mixed with as encapsulating epoxy resin or polyacrylurethane (Fig. 3). Another method is to construct multilayers from polyelectrolyte polymers by the self-assemblying technique. Donor-Acceptor (DA) „smart” molecules were added to the polyelectrolytes to prepare thin films endowed with potential computer memory properties. Three types of polyelectrolyte multilayers were prepared involving „smart” molecules based on sulfonated polystyrene (PSSA) as a polyanion and poly(4-vinylpyridine) hydrochloride (P4VP) as a polycation and tetracyanoquinodimethane (acceptor A) and Cu 14 (acceptor D) (Figs. 4 and 6). Contact angle measurements (Figs. 7, 8) allowed to find the maximum degree of incorporation of „smart” molecules to occur in type III multilayers (PSSA/DA + P4VP/DA).