Formation of Plasma Polymer Layers with Functional Groups of Different Type and Density at Polymer Surfaces and their Interaction with Al Atoms

Summary: Monotype functionalizations with different types of functional groups (OH, NH 2 , COOH) on polypropylene and poly(tetrafluoroethylene) surfaces were synthesized using pulsed plasma‐initiated homo‐ or copolymerization of functional group‐carrying monomers. The maximum concentrations of functional groups were 31 OH, 18 NH 2 or 24 COOH groups per 100 C atoms using allyl alcohol, allylamine or acrylic acid respectively as the monomer. The measured peel strengths of aluminium deposits increased linearly with the concentration of functional groups. Near the maximum concentration of OH (>27 OH/100 C atoms) or at moderate concentrations of COOH groups (>10 COOH/100 C atoms), constant (maximum) peel strengths were measured due to the mechanical collapse of one component in the composite (cohesive failure). Interface failures in Al‐PP composites were found with COOH, NH 2 and OH groups and cohesive failures were seen when higher concentrations of COOH groups were applied (>10 COOH/100 C atoms). Dependence of Al peel strength in Al‐plasma polymer‐PP systems on the type and density of functional groups in plasma polymer interlayers. image Dependence of Al peel strength in Al‐plasma polymer‐PP systems on the type and density of functional groups in plasma polymer interlayers.