By combining a liquid primer and a plasma jet system, a new route to improved adhesion on various substrates has been developed. The liquid primer is introduced as an aerosol into a plasma jet and the resultant active species are deposited as a polymer coating on adjacent surfaces. Careful control of the plasma parameters produced a dry polymerised coating with functional chemistry designed to enhance the adhesion of silicone sealants to two substrates. This paper describes the surface chemistry and adhesion properties of various coatings on both a plastic and a metal substrate. Selected surface analysis techniques were coupled to both wet and dry adhesion testing to characterise the factors that control adhesion within the system. Mechanical testing indicates that adhesion was improved by several orders of magnitude.