AbstractThe adhesion of spuncast polyimide layers is critical to the success of manufacturing multilayer polyimide structures. We have measured the interpenetration between a spuncast layer of the meta isomer of poly(amic ethyl ester) (PAE) precursor of PMDA 4,4′ ODA and the corresponding partially-imidized PAE base layer using forward recoil spectrometry (FRES). Measurements made with FRES show that interpenetration decreases rapidly as the base layer imide fraction f increased, with a corresponding decrease in adhesion measured with a T-peel test. In the region of f > 0.8, differences in interfacial adhesion are still observed while the interfacial widths are too narrow to be differentiated with FRES. For this reason, the use of other high resolution techniques for profiling the polyimide-polyimide interface such as nuclear reaction analysis, dynamic secondary ion mass spectrometry, and neutron reflectometry will be necessary to accurately correlate interpenetration with adhesion.