The peel force of a PVDF/3-APS/Si joint and a PVDF/3-APS/Al joint can reach the same level by treating the Si substrate with greater than or equal to 0.3% 3-aminopropyltriethoxy silane (3-APS) solution and treating the aluminum substrate with NH3 solution (pH 10.5) first and then with greater than or equal to 3% 3-APS solution. Scanning electron micrographs show that the interfacial adhesion mechanisms of PVDF/3-APS/Si joints and PVDF/3-APS/Al joints are different. In the peel test, the PVDF [poly(vinylidene fluoride)] break surfaces from PVDF/3-APS/Si joints reveal striations on the surface and less plastic deformation. The significant plastic deformation of the PVDF at the break surface may result from the deeper interpenetration of S-APS with PVDF in the PVDF/3-APS/Al joint than in the PVDF/3-APS/Si joint. The peel force of PVDF film/substrate joint depends on many factors : film thickness, peel rate, concentration of coupling agent, the treatment time of the coupling agent on the substrate, and the substrate pretreatment.