In recent years, amphiphilic block copolymers have attracted great interest for their ability to self-assemble, which allows them to form various bottom-up nanostructured materials. Here we report the fabrication of a nano-structured membrane from sequential spray deposition of cationic and anionic di-block copolymer nanoparticles. Reversible Addition Fragmentation Chain Transfer (RAFT) aqueous emulsion polymerisation method was used to synthesis the cationic and anionic diblock copolymer nanoparticles via polymerisation induced self-assembly (PISA). The thin film membrane was then prepared by sequential deposition of these oppositely charged nanoparticles using spray coating. The prepared nanoparticles and the resulting membranes were fully characterised using microscopy methods (TEM, SEM and AFM), dynamic light scattering (DLS) and filtration tests using pure water and salt solution.