Self-assembled constructs in solution and on interfaces are remarkable tools for the elaboration of functional responsive materials. Water-soluble polymers and amphiphilic polymers, whether natural or synthetic, often adopt well-defined conformations in solution and at the air/water or solid/water interface, which are amenable to further association by non-covalent interactions. I will present several examples to illustrate this strategy, based on current projects in my research group aimed at the elaboration of diagnostic tools and smart nanoparticles