During the last thirty years, several (families of) functionals have been defined which model self-avoidance: their values tend to infinity if an embedded object degenerates, e.g., if a sequence of closed simple curves converges to a curve with a self-intersection. Many of these functionals exhibit regularizing effects: they not only ensure embeddedness but in fact provide some sort of curvature measure. They are interesting objects per se: in many cases the first variation turns out to be an elliptic pseudo-differential operator which under certain conditions permits to derive smoothness of critical points. On the other hand, repulsive functionals can be used to model impermeability of elastic objects: we present an example in which they are are applied to the evolution of inextensible curves under the elastic flow.