We propose a theory of spontaneous curvature of 2D comblike macromolecules with incompatible side chains of types A and B. It is expected that the side chains of both types are able to change their positions with respect to the backbone. We predict two mechanisms of curvature. In the case of strong incompatibility of the side chains, their complete segregation with respect to the backbone is responsible for the formation of the so-called "energetic" curvature that is a result of the difference in the length (or in the number) of the A and B chains. In the case of moderate incompatibility, partial mixing of the A and B side chains on the convex side of the molecule (a flip of shorter chains to the side of longer chains) can be entropically favorable. In this case, the stretching of the side chains decreases. The radius of the entropic curvature is determined by the length of the longer side chains.