Property Leading to Morphological Instability

This letter describes that morphological instabilities, such as the nonsimplification of the interface and the increase in interface perturbation, which are required for the formation of matters with complex appearance, is caused by a property, that is, "the driving force of interface development that increases with the increase in curvature", with the aid of the qualitative properties of a primitive and general evolution equation. This result has a certain universality owing to these primitiveness and generality; thus, it has the potential of playing an essential role in the realization of diverse phenomena that generate matters with intriguing appearance and in the actual manufacture of matters with complex appearance.