Special Session 54: Nonlocal dynamics and complex patterns in phase-separation

A sixth-order Cahn--Hilliard equation for curvature effects in pattern formation

Pierluigi Colli
University of Pavia
Italy
Co-Author(s):    
Abstract:
This talk is concerned with a sixth-order Cahn--Hilliard system, which represents a higher-order variant of the well-known Cahn--Hilliard equation. In the system, the evolution equation is complemented with a source term, where the control variable enters as a distributed mass regulator. The presence of further spatial derivatives in the sixth-order formulation enables the model to capture curvature effects, for a more accurate description of isothermal phase separation dynamics in complex materials systems. The well-posedness and optimal control are discussed for the related initial and boundary value problem. Well-posedness is shown when assuming a smooth double-well potential as part of the free energy. Then, the optimal control problem is addressed: existence of optimal controls is established, and the first-order necessary optimality conditions are characterized via a suitable variational inequality involving the solution to the adjoint problem. These results have been obtained in a recent collaboration with G. Gilardi (University of Pavia), A. Signori (Polytechnic of Milan) and J. Sprekels (WIAS Berlin).