Partial and complete wetting of thin films with dynamic contact angle

The wetting of thin films depends critically on the sign of the spreading coefficient S = γ S G − ( γ S L + γ L G ). We discuss the cases S < 0, S = 0, and S > 0 for transient models with contact line dissipation and find that the use of a dynamic contact angle solves problems for S > 0 that models might otherwise have. For initial data with a non-zero slope and S > 0, we show that there exists a finite time t p at which the contact angle of the thin film goes to zero. Then, a molecular precursor emerges from the thin film and moves outward at a constant velocity.