Abstract
A semi-infinite, uniform film on a substrate tends to contract from the edge to reduce the surface energy of the system. This work studies the two-dimensional retraction of such a film step, assuming that the film evolves by capillarity-driven surface diffusion. It is found that the retracting film edge forms a thickened ridge followed by a valley. The valley sinks with time and eventually touches the substrate. The ridge then detaches from the film. The new film edge retracts to form another ridge accompanied again by a valley, and the mass shedding cycle is repeated. This periodic mass shedding is simulated numerically for contact angle α between 30 and 180°. For smaller α, a small-slope late-time solution is found that agrees with the numerical solution for α = 30°. Thus, the complete range of α is covered. The long-time retraction speed and the distance traveled per cycle agree quantitatively with experiments.
Original language | English (US) |
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Pages (from-to) | 1719-1728 |
Number of pages | 10 |
Journal | Acta Materialia |
Volume | 48 |
Issue number | 8 |
DOIs | |
State | Published - May 11 2000 |
Funding
The Department of Energy (DE-FG02-95ER25241 to P.W.V., M.J.M. and S.H.D.), the Donors of Petroleum Research Fund, administered by the American Chemical Society (PRF♯34049-G5 to H.W.), and the Louisiana Board of Regents (Research Competitiveness Subprogram, LEQSF1999-02-RD-A-21 to H.W.) are acknowledged for supporting this research.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys