Periodic mass shedding of a retracting solid film step
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 {alpha} between 30 and 180{degree}. For smaller {alpha}, a small-slope late-time solution is found that agrees with the numerical solution for {alpha} = 30{degree}. Thus, the complete range of {alpha} is covered. The long-time retraction speed and the distance traveled per cycle agree quantitatively with experiments.
- Research Organization:
- Louisiana State Univ., Baton Rouge, LA (US)
- Sponsoring Organization:
- USDOE; American Chemical Society
- DOE Contract Number:
- FG02-95ER25241
- OSTI ID:
- 20075928
- Journal Information:
- Acta Materialia, Vol. 48, Issue 8; Other Information: PBD: 11 May 2000; ISSN 1359-6454
- Country of Publication:
- United States
- Language:
- English
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