Free Motion of Thin Solid Film on Liquid Surface as a Route Towards Self-Organization

Abstract

In this paper, we present the spontaneous formation of an unusual type of ordered structures in thin metal film systems deposited on silicon oil surfaces by a thermal evaporation method. These structures are composed of a large number of parallel rectangular-shaped domains and exhibit anti-symmetric characteristic. The experiment shows that thin solid films can move freely on liquid surfaces due to the near-zero adhesion of the solid-liquid interface, resulting in superposition of the films and formation of the ordered structures. Compressive stress gradient in the films is shown to be the driving force for self-organization. All characteristics of the ordered structures are discussed in detail based on special mechanical behaviors of these nearfree sustained films.

Formation Mechanism and Surface Evolution of Silver Films Sputtering Deposited on Silicone Oil Substrates

“…[1][2][3][4][5][6][7][8][9][10] The studies show that the formation process of metal films on liquid surfaces generally includes the following stages: growth of atomic compact clusters, aggregation of branched islands, and finally, the formation of continuous films. In addition, the deposited atoms, compact clusters, and branched islands possess large mobility and they can diffuse and rotate on the liquid surfaces freely, 1,2 which indicates that the interaction between the metal film and the liquid substrate in the tangent direction is very small.…”

“…In addition, the deposited atoms, compact clusters, and branched islands possess large mobility and they can diffuse and rotate on the liquid surfaces freely, 1,2 which indicates that the interaction between the metal film and the liquid substrate in the tangent direction is very small. Therefore, various characteristic patterns such as chrysanthemum-shaped wrinkles, 3 parallel sinusoidal cracks, 4 and rectangular structures [5][6][7][8] always emerge in these nearly free sustained films, in which the residual internal stress is shown to be the driving force for pattern formation. Furthermore, due to the soft and unstable properties of the underlying liquid substrate, the microstructure and surface morphology of the film can usually evolve in a vacuum or atmosphere condition for several hours before the system reaches a stable state with minimum free energy.…”

“…Furthermore, due to the soft and unstable properties of the underlying liquid substrate, the microstructure and surface morphology of the film can usually evolve in a vacuum or atmosphere condition for several hours before the system reaches a stable state with minimum free energy. [1][2][3][4][5][6][7][8][9][10] In this paper, we report the formation mechanism and surface evolution of thin silver films deposited on silicone oil substrates by a DC-magnetron sputtering method. The formation process is found to be quite similar to other metal films on liquid substrates prepared by various techniques.…”