Dual Imprinted Polymer Thin Films via Pattern Directed Self-Organization.

Synthetic topographically patterned films and coatings are typically contoured on one side, yet many of nature's surfaces have distinct textures on different surfaces of the same object. Common examples are the top and bottom sides of the butterfly wing or lotus leaf, onion shells, and the inside versus outside of the stem of a flower. Inspired by nature, we create dual (top and bottom) channel patterned polymer films.

Capillary wave confinement-induced stabilization of polymer films.

We show that temporary confinement of polystyrene thin films by an elastomeric capping layer possessing nanoimprinted subcapillary wavelength (λ << λcap (20 μm)) line channels (amplitude A ≈ 120 nm) can suppress film dewetting on thermodynamically unfavorable substrates by arresting the amplitude growth and in-plane propagation of the destabilizing surface capillary waves. Confinement by either a smooth elastomer capping layer (A ≈ 1 nm) or with pattern features above the threshold dimension only retards dewetting but does not prevent it. The nanoimprint pattern is therefore essential to preventing dewetting, illustrating that only the penalty of elastomer deformation and interfacial tension reduction is insufficient.