Solvent Vapor Assisted Directed Dewetting of Polymer Thin-films for Large Area Patterning
A. Verma, A. Sharma
Indian Institute of Technology Kanpur, IN
Keywords: dewetting, thin-films, large area patterning
Abstract:Polystyrene thin-film on silicon wafer is a well studied system for dewetting of the polymer thin-films. Size and distribution of the dewetted structure can be tuned by varying the initial film thickness and the interfacial tension. In absence of any external constraint, dewetting generates isotropic and random distribution of polymer droplets. Here a technique is demonstrated to produce regularly aligned polymer droplets of various shapes and sizes by selective exposure of polymer thin-film to the solvent vapor. Thin-films of PS is coated on silicon wafer and masked with commercially available TEM grids with various opening size. Then it is exposed to the solvent (toluene) vapor for different durations which initiates the hole formation in the film. The capillary force between the film and the mask directs polymer to accumulate in the unexposed regions. Now the mask can removed and the pre-patterned films can be further exposed to the solvent vapor which further reorganizes the polymer droplets on the substrate. The polymer loaded with metal nanoparticles (Silver and Nickel) has shown the similar dynamics and all the metal particles remain with in the polymer droplets.