This thesis includes two parts. One is the application of dewetting of polymer films in the fabrication of micrometer scale surface patterns. The other is fundamental study on the dewetting of a polymer brush by a chemically identical homopolymer melt (or autophobic dewetting). The system studied is polystyrene (PS) homopolymer melt on a PS end-functionalized with an OH group, end-grafted on silicon....[ Read more ]

This thesis includes two parts. One is the application of dewetting of polymer films in the fabrication of micrometer scale surface patterns. The other is fundamental study on the dewetting of a polymer brush by a chemically identical homopolymer melt (or autophobic dewetting). The system studied is polystyrene (PS) homopolymer melt on a PS end-functionalized with an OH group, end-grafted on silicon.

1. Application of dewetting for fabrication of micron-scale surface patterns

On the basis of spinodal dewetting of polymer film with preexisting nanogroove defects introduced by unidirectionally rubbing the film surface with a piece of fabric, we fabricated two types of remarkably well-aligned large-area pattern in the micron scale. One is a long strip pattern with period of about 2 μm. The other is a pattern comprising alternating horizontal and vertical micro-grooves.

2. Dewetting of a polymer brush by a chemically identical polymer melt.

Grafting or adsorbing polymers onto surfaces is often used to modify surface forces and has important technological applications in many areas. In this thesis, the dewetting instability of PS/Brush/SiO₂/Si system was investigated as a function of initial homopolymer thickness, annealing time, relative homopolymer molecular weight and grafting density. It was found that only relative homopolymer molecular weight and grafting density have significant influence on the equilibrium thickness of dewetted films, i.e., the thickness of the residual film after dewetting. Our result, to our knowledge, is the first experimental result that shows good agreement with existing theories for autophobic dewetting of polymers.