A New Way Of Making Complex Structures In Thin Films

Block copolymers, which are self-assembling materials known to form various predictable, regular patterns, can now be made to form much more complicated patterns, according to a team of researchers. It could lead to the development of new materials design fields.

The polymers can self-assemble in designs that differ from conventional symmetrical arrays thanks to a phenomenon that the team has discovered.

Block copolymers that naturally arrange their chain-like molecules into periodic structures are known as self-assembling block copolymers. Researchers discovered that when a thin film of the block copolymer was formed on the top of a substrate with a repeating pattern of lines or pillars, the patterns from the substrate would be replicated in the self-assembled material. However, this technique could only generate straightforward designs like grids of dots or lines.

There are two distinct, mismatched patterns in the new approach. Two patterns are produced: an inherent pattern made by the self-assembling copolymer and the other is a series of posts or lines etched on a substrate material. The substrate, for instance, might have a rectangular pattern, and the copolymer might create a hexagonal grid all by itself. The researchers did not discover a poorly ordered block copolymer arrangement, which is what one might anticipate. Instead, something much more complex and surprising was taking shape.

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