Guided alignment and positioning of single DNA molecules by a structured contact line on a block copolymer surface.

A nanostructured dynamical contact line is generated when the meniscus of a droplet of water solution is moving on the structured surface of a thin film of a block copolymer of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) because of the difference in the water contact angles on PS and PMMA. Such a structured receding contact line extends DNA molecules as in the molecular combing process. More importantly, it aligns DNA molecules following the position and orientation of the PMMA domains on the surface. The driving force of this phenomenon is discussed as the lateral motion of the locally modified contact line.