Observation of dynamic behavior of lithographically induced self-assembly of supramolecular periodic pillar arrays in a homopolymer film

The dynamic behavior of lithographically induced self-assembly (LISA), a newly discovered pattern formation phenomenon, was recorded and analyzed with real time video. Two surprising and intriguing phenomena were observed. First, a LISA pillar array was formed in an orderly manner starting under the corners of a mask pattern, then the edges, and later propagating to the center of the mask pattern. Second, the time interval between the formation of two subsequent LISA pillars has a shell structure. The observation presents evidence critical to uncovering the physical origin of this phenomenon, which is believed to be related to the interplay of electrodynamics, fluid hydrodynamics, and polymer chemistry at the nanometer scale.