Fig. 3: Structure analysis and proposed mechanism for pattern formation.
a Optical diffraction taken from a line pattern with LED diode laser. b AFM images of the obtained line patterns which show line features of 300 nm and 150 nm. c Proposed pattern formation mechanism which shows schematic energy-concentration relation of oversaturated solution film. Eint is the interface energy and E* is the critical energy density for phase transition to happen. A and B are the first and secondary instability points, and the red colored curve corresponds to the case when PS is added into the solution. d Microstructure of an underdeveloped square-grid pattern where a branching from vertical primary lines is seen. White colored arrows indicate misalignment of the branches. The AFM image (inset) shows a modulated feature with unstable lines. e Modulated microstructure (top panel) which can be fitted with superposition of two waves (bottom panel). f Microstructure which shows ‘line-end’ dislocation emerged in an array. g Microstructure which shows a dislocation fused with neighbor line before passing through it (detailed in Fig. 4b and Supplementary Movie 2).
