Fig. 2.

Removing or controlling confounding factors derived from structure generation. (A-C) Achieve a well-controlled “one structural parameter” difference: (A) Schematic of generating topographic structures choosing replica molding as method and PDMS as substrate material. (B) SEM images of nanostructures generated by PDMS diluted with n-hexane in different volume ratios, and (C) different micro/nano topographic structures generated after optimizing the viscosity of PDMS. (D-E) Ensure consistent chemical properties: (D) Chemical formula of PDMS. (E) FTIR showed the chemical bonds of generated topographic structures. (F) XPS showed the chemical composition and structure of generated topographic structures. (G-I) Achieve consistent structure-independent physical properties: (G) Young's modulus of PDMS in different experimental conditions. (H) Young's modulus of the same topographic structure that prepared under different conditions. (I) Young's modulus of different topographic structures that prepared under the same condition.