Coexistence and Coevolution of Wrinkle and Ridge Patterns in the Film-Substrate System by Uniaxial Compression

Area of Science:

• Materials Science
• Surface Physics
• Mechanics of Materials

Background:

• Wrinkles and localized patterns are common in nature and have practical applications.
• Understanding the interaction of multiple surface patterns in hard film-soft substrate systems remains a challenge.

Purpose of the Study:

• To investigate the formation and evolution of coexisting wrinkle and ridge patterns in metal films on PDMS substrates.
• To analyze the morphological transitions and underlying mechanisms of these complex surface patterns under uniaxial compression.

Main Methods:

• Experimental observation of pattern formation in metal films on poly(dimethylsiloxane) (PDMS) substrates under uniaxial compression.
• Application of compressive strain-driven surface instability theory.
• Finite element numerical simulations to model pattern evolution and mechanisms.

Main Results:

• Observed a morphological transition from localized ridges to coexisting wrinkles and ridges, and finally to sinusoidal-like structures with increasing compression.
• Characterized the evolution of surface patterns through three distinct stages.
• Demonstrated consistency between experimental observations and theoretical/numerical predictions of pattern amplitude and wavelength changes with strain.

Conclusions:

• The study elucidates the complex interplay between strain localization and multiple surface pattern formation in hard film-soft substrate systems.
• Provides a deeper understanding of morphological transitions driven by compressive strain.
• Offers insights applicable to designing and controlling surface topographies for various applications.