Crack-Interlocked Metal/Elastomer Interfaces for Preload-Adapted Backside Pressure Sensing

Area of Science:

• Materials Science
• Mechanical Engineering
• Sensor Technology

Background:

• Flexible pressure sensors are vital for embedded and backside monitoring.
• High sensitivity sensors often struggle with preloads, limiting their use under static loads.
• Existing sensors require direct contact, unsuitable for protected sensing layers.

Purpose of the Study:

• To develop a flexible pressure sensor that resolves small pressure variations under large static loads.
• To overcome the sensitivity limitations of current sensors when subjected to preloads.
• To enable pressure sensing in mechanically biased and embedded configurations.

Main Methods:

• Fabrication of a crack-interlocked ridge structure using PDMS micro-ridge arrays and a Pt conductive layer.
• Utilizing the interlocked architecture to convert compression into localized tensile deformation.
• Investigating the crack-mediated resistance transition for pressure sensing.

Main Results:

• Achieved a maximum local sensitivity of 2582.8 kPa^-1 within a designed transition window.
• Demonstrated reproducible responses over 1000 loading-unloading cycles.
• Shifted the active sensing window from 50-700 kPa by varying interlayer thickness.

Conclusions:

• The crack-interlocked interface design enables mechanically programmed pressure windows for flexible resistive sensors.
• This approach is suitable for preload-adapted pressure-change detection in embedded monitoring.
• The sensor successfully detected small additional loads in a backside-mounted configuration.