Crack Initiation of Printed Lines Predicted with Digital Image Correlation

Area of Science:

• Materials Science
• Nanotechnology
• Mechanical Engineering

Background:

• Roll-to-roll printing offers cost-effective metallic film deposition compared to vacuum methods.
• Printed films require understanding of their structure-property relationships for reliable applications.
• Sintering of suspended metallic particles is key to forming conductive printed films.

Purpose of the Study:

• To evaluate the electro-mechanical behavior of printed silver (Ag) films.
• To investigate crack initiation and propagation during tensile loading.
• To correlate film microstructure with mechanical failure modes.

Main Methods:

• In situ resistance measurements during tensile straining.
• In situ imaging using confocal laser scanning microscopy.
• Digital image correlation (DIC) analysis of microscopic images.

Main Results:

• Cracks initiated earlier in thicker film regions (crests) compared to thinner regions (troughs).
• Higher defect density and increased thickness in crests contributed to earlier crack initiation.
• Electro-mechanical response and fracture behavior were directly linked to printing defects and film topography.

Conclusions:

• Printing defects and film thickness variations significantly influence the mechanical integrity of printed metallic films.
• In situ DIC is effective for visualizing crack initiation in printed films under strain.
• Understanding these failure mechanisms is crucial for optimizing printed electronics and flexible devices.