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Flexible electronics are a growing technology in the field of additive electronic manufacturing. Due to their flexible characteristics, these electronic devices can experience large and complex strains during their applications as compared to traditional rigid electronic devices. These large and complex strains can lead to mechanical failure of the materials that flexible electronic devices are fabricated from. Common mechanical failures of these materials include cohesive cracking through their thickness and interfacial cracking between dissimilar materials. It is therefore important to have techniques to measure the mechanical properties of these materials to design future flexible electronic devices with improved reliability and to survive their extreme user conditions. The mechanical characterization method utilized in this research project measures the interfacial fracture toughness between conductive ink films and the flexible substrate they are printed on using a custom built interfacial wedge tester. The interfacial wedge tester fabricated here was improved from previous experiments and was designed to be simple, reliable and readily fabricated. During the research, the design of the interfacial wedge tester was improved by increasing the precision of hardware and accommodating a fixed optical measurement device. The specific materials used in this research project are Novacentrix JS-B25P Silver Nanoparticle Ink printed on a thin and flexible PET substrate (Novacentrix Novele Printing Media).The silver conducting ink layer of samples was exposed to elevated humidity conditions using an environmental test chamber to simulate real-world use applications. These elevated humidity exposure silver ink samples were compared to a control group of silver ink samples that were exposed to room temperature/humidity conditions. After humidity exposure, silver ink samples were allowed to dry at room temperature/humidity conditions for varying lengths of times. The results from the experiment show that high humidity exposure, in combination with prolonged dry time, can have a beneficial effect in the interfacial fracture strength of the interface between the silver conducting ink and its flexible substrate.
Research and Creative Experience for Undergraduates (RCEU)
Mechanical and Aerospace Engineering
College of Engineering
Corbin, Joshua, "Development of Mechanical Characterization Techniques and Analysis of Flexible Electronic Materials" (2023). Summer Community of Scholars Posters (RCEU and HCR Combined Programs). 417.