Project 8

Fabrication and Characterization of Aerosol Jet Printed Carbon-Based Strain Sensors on Flexible Substrates

(Drs. kevin walsh & dilan ratnayake, eCE)

Aerosol Jet Printing (AJP) provides a mask-less, additive manufacturing approach capable of depositing fine conductive features directly onto flexible substrates, enabling compact and customizable electronics. In this project, the student will use the AJP system to print carbon-based conductive ink traces with different geometries, such as serpentine, grid, and linear patterns, on flexible substrates (such as polyimide or PET). The work will involve establishing process conditions—varying print speed, atomizer and sheath flows, number of passes, and curing or sintering parameters—to achieve uniform, low-resistance carbon traces. Once printed, the traces will be electrically characterized under no load to determine baseline resistance and sheet resistivity, and then mechanically challenged by controlled bending or stretching to evaluate the change in resistance versus applied strain. From these data, the gauge factor, linearity, repeatability, hysteresis, and drift of the printed strain sensor will be quantified. The student will also develop a simple statistical or regression-based model correlating printing and curing parameters with sensor performance, thus identifying critical factors affecting performance. The accompanying figure highlights the printing versatility of the AJP system, demonstrating its ability to deposit narrow 30 µm silver lines on various complex surfaces, including glass, silicon cavities, polyimide diaphragms, and carbon fiber rods. At the end of the 10-week period, the student will deliver a written report and present a poster summarizing the fabrication, characterization, and analysis of the carbon-ink-based strain sensors.

References

•        Ratnayake, D., Curry, A. and Walsh, K., 2021, June. Demonstrating a new ink material for aerosol printing conductive traces and custom strain gauges on flexible surfaces. In 2021 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (pp. 1-4). IEEE.

•        Ratnayake, D., Curry, A.T., Qu, C., Usher, J. and Walsh, K., 2021, June. Characterizing the Conductivity of Aerosol Jet Printed Silver Features on Glass. In International Manufacturing Science and Engineering Conference (Vol. 85079, p. V002T08A007). American Society of Mechanical Engineers.

•        Ferris, C., Ratnayake, D., Curry, A., Wei, D., Gerber, E., Druffel, T. and Walsh, K., 2022, June. Characterizing the Conductivity of Aerosol Jet Printed Silver Traces on Glass Using Intense Pulsed Light (IPL). In International Manufacturing Science and Engineering Conference (Vol. 85802, p. V001T07A015). American Society of Mechanical Engineers.

•        Olowo, O.O., Zhang, R., Wei, D., Ratnayake, D., Jackson, D. and Popa, D.O., 2022, July. Aerosol Jet Printed Tactile Sensor on Flexible Substrate. In 2022 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (pp. 1-4). IEEE.

•        Ratnayake, D., Curry, A., Qu, C., Wei, D., Gerber, E. and Walsh, K., 2023. Optimizing the Conductivity of a New Nano-particle Silver Ink for Aerosol Jet Printing and Demonstrating its use as a Strain Gauge. IEEE Journal on Flexible Electronics.

•        Olowo, O.O., Wei, D., Ratnayake, D., Goulet, B., Curry, A., Sherehiy, A., Zhang, R. and Popa, D.O., 2022, July. PEDOT: PSS Polymer Aerosol Jet-printing for Robotic Skin Sensors. In 2022 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (pp. 1-4). IEEE.