Characterization and fabrication of MWCNTs pressure sensors for pressure ulcers monitoring
Date
2017
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Publisher
University of Delaware
Abstract
This thesis presents a low cost, flexible, scalable, and piezoresistive pressure monitoring system to prevent pressure ulcers. Pressure ulcer is one of the biggest health care problems in this century. Diabetes, obesity, becoming bedridden, and restricting a wheelchair are the main causes to pressure ulcer. A pressure monitoring system can help prevent this health condition. To implement a pressure sensor during experimentation, Multi Wallet Carbon Nanotube (MWCNT) and Polydimethylsiloxane (PDMS) were chosen as core materials. The array system was developed by using molding approach and additive manufacturing. Four different concentrations of MWCNTs were mixed by weight (2%, 2.5%, 3%, and 4%) in silicone elastomer; each were studied separately. The MWCNT-PDMS composite was fabricated as a parallel plate structure mode with 4x4 arrays. ☐ The MWCNT-PDMS nanocomposite layer was sandwiched between two printed silver plates. Also, the electronic circuit was designed to get instant data from the array so that a color map can be created based on the pressure applied to the system simultaneously. The change in resistance value was observed when compressive forces were applied to the structures. A laser, nScrypt printer, and screen printer were utilized to fabricate this process. The piezoresistive pressure sensors were fabricated through a molding approach with a laser, and silver conductive plates were fabricated through an nScrypt printer. The first part of my thesis will explain a pressure ulcer, its causes-consequences, the devices that were used in this research overall and material properties and piezoresistivity feature. A number of samples were fabricated to determine percolation threshold of the MWCNT-PDMS composite. The remainder of the thesis will outline the fabrication process and the circuit design. The results of the system will exhibit a color map of the applied pressure. This research can benefit those who have pressure ulcers risk, and millions of people can maintain their health and finances.
Description
Keywords
Applied sciences, Additive manufacturing, CNT composite, Flexible sensors, Piezoresistance, Pressure ulcer