Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | School of Fashion and Textiles | en_US |
| dc.contributor.advisor | Zheng, Zijian (SFT) | en_US |
| dc.creator | Zhong, Leni | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14515 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Liquid metal-based devices for energy harvesting and health monitoring through human sweat | en_US |
| dcterms.abstract | The skin, being the largest organ in the human body, contains various structures such as sweat glands, hair follicles, hair arrector muscles, and sebaceous glands. Except for specific areas like the vermillion border of the lips, the majority of the skin is equipped with sweat glands that continuously secrete sweat. Studies have reported the secretion of approximately 200-600 g·m⁻²·day⁻¹ of sweat from the skin. Sweat comprises water, ions, lactate, glucose, and other metabolites, which not only provide information about the health status but also contain biological energy. Hence, this naturally produced biological energy presents an environmentally friendly, renewable source that can be utilized to power wearable devices. To harness this biological energy from sweat, the development of stretchable and conformal wearable biofuel cells is necessary. Liquid metal-based materials, particularly gallium alloys, demonstrate promise due to their stretchability, conformal properties, and biocompatibility. In this study, liquid metals were employed to fabricate stretchable biofuel cells aiming to harvest energy from sweat and to develop sweat sensors to detect analytes such as glucose, lactate, sodium ions, and potassium ions in sweat. | en_US |
| dcterms.abstract | We utilized screen-printing method and transfer-printing method to pattern liquid metal circuits on polydimethylsiloxane (PDMS) substrates, which resulted in a metal-polymer conductor (MPC). The MPCs are with a maximum tensile strain of over 200%. After structural designing of the liquid metal-based biofuel cell patch, it allowed the carbon electrodes of the biofuel cell to retain their shape even when subjected to a strain of 40%. By modifying glucose oxidase or lactate oxidase, we fabricated glucose biofuel cells and lactate biofuel cells, respectively. With 0.2 mM glucose, the glucose biofuel cell attained a maximum power density of 14.11 μW·cm⁻². With the lactate concentration of 15 mM, the lactate biofuel cell achieved a maximum power density of 31.00 μA·cm⁻². By connecting extra booster module to harvesting energy, the biofuel cell patch was used to power wearable sensors, such as temperature, oximeter, and heart rate sensors, to monitor subjects' physical metrics during exercise. | en_US |
| dcterms.abstract | In addition, we employed electrospinning technology to fabricate an air-permeable stretchable thermoplastic polyether urethane (TPU) electrospun mat. We successfully developed an air-permeable biofuel cell mat based on liquid metal by combining this electrospun mat with stretchable, low-resistance sponge-like carbon electrodes (SLCEs). This innovative design makes the mat breathable (passing 5.42 g·m⁻²·h⁻¹ water in 60% humidity) while maintaining its stretchable characteristics. These biofuel cells demonstrated the maximum power density of 219 μW·cm⁻³ with 15 mM lactate. Directly connecting the biofuel cell with strain sensors can indicate the strain of sensors by the output current change. | en_US |
| dcterms.abstract | At last, we built a profile of sweat that showed the pH of sweat to be acidic, lactic acid concentration is in the range of 4-82 mM, glucose concentration in sweat is in the range of 16-200 μM, sodium ion concentration is the highest at 52-266 mM, and potassium ion concentration is lower at 10-39 mM, the calcium ion concentration is 80-453 μM. We employed screen printing liquid metal-based sweat sensors for sweat detection. Additionally, we tackled the issue of electrochemical impurities present in real samples by incorporating an extra working electrode without any active substances into the system, effectively eliminating interference during analysis. We applied such liquid metal-based sweat sensors in situ to record and analyze glucose, lactate, sodium, and potassium changes of the subject during exercise. | en_US |
| dcterms.abstract | In summary, the thesis highlights the potential of utilizing sweat as a renewable and clean energy source to power wearable devices and an indicator of health status. Liquid metal showed promise for developing such wearable biofuel cells and sweat sensors due to their stretchability, conformal ability, and biocompatibility. | en_US |
| dcterms.extent | xviii, 141 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2024 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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