| Author: | Huang, Junxian |
| Title: | Study on surface microstructure engineering of one-dimensional advanced materials with customizable functionalities |
| Advisors: | Xu, Bingang (SFT) |
| Degree: | Ph.D. |
| Year: | 2024 |
| Subject: | Electronic textiles Textile fabrics -- Technological innovations Wearable technology Hong Kong Polytechnic University -- Dissertations |
| Department: | School of Fashion and Textiles |
| Pages: | xxvi, 183 pages : color illustrations |
| Language: | English |
| Abstract: | The rapid progress in advanced functional fibers (AFFs) offers unique superiorities in wearable electronics, artificial intelligence, and healthcare monitoring. However, there remain considerable challenges for AFFs to fulfill specific requirements of advanced applications due to their low electrical outputs, limited material choices, and difficulty in regulating microstructures on narrow and curved surface of the fibers. This thesis aims to develop and fabricate high-performance AFFs with customizable functionalities via surface microstructure engineering. Through investigating the formation mechanism of the honeycomb porous microstructures (HPMs) on fiber substrates that are induced by the breath figure (BF) method followed by developing the AFFs with customized functions, this research study may create a new route for addressing the existing challenges. Firstly, in this study, the dynamic formation mechanisms of honeycomb porous microstructures (HPMs) on one-dimensional (1D) nonplanar surfaces induced by the BF method were systematically investigated. The novelty of this methodology is that by manually terminating the water droplet condensation process at different periods, the different stages of BF including nucleation, growth and self-assembly can be readily achieved and fixed, thus providing deeper insight into the formation mechanism of HPMs on nonplanar substrates. The experimental factors such as solvents, concentration, and polymer bricks, relative humidity (RH), temperature, the diameters of substrates, that affect the formation of HPMs were also investigated in detail. The comprehension of HPMs mechanism on nonplanar fiber surfaces provides insights and guidance in regulating microstructures of fiber materials for developing AFFs with customizable functionalities. Subsequently, a novel kind of hybrid fiber that was surface engineered with HPMs (HF@HPMs) with functional nanomaterials incorporated in porous microstructures was developed. The obtained HF@HPMs demonstrated controllable surface microstructural morphologies by adjusting the experimental variables. A larger specific surface area and enhanced capacity to load the functional nanomaterials with a reduced embedding phenomenon were also achieved. Moreover, various functional nanocomponents, such as Ag nanowires (NWs), ZnO NWs, CuO nanoparticles (NPs), and TiO2 NPs, could be incorporated for developing HF@HPMs with customized functionalities, which endow the resultant fibers more application potentials in a broader range of fields. As a demonstration, TiO2/HF@HPMs that incorporate TiO2 nanoparticles were fabricated for enhanced photodegradation of organic pollutants. Thirdly, fabricating and regulating HPMs on 1D nonplanar fiber surfaces were proposed and systematically studied for developing AFFs with excellent energy harvesting and sensing performance. In particular, multifunctional silver-plated nylon fibers surface-engineered with HPMs (SNF@HPMs) were developed with the assistance of the BF method and were further fabricated into high-performance SNF@HPMs-based triboelectric nanogenerator (SNF@HPMs-TENG). The SNF@HPMs-TENG showed good electrical performances and long-term stability, which can be used to power portable electronics. Moreover, a self-powered wearable sensor with good sensing ability and durability was also developed for monitoring the bending, tactile, and frictional stimuli in a real-time manner. Lastly, a novel and nondestructive strategy to manufacture conductive NiCo-SSY@CPMs electrodes with porous hierarchical structures and mechanical stability for fiber-shaped supercapacitors (SCs) has been developed. The conductive and electroactive porous fiber electrodes were first fabricated by the BF method followed by hydrothermal growth with NiCo nanoflakes. The capacitive properties of the NiCo-SSY@CPMs showed a significant improvement owing to the high porosity and enhanced dispersive adhesion. The flexible and wearable all-solid-state ASC device with great electrochemical performance and mechanical reliability based on the NiCo-SSY@CPMs electrode was further assembled, showing a desirable energy density and power density, meanwhile possessing great cycling performance. In summary, the AFFs with controllable surface porous microstructures and customized functionalities have been successfully developed. The BF methods used for surface microstructure engineering are a facile and nondestructive technique, which can be applied to various 1D fiber materials meanwhile maintaining their intrinsic properties such as flexibility. Through the systematic investigation on the mechanism of BF-induced HPMs on fiber substrates as well as the combination of customized functionalities, the resultant fiber-shaped devices with enhanced performance can be used in photocatalysis, energy harvesting and storage, as well as sensing. This research study may shed light on the rational design of AFFs as efficient fiber-shaped materials/devices through precise manipulation of surface microstructures. |
| Rights: | All rights reserved |
| Access: | open access |
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