Engineering of thermal & moisture transport properties of novel functional textiles using advanced materials

Abstract

Humanity has consistently endeavoured to improve its comfort level and quality of life throughout history. In light of the energy crisis and dramatic societal and environmental changes, there has been a pressing need for rapidly increased healthcare expenditures and awareness of personal health management. Healthcare is undergoing a transformation wherein continuous management and monitoring of individuals have become applicable daily. This thesis aims to improve the moisture and thermal management properties of advanced materials coated textiles and measure their moisture content for respiratory monitoring. Janus textiles are created with an asymmetric structure that exhibits different surface characteristics on two sides. By incorporating GO and rGO coatings, a Janus woven fabric can achieve high softness and flexibility while enabling efficient unidirectional liquid moisture transportation through a wetting gradient. The GO coating was applied using spray coating, whereas the rGO coating was realised through the thermal reduction of GO. The results of the moisture management test demonstrate that the Janus textiles possess an outstanding accumulative one-way transport index (R) of 1145% and an excellent overall moisture management capacity of 0.77 within 120 seconds. SEM and Raman analysis were conducted before and after the washing test, revealing that the GO and rGO nanosheets were tightly bonded to the fibre surface, indicating their durability in real-life applications. Apart from everyday wear, thermal comfort is essential to personal protective equipment. Taking inspiration from the adhesive proteins in mussels, the fibre surface of readily available nonwoven fabrics was deposited by dopamine via π-π stacking. Combined with the Janus structure, this formed a nano-thin and surfaced adherent PDA layer on one side. Applying PDA coating improves the filtration efficiency of a single PPNF, which increased by 3.4%~15.5% in contrast to the original efficiency. The highest R-value is 2481.38% with PDA/PPNF 24H, showing excellent unidirectional liquid moisture transport capability. The Janus PPNF fabric was subsequently integrated into a mask, leading to improved filtration efficiency (99.1%), thermal conductivity (138%), and moisture management performance (275%). Respiration is a tangible indication of health conditions and is closely related to various diseases. As the moisture content changes during the respiratory process, monitoring moisture variation during breathing is regarded as an applicable method to achieve non-contact respiratory monitoring. This study employs the self-polymerisation of dopamine to form a regenerable, customisable biocompatible film which exhibits sensitivity to moisture molecules. By incorporating AgNWs, the electrical conductivity of the film is enhanced. The prepared film is transferred onto electrodes and installed into a mask, enabling the real-time monitoring of moisture fluctuations during activities such as sleeping, walking and running. The system exhibits an ultrafast response (0.3s) and recovery (0.2s) speed.

Date of Award	1 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Hugh Gong (Supervisor) & Xuqing Liu (Supervisor)