Preparation Of Stretchable Conductive Bandages And Research On Wearable Sensing Applications

Wearable mechanical sensors are capable of monitoring a variety of human physiological signals,which are important for monitoring and evaluating the health level and exercise capacity of human bodies.Due to the inherent limitations of flexible electronic materials,it is difficult to achieve both large response ranges and high sensitivities of mechanical sensors,which limits its application in the field of wearable mechanical sensing.In response to these requirements,researchers have improved the performance of wearable mechanical sensors through component and structural designs.However,this usually involves expensive components and complex preparation processes,making it difficult to develop wearable mechanical sensors with excellent performance through low-cost and easy-manufacturing methods.It becomes a key restriction for promoting their mass-production preparation and application.Therefore,the development of wearable mechanical sensors with excellent cost performance and their preparation methods is a key research direction in this field.In this thesis,stretchable resistive strain sensors with highly controllable sensitivity and response range are developed based on commercially available cohesive bandages with excellent performances and low cost.The effect of preparation parameters on their performances and sensing performance for pressure,tension and bending signals are systematically investigated to explore its feasibility as wearable sensors for monitoring mechanical signals related to human health level and exercise capacity.This work will create some theoretical and practical foundations for the development and application of flexible electronic materials and wearable mechanical sensors.The main contents of the paper are as follows:An electrospraying-based material preparation platform was established to develop conductive bandages(CBs)by using wrinkled,stretchable,biocompatible,breathable and inexpensive cohesive bandages as the flexible substrate materials,and carbon nanotubes(CNTs),which are mechanically stiff and brittle and easily to form cracks during deformation,as a conductive coating layer.The optimal preparation parameters of CBs were obtained by force-electric response testing and the prepared CBs have a wide response range(0-100%),adjustable sensitivity GF(24-580),low response time(120 ms),low Young’s modulus(84 kpa),and excellent stability under 5000 cycles of stretching.The optimal preparation parameters of CBs were obtained by extensively tuning preparation parameters,and the effects and mechanisms of the wrinkled and crack microstructures on their mechanoelectrical properties and mechanical sensing properties were revealed.The two critical factors,including the pre-stretching and mechanical training parameters,were investigated in depth,and the mechanisms of their regulatory effects was explored to on-demand obtain CBs with controllable sensitivities and response ranges.Based on the CBs with different mechanoelectrical properties prepared under different parameters,including CBs with large response range but low sensitivity for monitoring joint activities in different regions,CBs with intermediate response range and sensitivity for monitoring epidermal deformation induced by muscle activities in non-joint regions,and CBs with small response range but high sensitivity for monitoring slight mechanical signals(e.g.,respirations and pulses),the capability of CBs for full-range sensing strain signals in human bodies was systematically investigated.