Fabrication Of Foldable Power Paper And Its Application In Chemical Sensing

The medical problem has always been a sensitive“social nerve”that affects thousands ofhouseholds.The problems of difficult,expensive,and tired to see a doctor have become commonplace in life.The resolution of this issue is directly related to the immediate interests of1.3 billion people.In common,the diagnosis in hospitals often relies on the operation of large-scale equipment and professionals,limiting their popularity in the home.How to realize rapid and point-of-care diagnosis of diseases has become a major demand for social development.In recent years,emerging mobile and wearable medical products have attracted amounts of attention in the field of real-time diagnosis.Although smart wearable sensing devices have good market prospects,they still face technological bottlenecks such as low power consumption,complex system integration,and dependence on flexible and high-efficiency energy.For the needs of mobile sensing devices for flexible energy devices,a flexible power paper for self-powered chemical sensing system was fabricated based on fiber paper.Through the development of high-performance paper electrodes and addressable paper electronic switches,controllable output of voltages on paper substrates can be achieved,solving the problem of flexible energy applied to home-style wearable sensing devices,and opening up the new chapter of low-cost,flexible batteries.The establishment of portable self-powered chemical sensing and analysis system based on flexible paper batteries will promote the application of microfluidic paper devices in the real-time detection field.The paper mainly includes the following five parts:In the first chapter,the characteristics and preparation techniques of power paper and lab-on-paper,as well as their application in chemical sensing in recent years were summarized.Besides,the bottlenecks in the development of microfluidic paper chips were proposed.Based on the research foundation of our group in fuel cell and lab-on-paper,the research ideas of this paper were put forwardIn the second chapter,the electrode material as well as conducting interconnections,p-toluenesulfonic acid?p-TSA?doped polypyrrole embedded in-between the cellulose fibers?p-TSA-PPy/cellulose?were obtained by combining in-situ chemical oxidative polymerization with paper microfluidic technique,based on the foldability and liquid self-driving ability of paper.Then,a three-dimensional paper circuit was established based on the principle of origami.In such unique integrated configuration,the utilization of p-TSA-PPy/cellulose network not only dramatically enhanced the horizontal electrical conductivity,but also conquered the issue of vertical electroconductivity,allowing for the top-channel-bottom conductive interconnections.Finally,a flexible fully-integrated self-powered system on paper was demonstrated by incorporating addressable paper circuit switch into potential-tunable foldable power paper.As a proof-of-concept,an all-paper microfluidic analytical platform that integrated paperbased electrochemiluminescence strategy and proposed power paper was constructed with comparable performance.This work greatly improves the understandings of all-paper-based self-powered systems,and presents the significant potential applications of paper-based flexible electronics.In the third chapter,an anti-folding paper-based porous gold electrode with high performance was constructed by taking advantage of the three-dimensional network structure and double-side handleability of paper fibers,which greatly improved the vertical electrical conductivity of paper gold electrode.Furthermore,the microtopography of prepared paper gold electrode were characterized by means of scanning electron microscopy.Then,anti-folding paper circuit and water-resistant conductive paper channel were created by introducing secondary wax printing technique.Flexible power paper was established based on the difference in oxidation potentials between the metal magnesium and the Prussian blue.Then,a low-cost pencil-drawing method applying on the porosity of paper substrate is introduced to overcome the key technical issue of reversible control for fluid and current.The obtained output controllable power paper is provided with intriguing self-charging/recharging properties,and applied to drive the electroploymerization of polypyrrole film and polyaniline network,and electrochemiluminescence images with competitive performance.It is believed that this work shows new insights to the formation of flexible green power and instructive roles for the future design of integrated platform.In the fourth chapter,in view of the developing new promising visible-light-driven metal-free photosensitive material for photoelectrochemical sensing,large-scale two-dimensional?2D?graphite-like carbon nitride?g-C₃N₄?nanosheets with obvious upconversion properties were obtained through a liquid exfoliation route using bulk g-C₃N₄ as precursor.Zn O nanotubes array obtained by corrosion of ZnO nanorods were functionalized by2D g-C₃N₄ nanosheets,and provided as PEC platform showing enhanced PEC activity than the individual materials,which could be ascribed to the appropriate band alignment between the g-C₃N₄ nanosheets and ZnO nanotubes.On the basis of the enhanced PEC activity,a novel PEC biosensing platform was demonstrated to detect carcinoembryonic antigen as a model target analyte using the in situ produced ascorbic acid as electron donator under visible light source irradiation.As expected,excellent assay results were achieved owning to the synergistic effect.Furthermore,benefiting from the inherent attractive properties,the water-soluble ultrathin g-C₃N₄ nanosheets might open a new promising platform for bioimaging.In the fifth chapter,based on the experience of fabrication of flexible power paper and its application in chemical sensing analysis,the design,construction and integration methods of electronic components on paper were summarized.In addition,the structural regulation laws on the inorganic and organic nanomaterials grown in paper were proposed.Nevertheless,research on flexible paper electronic devices is still in the early stages,thus,there are some defects that need to be overcome.In the end,the direction of research work to be further developed is proposed.