Preparation Of Cellulose Paper-based Electrode And Its Application In Electrochemical Sensing

Paper-based electrochemical sensor is a kind of electronic device which is based on cellulose paper.Due to the abundant sources,low-cost,good flexibility and disposable properties of cellulose paper,paper-based electrochemical sensors have been widely used in the fields of environmental pollution,food safety and medical health.At present,the research on paper-based electrochemical sensors mainly focuses on the function of substrate materials and the fabrication of paper electrodes.The fabrication of paper electrode has great influence on the sensitivity and stability of paper based electrochemical sensor.Therefore,the preparation technology of paper electrode has been widely concerned and great progress has been made.The aim of this paper is to develop a technique for the large-scale preparation of high stability composite paper electrodes.Firstly,the traditional paper-making technology was combined with electrochemistry and laser direct writing technology to prepare composite paper electrodes in the large-scale.And the influence of the composite paper-based electrode structure on the preparation process and stability was investigated.Then the possibility of large-scale composite paper electrode as electrochemical sensor was studied.The main research contents are as follow:(1)Firstly,a conductive composite paper was prepared by traditional papermaking technology.Graphene oxide(GO)was assembled with cellulose by electrostatic adsorption of cationic polyacrylamide(CPAM),and then mixed with carbon fiber(CF)to produce conductive composite paper.The physical and electrochemical properties of the conductive composite paper were preliminarily studied.And the application of the composite paper electrode as an electrochemical sensor was researched.The composite paper electrode has excellent electrical conductivity of 1389 S/m.The electrochemical activity of the composite paper electrode can be controlled by the electrochemical reduction time.The stability and repeatability of electrochemical sensing of composite paper electrode were tested by electrochemical method.Finally,composite paper electrodes were used as electrochemical sensors for the sensing of common substance.(2)Compared with the whole conductive composite paper electrode,the patterned paper electrode can integrate the electrochemical sensor on a single paper for practical applications.Therefore,we prepared non-conductive GO/cellulose composite paper by a simple paper making process.And the patterned gold nanoparticles(Au NPs)modified reduced graphene oxide(rGO)/cellulose composite paper electrode was prepared by wet laser direct writing technique in air environment.The reduction of GO and chloro-auric acid by wet laser direct writing and the restricted growth of Au NPs in the pattern region were studied.The prepared composite paper electrode has excellent electrical conductivity and electrochemical conductivity,and its conductivity can reach 1362 S/m.The potential of large-scale composite paper electrodes for electrochemical sensing was studied by friction,water stability and uniformity testing.Finally,the patterned composite paper electrode was prepared as electrochemical sensor,and its potential application prospect was explored.(3)The compact paper structure can simplify the preparation conditions and improve the stability of the patterned paper electrode prepared by laser direct writing.Therefore,we chose smaller bacterial cellulose instead of cellulose pulp to produce a much denser structure of composite paper.Specific operations are as follows: a patterned rGO/bacterial cellulose(BC)composite paper electrode was prepared by paper-making and laser direct writing technology.The unique honeycomb structure of the electrode makes it have good strain sensing performance.Then,the pH responsive polypyrrole/polyaniline was modified on the surface of composite paper electrode by electrodeposition technique,and its application of sweat pH sensor was studied.The mechanism of improving pH sensing performance by microenvironment inside composite paper electrode was studied.Subsequently,the composite paper electrode was assembled into a wearable multifunctional sensor,and its motion monitoring and pH sensing in multiple scenes were preliminarily discussed.(4)On the basis of patterned bacterial cellulose/GO composite paper,we chose lower-cost lignin as a binder and carbon source instead of GO.The hot melt bonding of lignin can make a much denser structure of composite paper,and its higher carbon content can improve the conductivity of paper electrodes.In this research,the Lignin/BC composite paper was prepared by traditional paper-making technology and hot-pressing process.And the effect of hot-pressing process on the morphology and stability of lignin in composite paper was studied.The patterned electrode was prepared on the surface of composite paper by laser direct writing technique,and then the Au NPs were modified by electrodeposition.The biomass based composite paper electrode with high conductivity and electrochemical activity was prepared.Then,the composite paper electrode was used for the sensing of common substances.The feasibility of large-scale preparation of low-cost biomass-based composite paper electrode and its application as paper-based electrochemical sensor was proved.