Preparation And Application Of Conductive Bacterial Cellulose/polypyrrole Composites

Bacterial Cellulose(BC)has high specific surface area and porosity,good film formation and mechanical properties,excellent degradability and biocompatibility,and has a wide range of applications in fiber-based wearables and pressure sensor components.In this paper,ferric chloride(Fe Cl₃)was used as oxidant to synthesize polypyrrole(PPy)in bacterial cellulose suspension by in-situ polymerization.Then BC/PPy conductive film and composite network structures were constructed by filtration and freeze-drying processes,respectively.The purpose of this research is to expand the range of applications of bacterial cellulose.First,polydopamine(PDA)was used to modify the surface of bacterial cellulose suspension which increases the surface adhesion and dispersion of bacterial cellulose.Based on abvoe,polypyrrole was synthesized by in-situ polymerization with ferric chloride(Fe Cl₃)as oxidant to form BC/PDA/PPy suspension.BC/PDA/PPy film was prepared by using vacuum filtration device to extract and filter quickly the above suspension.The electrochemical performance was tested and the conductivity of BC/PDA/PPy film can reach to 9.6 S/cm.After 32 times bending,the film can still maintain good conductivity.According to CV and EIS curves,it showed that the charge and discharge process of BC/PDA/PPy film was reversible.PDMS was used to assemble the BC/PDA/PPy film and its real-time resistance changed when monitoring finger movement was tested,which showed that the film had good sensitivity.In order to expand the range of applications of bacterial cellulose,BC was cross-linked with polyethylene glycol diacrylate(PEGDA)as cross-linking agent.The BC/PEGDA composite network structures were prepared by freeze-drying technology.Based on above,the conductive composite network structures of BC/PEGDA/PPy were synthesized by in-situ polymerization using Fe Cl₃as oxidant.The effect of different mass fractions of PEGDA on cross-linking degree,composite network structures,mechanical properties,porosity and electrical conductivity were explored.The composite network structures have good mechanical strength when the amount of PEGDA is 4 wt%,and the deformation ability conductivity was 3.59 S/cm.According to CV and EIS curves,it shows that the charge-discharge process of BC/PEGDA/PPy was reversible.The composite network structures could produce different stable real-time resistance changes under different pressures.The higher the pressure,the higher the rate of real-time resistance changes.When the finger pressed on the surface of composite network structures,the oscilloscope could produce regular fluctuations with higher sensitivity.In order to simplify the preparation method of the composite network structures and improve the compression recovery performance of the structure,chitosan(CH)was used as the second component.BC/CH composite network structure was prepared by using the form of physical doping through the freeze-drying technology.Based on above,the conductive composite network structures of BC/CH/PPy were synthesized by in-situ polymerization using Fe Cl₃as oxidant.The differences in mechanical properties,porosity and electrical conductivity of the composite network structures formed by BC and CH with different quantities were explored.For comprehensive analysis,the composite network structures with BC:CH=1:1 were selected for subsequent tests.According to CV and EIS curves,it shows that the charge-discharge process of BC/CH/PPy was reversible.The BC/CH/PPy will produce different stable real-time resistance changes under different pressures.The higher the pressure,the higher the rate of real-time resistance changes.When the finger pressed on the surface of composite network structures,the oscilloscope could produce regular fluctuations with higher sensitivity.