Study On The Piezoelectric Properties Of Polyacrylonitrile Nanofiber Membranes

PAN has two molecular conformations,a planar sawtooth conformation and a helical rod conformation.It is widely used in filter materials and adsorbent materials in daily life.Recent studies have found that it has a high dipole moment(3.5D)and has the potential to be a polymer piezoelectric material.Therefore,PAN was used as raw material to study its molecular conformation and piezoelectric properties.In the second chapter,7%,9%,11%,13%,15%concentration(wt%)of PAN nanofiber membranes were first prepared,and the piezoelectric properties of the nanofiber membranes were compared.It was found that the piezoelectricity of PAN nanofiber membranes prepared at different concentrations was different.When the concentration of PAN was 11%,the piezoelectricity reached a maximum.In the range of 7%and 11%,as the concentration of PAN increases,the planar sawtooth conformation gradually increases,and the piezoelectric performance also increases.In the range of 11%to 15%,as the PAN concentration increases,the planar sawtooth conformation gradually decreases,and the piezoelectric performance is also relatively reduced.Then,PAN nanofiber membranes with different rotation speeds were prepared,and the piezoelectric properties of the nanofiber membranes were analyzed and compared.It is found that the piezoelectric properties of PAN nanofiber membranes obtained at different rotational speeds are different.The piezoelectric properties of PAN nanofiber membranes are best at 1200r/min,and the planar sawtooth conformation is more.In the third chapter,MWCNT/PAN composite nanofiber membranes with different concentrations(wt%)of carbon nanotubes and 10%PAN nanofiber membranes were prepared and their nanofiber membranes were analyzed and compared.The addition of carbon nanotubes reduced the piezoelectric properties of the PAN nanofiber membrane and reduced the planar sawtooth conformation.When the concentration of carbon nanotubes was 0.25%,the piezoelectric properties the best,and the planar sawtooth conformation content is relatively high.The addition of carbon nanotubes had little effect on the thermal properties of PAN nanofiber membranes,and the mechanical properties of PAN nanofiber membranes were relatively large,which improved the mechanical properties of PAN nanofiber membranes.The fourth chapter analyzed the static elimination of PAN nanofiber membrane and changes the test frequency,stroke and membrane area test method.The PAN nanofiber membrane was treated with isopropyl alcohol to eliminate its static electricity to obtain its stable voltage and current output.Through the test of its frequency,duration and membrane area,the voltage and current output of PAN nanofiber membrane was proportional to the frequency,stroke and membrane area within a certain range.These provide some reference value for future research.