Research On The Preparation And Properties Of Molybdenum Disulfide/Polyvinylidene Fluoride Composites

Piezoelectric composites,combining the high piezoelectirc properties of inorginic materials and good flexibility,processability of polymer,are great potential intelligent materials.A lot of reasearches have been studied on 0-3 type piezocomposites.However,the research progress demonstrated that when the content of ceramic reached a high value,the piezoelectric properties could be promoted,which would make the materials be fragile.The recent research has discovered that when the thickness of molybdenum disulfide?MoS₂?decreased to monolayer,it would show strongly piezoelectric.To overcome the disadvantage of 0-3 type piezocomposites,this paper studied the influence of two-dimensional MoS₂ on the piezoelectric properties of 2-3 type piezocomposites.Solution-Processed was used to prepare a series of MoS₂/PVDF composites.At the same time,the influence of the content of MoS₂ on the dielectric property and piezoelectric property of the composites was studied.?1?MoS₂ power was mixed with PVDF by solution blending and hot press molding.The structure and morphology of MoS₂/PVDF were characterized by XRD?FTIR and SEM.The results showed that MoS₂ was well dispersed in PVDF and the presence of MoS₂ could benefit the increase of?phase.The dielectric measurement showed that when the content of MoS₂ was up to wt.30%,the dielectric constant would be 50,which was 5 times larger than that of pure PVDF.However,with the increase of dielectric constant,the dielectric loss was also increased.The piezoelectric coefficient d₃₃ of MoS₂/PVDF composite was 9 pC/N with wt.2%MoS₂,a slight increase compared to the pure component.The mechanical performance indicated that MoS₂ was a good toughening agent.?2?The liquid exfoliated technique was introduced to prepare high yield dispersions of single-layer MoS₂.The concentration of MoS₂ dispersion was estimated by UV-Vis spectra.TEM and AFM revealed that the prepared MoS₂nanosheets was mainly monolayer.In addition,as with bulk MoS₂,MoS₂ nanosheets also played the role of toughening agent and could also benefit the increase of?phase.The increase in the dielectric and piezoelectric properties of MoS₂ nanosheets/PVDF composites was attributed to the increase of the interfacial area.The piezoelectric coefficient d₃₃ of MoS₂ nanosheets/PVDF composite was up to 26 pC/N with wt.1%MoS₂ nanosheets,which was four times larger than pure PVDF.?3?PVP was a kind of coating layer to prevent the MoS₂ nanosheets to stack.The exsitence of PVP improved the interface of MoS₂ nanosheets@PVP/PVDF composites and promoted the transformation of?to?phase.The dielectric and piezoelectric characterization showed that dielectric constant,dielectric loss and conductivity varing with the frequency kept the same trend with pure PVDF,which demonstrated MoS₂ nanosheets were completely coated by PVP.The piezoelectric coefficient d₃₃ of MoS₂ nanosheets@PVP/PVDF composite was up to 36 pC/N with wt.5%MoS₂ nanosheets@PVP.