Preparation And Electrorheological Characteristics Of Composite Of Graphene-like Molybdenum Disulfide/Polystyrene

Electrorheological?ER?fluids,its liquidity could be controlled by electric field,and its form could turn from liquid to solid under electric field,which are regarded as an new intelligent material that have tremendous application prospects in the area of engineering machinery.Considerable researches on electrorheological?ER?fluids composed of layered graphene or graphene oxide combined with conducting polymer or other organic materials have been reported over the past few years,such as GO-PS?GO-TiO2 composites and so on.However,the ER properties of those composites have a large space of promotion.At the same time,graphene materials used in ER materials have not obvious controllability due to it has not band gap,and only a few studies research about factors influencing ER properties have been reported so far.In this paper,we synthesized different MoS₂/PS core-shell structured nanocomposite successfully using the PS that could be modified easily coated with semiconductive structured graphene-like MoS₂ that has high band gap after surface modification of PS.And we made these core-shell structured nanocomposites as electrorheological?ER?polarizable particles with different kinds.Then we studied some factors of electric field strength,particle size,especially,proportion of MoS₂ to PS and groups on the surface of PS and structures on the ER properties probably influencing the performance of ER and analyzed the influencing mechanism,aiming to prepare an novel ER material that has better ER properties.The detailed contents are mainly engaged in the following aspects.We prepared PS particles with different size of 0.5,1,3,5,7 um by different methods:emulsion polymerization,soap-free emulsion polymerization,dispersion polymerization,and have modified 5 um size of PS.We synthesized different kind of the core-shell structured MoS₂/PS nanocomposite successfully through 1 g PS coated with 250,500,750,1000 ml MoS₂ disperse solution with the help of cationic surfactant of hexadecyl trimethyl ammonium bromide?CTAB?,respectively.And we studied the ER properties of different particles,which are?1?particles with same content of MoS₂ and different size of PS,?2?particles with different content of MoS₂ and same size of PS and?3?particles with same content of MoS₂ and different group on the surface of PS.We also studied different coated structured MoS₂/PS according to the result of experiments above,which are?1?particles prepared by in-situ synthesis instead of physical electrostatic attraction,?2?particles prepared by crosslink-PS coated with MoS₂ compared with non-crosslink-PS,and?3?particles connected by dimeric surfactant instead of CTAB.The results are as follows.?1?The large sized particles could produce more polarizable electrons which make the large sized particles behave better ER property than small sized particles.However,the increase gradient of ER property will be decline when the size of particles reach 1um of micron level,which is due to the capability of collecting electrons is relate to the MoS₂,the content MoS₂ on the surface of particle will decline when the size of PS increase,limit the ER property when increase the size of particles.?2?The content of MoS₂ on same sized PS increase will make the ability of collecting polarizable electrons increase,which fortify the entire ER property of materials.What interesting is the ER property will appear an abrupt increase when change the content of MoS₂ under different electric field in the ER studies.The MoS₂/PS particles with different MoS₂ will appear a optimal response to different electric field,which illustrate the MoS₂ with semi-conductor structure could express a better ER property compared GO.?3?We prepared ER fluid composed of MoS₂/PS particles with same content MoS₂ and modified PS with different group,such as sulfonyl,carboxyl,amino and nitryl on the surface of PS in the same situation.We found that these four group have different polarizability,which could make the MoS₂/PS produce more polarizable electrons,and found that the increase is relate to the polarizability of these four group.The polarizability of four group:sulfonyl>carboxyl>amino>nitryl,and relative ER property:MoS₂/sulfonyl PS>MoS₂/carboxyl PS>MoS₂/amino PS>MoS₂/nitryl PS,which illustrate that the ER property is relate the polarizability of materials.?4?The PS modified by dimeric surfactant coated with the same content of MoS₂ appear better ER property compared the PS modified by CTAB;The crosslink PS coated with MoS₂ appear better ER property compared pure PS;The core-shell structured particle prepared by directly producing MoS₂ on PS appear better ER property compared physical treatment of coated MoS₂.