| Tetra-needle-like zinc oxide whisker(T-ZnOW)is one kind of multifunctional inorganic material with uniform three-dimensional structure.It has many characteristics such as asymmetric crystal configuration,nontoxic and so on.Especially,as an outstanding semiconductor material,it could touch each other to form a conductive channel after dispersed in polymer materials,and the electric charge accumulating on the surface of polymer could be discharged through ZnO whisker channel.Compared with other antistatic agents,T-ZnOW has advantages of light colour,high strength and durability.Therefore, T-ZnOW has attracted attention for their unique properties and application in plastic,fiber and so on.Resistivity of T-ZnOW is up to 108Ω·cm,and its application in antistatic polymer was limited.In this work,highly conductive tetra-needle-like zinc oxide whisker was prepared by solid state method and surface modification.The results showed as follows:Highly conductive T-ZnOW was prepared by solid state method and surface modification with T-ZnOW and metal salt as raw materials.The effects of solvents,dopant concentration,annealing temperature, annealing time and Al source on the resistivity and crystal shape of T-ZnOW were investigated.The optional conditions of preparation were obtained.Conductive T-ZnOW was characterized by chemical analysis,. XRD,SEM,and FT-IR:The resistivity of Al-doped T-ZnOW was decreased from 108Ω·cm to 102Ω·cm.SEM results indicated that the tetra-needle-like structure of T-ZnOW could be well retained during doping process with C9H21AlO3 as dopant.The effects of Al sources on the shape of T-ZnOW were in order of Al2(SO4)3＞AlCl3＞C9H21AlO3.Integrating with the results of FT-IR analysis and the electrical measurement,it was concluded that the formation of[AlO4]units in Al-doped T-ZnOW resulted in low resistivity. It was found the electric resistivity of T-ZnOW was also dominated by annealing temperature and dopant concentration and so on.After optimizing the technologic conditions,the results showed that the optional conditions were using ethanol as solvent,C9H21AlO3 as Al source, Al concentration of 7at.%,the post heat cheating temperature was 900℃, annealing temperature was 700℃and annealing time was 1 h,the lowest resistivity of T-ZnOW was 6.9×102Ω·cm.The resistivity of Zn-coated T-ZnOW was decreased from 108Ω·cm to 101Ω·cm,and the shape of T-ZnOW was retained integrated.The colour of Zn-coated T-ZnOW was dark.After optimizing the technologic conditions,the results showed that the optional conditions were coated with 10wt%Zn powder,using ethanol as solvent,C9H21AlO3 as Al source, Al concentration of 2at.%,the annealing temperature was 700℃and annealing time was 1 h,the lowest resistivity of T-ZnOW was 22.6Ω·cm.When doped with Sb ion or coated with SnO2,the resistivity of T-ZnOW was decreased by 4 orders of magnitude and obtained light colour powder.The volume resistivity of the epoxy resin composite decreased in four to five orders of magnitude,when added 2.5-3wt.%T-ZnOW.
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