Abstract: We addressed the dispersion of Se-nanoparticles,an advanced antibacterial material and synthesized via chemical route.The influence of the mono-surfactants,including CTAB,PVP,PEG-2000 and Span80,on the stability of dispersion/suspension of Se-nanoparticles in ethylene glycol was investigated.The results show that the composite surfactants outperform any mono-surfactant.To be specific,CTAB/PVP(or PEG-2000) composite dispersants,mixed with optimal ratio,dispersed the Se-nanoparticles better than any mono-dispersant did.For instance,when it comes to nano-particle dispersion,the CTAB/PVP composites were 105% more effective than that of the best dispersant CTAB.The optimized dispersion conditions were suggested to include:a pH value of 6,a composites of 3%(wt)CTAB and 3%PVP,a dispersion time for 10 min.Stored in air for 60 d,the sedimentation rate was 0.7%.PVP,PEG-2000 and Span80 were chemisorbed and CTAB was physically adsorbed on Se-nanoparticle surfaces.