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奈米科技概論期末報告 Sub-micron particles manipulation with dielectrophoretic force. 鍾政哲 Q28971033. _. _. _. _. A. +. m. +. +. +. +. +. +. +. _. m. B. _. _. Theory of Dielectrophoretic Force. F DEP = 2 p e m r 3 Re[ f CM ( w ) ] E 2
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奈米科技概論期末報告Sub-micron particles manipulation with dielectrophoretic force 鍾政哲 Q28971033
_ _ _ _ A + m + + + + + + + _ m B _ _ Theory of Dielectrophoretic Force FDEP = 2 pem r3 Re[ fCM (w)] E2 r: particle radius, fCM(w)= (ep*– em* / ep*+ 2em*): Clausius-Mossitti factor e*= e - j s/w, s: conductivity,e: permittivity, w= 2pf, f: frequency Re[fCM()] > 0: positive DEP Re[fCM()] < 0: negative DEP |ep*| < |em*| |ep*| > |em*| + At high frequency: (ep- em), permittivity dominated At low frequency: (sp-sm), conductivity dominated Medium - Plate electrode
Polynomial Electrode - + - 500 nm Dia. Latex bead in DI water An AC electric field of 20 Vp-p and 500 kHz ~10 MHz was applied + Simulation of electric field ITO electrode
+ pDEP Re[K(w)] nDEP - 100 101 102 103 104 105 Electric field frequency Cross-over frequency of 500 nm Dia. Latex beads Re[K(w)]:
pDEP → nDEP Particle: 500 nm latex beads, medium: DI water, AC condition: 20 Vp-p, 500 kHz→5MHz
Dipole moments → Particle chains - - - - - - - - - Application – The orientation of sub-micron particles + - + - + - + - + - + - + - + - + - + - + - + - + + + + + + + + +
0 s 30 s 60 s 90 s 120 s Tweezer Electrode Arrangement of carbon nanotube
Conclusion • The orientation, concentration and arrangement of sub-micron particles can be manipulated dieletrophoresis with functional electrode designs. • The carbon nanotube also can be manipulated with dielectrophoresis, because the aspect ratio of nanotube is high. The dipole moment of nanotube can be easily induced by electric field.