8.8.2 Dynamic properties of colloids (3 )Sedimentation and sedimentation equilibrium Heights needed for half-change of concentration he gravitational force exerting on each particle: systems Particle diameter △h 4 r/nm (0-P0)g 0.27 skI Highly dispersed 1.86 2.15m Au SOl Micro-dispersed 8.53 2.5cm InC LI Au sol (p-p°)(h2-h1)g RT Coarsely dispersed 186 0.2m uSo」 Altitude distribution Brownian motion is one of the important reasons for the stability of colloidal systemThe gravitational force exerting on each particle: f g r ( )g 3 4 0 3 =   −  g d f = f h h g RT LV c c ln ( )( ) 2 1 0 2 1 =  −  − Altitude distribution systems Particle diameter r / nm h O2 0.27 5 km Highly dispersed Au sol 1.86 2.15 m Micro-dispersed Au sol 8.53 2.5 cm Coarsely dispersed Au sol 186 0.2 m Heights needed for half-change of concentration Brownian motion is one of the important reasons for the stability of colloidal system. (3) Sedimentation and sedimentation equilibrium 8.8.2 Dynamic properties of colloids