Chapter 12 Colloids and macromolecules 12.1 Colloids Dispersed system Dispersed phase Dispersed medium Colloid dispersed system: nm(10 -9 ～ m) Coarse dispersed system: >1 m(10 -6 m)
Colloid or sol (lyophobic colloid) Associated colloid (colloide electrolyte) Macromolecular solution(lyophilic colloid)
Table 12-1Classfication of Dispersed System
preparation Colloid system 1nm ～ 1000nm Solution <0.1nm Agglomeration Disperse Coarse dispersed system >1 m Replacing solvent reaction Physical agglomeration rubbingultrasonic arc
12.2 Properties of Colloid Tyndall Phenomena
Movement Properties of Colloid Fick’s first law of diffusion (1) Diffusion
(2) Sedimentation Sedimentation equilibrium
The electrical double layer2 Stern potential ； Moving potential Thermodynamic potential e ； Closed layer (stern layer) Diffusion layer ee Stern model - - Solid surface Stern section Movable section
– – IHP OHP 固体表面 水化阳离子 特性吸附阴离子 第一层水分子 第二层水分子 (b) 博克里斯模型 – 滑动面
Structure of Colloids AgNO 3 +KI AgI 固相紧密层扩散层 [ （ AgI ） m nAg + （ n-x ） NO 3 ] x+ xNO 3 - 溶液 本体 胶核 胶粒滑动面 胶团
NO 3 - （ AgI ） m Ag +
Stabilization of Colloid Kinetic stabilization Coagulation stabilization 1. The effect of electrolyte on coagulation Coagulation value Schulze--Hardy rule 2. The effect of macromolecules on coagulation bridging effect dehydration effect electric neutralization effect
DLVO theory U R ∝ exp{ - x} U max F C {x}{x} 0 Born repulsion {U}{U} U UA∝UA∝ —Debye parameter
12.3 Macromolecules MacromoleculeM B >1 ～ 10 4 kg.mol -1 Number-average molar mass weight-average molar mass Osmotic Pressure of Macromolecules Solution
Membrane Equilibrium Donnan equilibrium Na + (b) Na + (b ' ) P x- (b ' ) Cl - (b) Na + (b) Na + (b ' ) P 2- (b ' /2) Cl - (b) P 2 - Cl - Na + Na + (b ' +b x ) P 2 - (b ' /2) Cl - (b x ) Na + (b - b x ) Cl - (b - b x )
At equilibrium For dilute solution
Viscosity of Macromolecular Solution Relative viscosity Intrinsic viscosity
12.4 Coarse Dispersed System Emulsion
Emulsifier Demulsification Foam Suspension
表 10-2 胶体分散系统小结