Dispersion system 1 Dispersion system One or several

Dispersion system

1. Dispersion system: One or several substances disperse in another substance serving as medium. Domain: dispersed phase Continuous phase: dispersion medium

1. 2 Classification of dispersion systems According to the size of dispersed phase r/m Atom number name Phase number uniformity < 10 -9 < 103 Molecular dispersion Single phase uniform 10 -7~10 -9 103~109 Colloidal dispersion multiphase uniform 10 -7~10 -4 > 109 Coarse dispersion multiphase nonuniform

1. 2 Classification of dispersion system according to state Dispersion medium Dispersed phase Gas liquid Liquid aerosol Fog, liquid sprays Solid aerosol Smoke, dust Gas foam Whipped cream Liquid Emulsion Milk solid sol paint, mud gas solid foam expanded PS liquid gel jellies, opal solid Solid suspension colored glass smoky crystal liquid solid name Examples

1. 2 Classification of colloids --- according to dispersion state Lyophilic sols: The colloidal particles interact strongly with the dispersion medium. Solution of macromolecules (not “true” solution) Lyophobic sols: The colloidal particles and the dispersion medium has no tendency to interact. Fe(OH)3 sol

1. 3 What is colloids? 1862, Graham: samples Diffusion Semi-permeable membrane Crystalloids Salt, sugar Rapid Permeable Colloids Protein, Fe(OH)3 slow Non-permeable Fundamental concepts Colloids, sol, gel, peptization, dialysis.

diameter precipitation sol 1907, Banmap. H gel 1908, Weimarn: Ba(CNS)2 + Mg. SO 4: concentration 10 -4 ~ 10 -5 mol dm-3, sol; 10 -2 ~ 10 -1 mol dm-3, precipitation, crystal, 2~3 mol dm-3, gel