colloids-general

“kólla”-comes Greek word meaning ‘glue’.

“iod”-like First coined 1605 < chemist < chymist

 < Latin alchimista < Arabic الكيمياء (al-kīmiya’) < article  ال-  (al-) + Ancient Greek χυμεία (khumeia, “art of alloying metals”) < χύμα (khuma, “fluid”)< χυμός (khumos, “juice”) < χέω (kheō, “I pour”).

Thomas Graham (1805-1869)

Glasgow, Scotland

Colloid solution Colloid system

Colloid Colloid chemistry Colloid science

1. Selmi2. Graham 3. Tyndall

Group Diameter a (m) Dispersion D=1/a (m-1)

1. Suspension >10-7 >107

2. Colloid =10-7-10-9 =107-109

3. Solution <10-9 <109

1

2,10 VS

S

S1,2-interface area between dispersed (1) and continuous (2) phase (m2)V1-volume of dispersed phase (m3)

1. By a diameter of particle (а) 2. By a reverse quantity of diameter of particle (1/а)3. By a specific surface area of dispersed phase (S0)

ColloidMicelle, microgel

Polymer

DNA

Protein

Molecule

Atom

Мixture

Molecular mass

Radius

Specific surface area

Colloids can be classified as follows: (by aggregate state)

Medium / Phases

Dispersed phase

Gas Liquid Solid

Continuous medium

Gas

NONE(All gases are

mutually miscible)

Liquid aerosolExamples: fog, mist,

hair sprays

Solid aerosolExamples: smoke,

cloud, air particulates

Liquid

FoamExample:

whipped cream, Shaving cream

EmulsionExamples: milk,

mayonnaise, hand cream

SolExamples:

pigmented ink, blood

Solid

Solid foamExamples: aerogel, styrofoam, pumice

GelExamples: agar,

gelatin, jelly, silicagel, opal

Solid solExample:

cranberry glass

F12=12S12

F12-all excess free energy on interface of phases12-free energy per unit areaS12-all interface area of (1) and (2) phases

m[Fe(OH)3]

Fe+3Fe+3

Fe+3

Fe+3

Fe+3

Fe+3

Fe+3

Fe+3

Fe+3

Cl-Cl- Cl-

Cl-

Cl-Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl-

Cl- Cl-

Cl-

Cl-

Cl-

FeCl3+H2O

1. The solution of all ‘colloid substance’ has property scattering the light. 2. The diffusion of particle is slow effected in colloidal solution. 3. Osmosis pressure is very low and unstable4. Dialysis, The process of separating the particles of colloid from those of

crystalloid, by means of diffusion through a suitable membrane is called dialysis.

5. Coagulation, a process in which dispersed colloidal particles agglomerate.

6. Electrophoresis, it is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field

•Surface phenomenon•Physical and chemical characteristics of the dispersion system•Stabilization of a colloidal dispersion

AgNO3 + KI AgI + KNO3

Thank you for your attention!