OMSK STATE MEDICAL
UNIVERSITY
DEPARTMENT OF CHEMISTRY
Colloidal solutions (part 1)
1. Basic concepts. Classification of dispersed
systems.
2. .
3. .
4. Structure of micelles of hydrophobic systems.
5. .
.
Lecturer: Irina Petrovna Stepanova, Doctor of Biological
sciences, professor, head. Department of Chemistry

Colloidal chemistry ("colloid" - from
Greek κόλλα - glue) - science,
studying physical and chemical
properties of heterogeneous
highly dispersed systems and WWII in
solid state and in solution.
Colloidal solution of gold
(exhibit of the Faraday Museum in
Royal Institute)

Thomas Graham (Graham)
English/Scottish chemist
first used the term
"colloidal" to describe
solutions with unusual
properties.
In the development of this science
contributed T. Jung,
P. Laplace, D. Gibbs,
G. Helmholtz, D. Rayleigh
I. Langmuir and others.
T. Graham (1805-1869)

History of the development of colloid chemistry

Nikolai Petrovich Peskov, the founder of the modern
colloid chemistry as a science of
surface phenomena and
dispersed systems.
Introduced the concept of aggregative and
sedimentation
stability of dispersed
systems.
N. P. Peskov (1880-1940)

Medical and biological significance of the topic

Medical and biological significance of the topic

Medical and biological significance of the topic
"Man is a walker
colloid"
I.I. Zhukov

Medical and biological significance of the topic

.

Biomedical
topic meaning
.

Medical and biological significance of the topic

silver solution
a - E. coli cell
b – E.Coli cell exposed to nanoparticles
silver

Bactericidal activity of colloidal silver solution

Medical and biological significance of the topic
The bactericidal activity of colloidal
silver solution
Populations of Listeria
Before processing
After processing
after 1.5 hours

Bionanomaterials

Medical and biological significance of the topic
Bionanomaterials
Reagent
Product
bone cells
on porous silicon
cross-linked enzymes

Nanomaterials

Medical and biological significance of the topic
Nanomaterials
Fast solidifying nanofluid consists of
six molecular rings that form
tubular structures. It is assumed that this
fluid will treat fractures.

Basic concepts

Two
general
sign of dispersed
systems: heterogeneity and dispersion.
A dispersed system (DS) is called
system in which one substance in more
or less fragmented (dispersed)
state evenly distributed in
mass of another substance.

Classification of dispersed systems

The dispersed phase (DP) is a particle, and
dispersion medium (DSM) - a continuous medium in which
there is a fragmented dispersed phase.
The degree of dispersion (D) is determined by the value,
reciprocal particle diameter (d): D = 1 / d.

Disperse systems

dispersed
phase
Dispersive
Wednesday
Surface
phase separation
Example: system - clay in water.
Clay - DF, water - DSr.

Colloidal silver solution

Basic concepts. Classification of dispersed systems

Transverse size of DF particles
For spherical particles, this is the sphere diameter d,
for cubic particles - cube edge L (m-1; cm-1) or
fineness (D
= 1/d, m-1, cm-1).

Forms of the dispersed phase n

Basic concepts. Classification of dispersed systems
Forms of the dispersed phase n

Quantitative characteristics of DF

Basic concepts. Classification of dispersed systems
Quantitative characteristics of DF
The specific surface Syd is the interfacial
area per unit volume
DF (V) or its mass (t).
S beat
S
V
4 r 2 3 6
S beat
6D
43rd
r
3
S beat
6l 2 6
36D
l
l
Specific surface area
Specific surface area
for spherical
particles with radius r
Specific surface area
for cubic
particles with a cube edge

Basic concepts. Classification of dispersed systems
An important property of DS
is the presence of a large
interfacial surface.
Characteristic are
processes taking place on
surface, not inside
phases.

Basic concepts. Classification of dispersed systems
According to the degree of dispersion, dispersed
systems are classified into:
1. Coarsely dispersed (d ˃ 10-5 cm).
2. Colloidal-dispersed (10-7 ˂ d ˂ 10-5
cm).
3. Molecularly dispersed (true
solutions) (d ˂ 10-7 cm).

Basic concepts. Classification of dispersed systems
d ˂ 10-7 cm
True
solution
d: 10-5 - 10-7 cm
Colloidal
solution
d ˃ 10-5 cm
Suspension

Basic concepts. Classification of dispersed systems
Coarse (d ˃ 10-5 cm) - do not pass
through thin paper filters, quickly
settle, visible in a conventional microscope.
Colloidal-dispersed (10-7 ˂ d ˂ 10-5 cm) –
pass through paper filters, but
linger on ultrafilters, visible in
ultramicroscope. Structural unit
is a micelle.
Molecularly dispersed (true solutions)
(d ˂ 10-7 cm) - discrete units in them
are molecules or ions. Are formed
spontaneously.

Classification according to the state of aggregation DSR and DF

DSR DF
System name
G
G
AND
T
-----------Aerosols (Fog)
Aerosols (Dust, smoke)
AND
G
AND
T
Foams, gas emulsions
emulsions
Suspensions, lyosols
T
G
AND
T
Rigid foam
------------Solid sols

Suspensions

Basic concepts. Classification of dispersed systems
Suspensions

emulsions

Basic concepts. Classification of dispersed systems
emulsions

Types of emulsions

Basic concepts. Classification of dispersed systems
Types of emulsions
Oil in water
water in oil
m
Water
Oil

Emulsion particle diameter

Basic concepts. Classification of dispersed systems
Emulsion particle diameter
< 0.5 мм
0.5-1.5mm
1.5-3mm
>3 mm

emulsions

Basic concepts. Classification of dispersed systems
emulsions
Fluid
liquid
viscous
liquid
Gelatinous
liquid

emulsions

Basic concepts. Classification of dispersed systems
emulsions

emulsions

Basic concepts. Classification of dispersed systems
emulsions

Foam

Basic concepts. Classification of dispersed systems
Foam

Spray can

Basic concepts. Classification of dispersed systems
Spray can

Basic concepts. Classification of dispersed systems
If DSR is water, then the systems, respectively
called hydrophobic and hydrophilic.

Sols and gels

Basic concepts. Classification of dispersed systems
Sols and gels
Blood
Tendons

Basic concepts. Classification of dispersed systems
Sol - structureless colloidal
solution in which DF particles are weakly
interact with each other and freely
moving relative to each other
(for example, silver sol - collargol).
In appearance, sols resemble
true solutions.

Basic concepts. Classification of dispersed systems
Gel - structured colloidal
solution in which DP particles are bound
each other into spatial structures
frame types.
In them, colloidal particles are inactive
and can only do
oscillatory movements.
Gels in appearance
jelly-like (for example, toothpaste
Blend-a-med paste).

Basic concepts. Classification of dispersed systems
Sol
(solution)
Gel
(lat. gelate to freeze)

Methods for obtaining colloidal solutions

By way of reaching
colloidal degree
dispersity distinguish
dispersive and
condensation methods
receipt.

Preparation of Lyophobic Colloidal Systems

Dispersion
Substance
oversaturated
true solution
Condensation

Methods for obtaining colloidal solutions

Dispersion methods (from lat. -
grind) - obtaining DF particles by
crushing large particles into more
small.
Apply:
mechanical crushing (using
ball or colloid mills)
ultrasonic (under the influence of
ultrasound)
electric (when using
electrodes).

Dispersion methods
colloidal
mill

Methods for obtaining colloidal solutions

Chemical dispersion -
peptization (consists of
chemical effect on the sediment).

Methods for obtaining colloidal solutions

Condensation methods (from lat. -
enlarge) - obtaining DF particles by
associations of atoms, molecules, ions.
Distinguish between physical and chemical
condensation.

Methods for obtaining colloidal solutions

Physical condensation is a method
solvent replacement.
First prepare the true solution
substances in a volatile solvent (for example,
rosin in alcohol) and added to the liquid,
in which the substance is insoluble (water).
As a result, there is a sharp decrease
solubility and molecules of matter
condense into colloidal particles
sizes.

Methods for obtaining colloidal solutions

Chemical condensation - for
obtaining colloidal solutions
using any reaction
resulting in
sparingly soluble compounds
(reactions of exchange, hydrolysis,
recovery, etc.).

Chemical condensation

In order for the reaction to form
colloidal solution,
meeting at least three conditions:
so that the DF substance is insoluble in
DSR;
so that the rate of nucleation
there were much more DF crystals than
crystal growth rate;
so that one of the starting materials is
taken in excess, that is what is
stabilizer.

Examples of chemical condensation reactions

Reaction
recovery
Ag20 + H2 → 2Ag↓ + H20
Reaction
oxidation
2H2S + S02 → 3S↓ + 2H20
Reaction
hydrolysis
Exchange reaction
100°
FeCl3+ 3H20 → Fe(OH)3 ↓ +
ZHCl
K4 + 2CuCl2 →
Cu2 ↓ + 4KCl

Methods for purification of colloidal solutions

Colloidal solutions, like true ones, are good
filtered through a porous paper filter, but,
unlike true ones, do not pass through
semi-permeable membranes.
Cleaning is based on this
colloidal solutions from
low molecular weight
substances (dialysis,
filtration,
ultracentrifugation).

Dialysis

Methods for purification of colloidal solutions
Dialysis
Dialysis is carried out using a dialyzer device. It consists of 2 vessels,
separated by a semi-permeable membrane
capable of passing molecules and ions
low molecular weight substances.
The solution is poured into the inner vessel
sol, in the outer - water circulates. impurities
are removed through the membrane from the sol solution in
solvent.

Methods for purification of colloidal solutions

Dialyzer: 1 - dialyzable fluid; 2 solvent; 3 - dialysis membrane; 4 agitators

Dialysis

Methods for purification of colloidal solutions
Dialysis

Electrodialysis
Electrodialysis is used to speed up the process.
Dialysable
liquid
distilled
water
distilled
water
Funnel
Solution
impurities
Dialysis
membrane

Electrodialysis

Electrodialysis
apply
for
desalination.
For example,
for
sea ​​desalination
water.

Dialysis

According to the principle of compensatory dialysis
an artificial kidney machine is in operation.
The device is connected to the system
blood circulation of the patient, blood under
pressure flows between two
membranes washed from the outside
saline.
At the same time, toxic substances in the blood
are washed into saline, which contributes to
blood purification.

Dialysis
Before dialysis
In the moment
equilibrium

Methods for purification of colloidal solutions

For purification of colloidal solutions from
coarse particles conduct
filtration through ordinary paper
filters. Coarse particles
stuck in the filter.
To separate DF from DS, use
ultrafiltration. At the same time, they use
special filters that do not pass
colloidal particles or macromolecules.
As a rule, ultrafiltration is carried out
under pressure.

Methods for purification of colloidal solutions

Device for
ultrafiltration: 1
- Buechner funnel;
2 - membrane;
3 - Bunsen flask;
4 - pump

Methods for purification of colloidal solutions

To separate DF particles having
different weight, apply
ultracentrifugation.
In this case, the separation of particles
takes place in a centrifugal field
high accelerations in centrifuges. So,
separate protein fractions.

The structure of a micelle
hydrophobic systems
The structure of colloidal particles and
the appearance of a charge on them explains
micellar theory of colloidal systems.

The structure of a micelle

The charge on colloidal particles arises
either due to ionization of molecules,
located on the surface of a solid
phase, or as a result of an electoral
adsorption on the solid phase.

The structure of a micelle

Consider the second case -
AgI micelle formation in KI.
AgNO3 + KI (excess) = AgI +
KNO3
AgI precipitate is in excess
KI solution.
An excess of electrolyte
the role of a stabilizer.

The structure of a micelle

In this case, a micelle is formed, which has the following
structure:
K
K
K
K
I
I
+
+
K
+
I
+
+
unit
K
I
+
I
AgI I
I
I I
K
+
nucleus
adsorption
layer
granule
micelle
potential-determining ions (p.o.i.)
K
+
K
dense layer of counterions (p.i.)
+
K
+
diffuse layer of counterions

The structure of a micelle

The AgI precipitate is a micelle aggregate.
On a hard crystalline surface
draft in accordance with the Panet-Fajans rule
ions I- will be adsorbed, completing
crystal lattice and informing the particles
negative charge.
Ions - are called potential-determining.

The structure of a micelle

Aggregate and potential-determining ions
form the core of a micelle.
to a negative charge will be
attract counterions K+, forming
dense layer of counterions.
Potential-determining ions and
dense layer counterions together
form an adsorption layer.

The structure of a micelle

Adsorption layer together with the aggregate
make up a granule (or particle). Granule
charged, its charge is determined by the sign and
the magnitude of the charge of the potential-determining
ions.
Part of the counterions not included in
adsorption layer, form a diffuse
layer.
The granule and diffuse layer are
micelle.
Micelle,
so
the way
electrically neutral.

The structure of a micelle.

AgI micelle formula in KI:
x
nucleus
]nI
n
x
K
xK
m)