1. P .K CHOURASIA PRESENTS
SURFACE CHEMISTRY

2. Surface Chemistry
the study of physical and chemical phenomena that occur at the interface of two phases, including solid-liquid interfaces, solid-gas interfaces, solid-vacuum interfaces, and liquid-gas interfaces

3. Phenomena in Surface Chemistry
Wetting, Spreading and Penetration
Foam Breaking in Aqueous Systems
Solubilization
Rheological Effects in Surfactant Phases

4. Assignment-6
Group Presentation G9 : Foam breaking and its application G10 : Solubilization and its application G11 : Rheology and its application
(5 min)

5. Surface Chemistry in Important Technologies
Surface Chemistry in Pharmacy  
Surface Chemistry in Food and Feed  
Surface Chemistry in Detergency 
Surface Chemistry in Agriculture  
Surface and Colloid Chemistry in Photographic Technology  
Surface Chemistry in Paints  
Surface Chemistry of Paper  
Surface Chemistry in the Polymerization of Emulsion  
Colloidal Processing of Ceramics  
Surface Chemistry in Dispersion, Flocculation and Flotation  
Surface Chemistry in the Petroleum Industry

6. Assignment-7 Individual Report
Search from Journals or websites to find
some examples of Surface Chemistry in
Important Technologies
2. Write up a 1 page concise report
in A4 paper.
Report is due on September 15, 2009.
(10 points)

7. Analysis and Characterization in Surface Chemistry
Measuring Equilibrium Surface Tensions  
Measuring Dynamic Surface Tensions  
Measuring Contact Angle
Determining Critical Micelle Concentration   
Measuring Micelle Size and Shape  
Identification of Lyotropic Liquid Crystalline Mesophases  
Characterization of Microemulsion Structure  
Measuring Particle Size by Light Scattering  
Measurement of Electrokinetic Phenomena in Surface Chemistry  
Measuring Interactions between Surfaces  
Measuring the Forces and Stability of Thin-Liquid Films  
Measuring Adsorption

8. 1. Gas-Liquid and Liquid-liquid Interfaces

9. Surface Tension, 
an effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet

10. Surface Tension as a Force
caused by the attraction between the molecules
of the liquid by various intermolecular forces

11. Surface Tension as Surface Excess Free Energy
           ,
     .

12. Determination Methods
Capillary Rise Method
where
h = the height the liquid is lifted,
la = the liquid-air surface tension (J/m² or N/m)
θ = contact angle
ρ = density of liquid (kg/m3)
g = acceleration due to gravity (m/s²)
r = radius of tube (m)

13. The Ring Method
 =
where  =constant
(Du Nouy tensiometer)

14. mg = 3a cos() Pendant Drop Method
 is the surface tension of liquid
 is the contact angle at which a liquid/vapor
interface meets the solid surface.
Contact Angle Goniometer.

15. Surface tension (mN m-1) ofsome liquids
0oC oC 40oC 60oC 80oC 100oC
H2O
Ethanol
Acetone
Toluene
Benzene
Hg (0oC) Ag (970oC) 800
NaCl (1080oC) AgCl (452oC) 125
Intermolecular forces

16. Surface Tension
Directly depends on intermolecular forces in the solution
Inversely depends on temperature
 of metallic liquid > ionic liquid > covalent liquid

17. Liquid in a Vertical Tube
ls = liquid-solid surface tension
la = liquid-air surface tension
= contact angle
Concave
Concave Adhesive>>Cohesive
Convex Adhesive<<Cohesive
Convex

18. Interface Tension and Spreading

19. Spreading Coefficient, S in Water at 20oC
liquid B
n-hexadecane ( ) = Drop on water surface
n-octane ( ) = Spreading
n-octanol ( ) = Spreading against
inpurity

20. predicts the spreading behavior of B on A
Use the following data of
the surface/interface tensions (mN m-1) at 20oC
A B A B AB
H2O C6H
H2O CCl
H2O Hg
H2O C8H15OH
predicts the spreading behavior of B on A

21. Surface Tension of Solution
Substances in solution :
Surface active agent “Surfactant” (<o)
hydrophilic part
hydrophobic part
Surface inactive agent (>o) such as
ionic compounds, acids, bases etc.
                   

22. Surface Tension of Some Alcohols in Water at 20oC

23. Surfactants in solution
                   
Micelle formation
when C > CMC

24. CMC determination
CMC = critical micelle concentration

25. Effect of Temperature on Surface tension
Pure liquid
Surfactant solution T

26. Effect of Concentration on Surface tension
Adsorption On
surface
                   
Gibbs isotherm
 is known as surface concentration (mol/m2)
C is the concentration of the substance in
the bulk solution.
R is the gas constant
T the temperature