defination of vander waals force, type of

1. Vander Waals Forces and Its
Significance
By -: Lovnish Thakur(IBT-1ST SEM)
Enrollment No. -: ASU2014010100099
Presentation-:U4P1
Course-: Chemistry for biologist(102)

2. Vander Waals force
• It is the sum of the
attractive or repulsive
forces between molecules.
• These were named after -:
Johannes Diderik van der
Waals

3. Its main characteristics are:-
 They are weaker than normal covalent ionic bonds.
 Van der Waals forces are additive and cannot be saturated.
 They have no directional characteristic.
 They are all short - range forces and hence only
interactions between nearest need to be considered
instead of all the particles. The greater is the attraction if
the molecules are closer due to Van der Waals forces.
 Van der Waals forces are independent of temperature
except dipole - dipole interactions.

4. • These includes-:
• force between two permanent dipoles (Keesom
force)
• force between a permanent dipole and a
corresponding induced dipole (Debye force)
• force between two instantaneously induced
dipoles (London dispersion force).

5. Dipole-Dipole
• Two polar molecules align so that d+ and
d- are matched (electrostatic attraction).
• Ex: ethane (C2H6) vs. fluromethane (CH3F)
www.bbc.co.uk

6. Dipole-Induced Dipole
A dipole can induce (cause) a temporary dipole
to form in a non-polar molecule
The molecules then line up to match d+ and d-charges
www.meta-synthesis.com

7. Dispersion Forces
A temporary dipole forms in a non-polar
molecule which leads to a temporary dipole to
form in another non-polar molecule.
Dispersion is the only intermolecular attraction
that occur between non-polar molecules
sciencejl.blogspot.com

8. SIGNIFICANCE

9. In Protein folding
www.intechopen.com
Vander waals interaction is
the another important
bonding type that helps
stabilizing the protein
structure. In the coiled-coil
protein, there is interaction
between side chain in alpha
helix. If these repeating
residues are hydrophobic,
such as leucine, van der waals
interaction will be formed to
stabilize this protein
structure.

10. Graphenes Bonding Forces in Graphite
Weak forces between
graphenes suggest
that they are the van
der Waals Forces.

11. In polymer formation
• Many polymeric chain are cross linked by vander
waals force and get stable.
www.m2polymer.com

12. Used by some animal
• Gecko lizard use these forces to climb on the
walls.
• Some other animal use animal to walk on
water.
dieffi.deviantart.com en.wikipedia.org

13. In modern technology
In May 2014, DARPA demonstrated the latest
iteration of its Geckskin by having a 100kg
researcher (saddled with 20kg of recording
gear) scale an 8m tall glass wall using only two
climbing paddles. Tests are ongoing, but
DARPA hopes one day to make the technology
available for military use, giving soldiers Spider
Man-like abilities in urban combat

14. www.wired.com

15. References
http://en.wikibooks.org/wiki/Structural_Biochemistry/Chemical_
Bonding/Van_der_Waals_interaction
antoine.frostburg.edu/chem/senese/.../h-bonding-vs-london-forces.
shtml
en.wikipedia.org/wiki/Van_der_Waals_force
chemwiki.ucdavis.edu › ... › Intermolecular Forces
przyrbwn.icm.edu.pl/APP/PDF/112/a112z308.pdf