Green chemistry application to intermolecular forces

1. Practical Application of Intermolecular Forces

A Study of Adhesives
By Babi Hijau (Photo taken by own) [Public
domain], via Wikimedia Commons

2. Intermolecular Forces

• Forces between molecules
–
–
–
–
Permanent dipoles
Induced dipoles
van der Waals or London Dispersion forces
Hydrogen bonds

3. Applications

• Determines various physical properties of a
molecular solid
– Melting point
– Boiling point
– Vapor pressure
• Adhesive force of glue

4. An adhesive is a substance that sticks to the surface of an object such that two surfaces become bonded.

By Amirreza Saharkhiz (Own work) [CC BY-SA 3.0
(http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia
Commons

5. The adhesive will “wet” or cover the substrate, when the Intermolecular forces between the glue and the substrate are stronger than the Intermolecular forces between the glue and glue.

By Mk2010 (Own work) [CC BY-SA 3.0
(http://creativecommons.org/licenses/by-sa/3.0) or
GFDL (http://www.gnu.org/copyleft/fdl.html)], via
Wikimedia Commons
The adhesive will
“wet” or cover the
substrate, when the
Intermolecular forces
between the glue and
the substrate are
stronger than the
Intermolecular forces
between the glue and
glue.

6. For an adhesive to wet a surface, the adhesive should have a lower surface tension, than the solid’s surface energy (or critical surface tension),

By MesserWoland (own work created in Inkscape) [GFDL
(http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0
(http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA
2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/2.5-2.01.0)], via Wikimedia Commons

7. Adhesive Curing

Theilr’s Flickr account –
Creative Commons
Attribution
Once the adhesive is applied to the
substrate, it will begin to cure, or form a
permanent bond
Different Adhesives have different
mechanisms in which the curing takes place

8. So HOW do glues compare?

In the following lab you
will investigate the
differences in the
adhesive ability of some
different types of glues
By Selena Wilke (Own work) [Public domain], via
Wikimedia Commons