Monomers &

PolymersBiopolymers• RNA and DNA• Cellulose• Polypeptides• Proteins• Starches• Latex

Synthetic Polymers• Rubber• Plastic• Nylon• Teflon• Glue• Huge in Materials Science

Subatomic Particles

• Protons• Neutrons• Electrons• Lots More!

CHEMISTRY: the study of matter and its properties.

Atoms

• Periodic Table• Smallest unit of an

element.

Molecules

• Two or more atoms held together by chemical bonds.

• Smallest unit of a compound possible.

Make

Up

Make

Up

e-

p+

79Au

Gold197

H H

O

Monomers

• Small molecules which bind to other similar small molecules.

• Mono = one

A B

Polymers

• A combination of monomers• A large molecule with repeating

subunits

A B A B A B A B A B

Crosslinking

• The process of joining two molecules together with a chemical bond.

• Two polymer chains can link together

C D C D C D C D C D

A B A B A B A B A B

E E E E

Methylene(CH2) is perhaps the simplest monomer.

Methylene combines with itself to form ethylene

Methylene forms a polymer chain

PVA glue contains, among other things, Polyvinyl Alcohol (polyethenol) which has the molecular structure pictured to the left(C2H4O). This monomer can combine with itself into longer, more complex chains or units called polymers!

A polyvinyl alcohol polymer chain to the right: A polymer is a combination of monomers

Borax powder forms the Borate ion when in solution. It has a molecular structure as shown on the left.

The Borate ion joins or crosslink’s separate polyvinyl alcohol polymer chains into one molecule. The Borate ion is making weak bonds with the OH groups (hydrogen bonds!)

• White glue (polyvinyl acetate) is an example of a polymer—it is made of long chains of polyvinyl alcohol molecules.

• Glue chains can slide past one another “fairly” easily, enabling the glue to be poured from the bottle.

• Glue is more viscous than water, however. It is thicker and harder to pour. Glue must be squeezed from the bottle. This is because the glue chains are already are very large and are somewhat attracted to one another (glue molecules are larger and bulkier than water molecules).

• The addition of borax causes the the large molecular chains to crosslink which means they can not slide past one another as freely.

• The borate ions link the big glue molecules to each other which results in even bigger molecules. These extremely large, cross-linked molecules find it very difficult to slide past one another.

• The final result is a tangled mass that we know and love as slime.