Polymer Coatings and Adhesive Joints

Adhesion are...

• ...the forces that occur between different materials

• ...the forces that occur between identical materials

• ...the forces that occur between two contact surfaces

• ...the forces that occur inside materials

The universal adhesion theory can be used to determine the intermolecular forces involved.

• True

• False

How can the wettability of a surface be quantified?

• Zeta potential analysis

• Contact angle measurement

• Tensile shear test

• Surface treatment

Rule of thumb: "Proper" wetting is achieved when the contact angle is <30°.

• True

• False

What is the surface free energy?

• The gravitational force acting on a surface when it is tilted at a 45-degree angle.

• The electromagnetic energy required to create an electric field across the surface.

• The amount of kinetic energy required to move a surface horizontally by 1 meter.

• The mechanical work to enlarge a surface by 1 cm2 by breaking bonds

What is a Van der Waals force?

• Strong electromagnetic forces over long distances

• Strong covalent bonds between atoms.

• Temporary dipoles due to fluctuating electrons

• Atom donates electrons to another atom

What are the two basic mechanisms of adhesion referred to?

• Mechanical & specific adhesion

• Van der Waals forces and crystallization

• Hydrophobic interactions and capillary action

• Electrostatic attraction and diffusion bonding

Permanent dipoles are formed by what?

• Covalent bond atoms with very different electronegativities

• The complete transfer of electrons from one atom to another

• The temporary fluctuations in the electron cloud

• The absorption of photons causing electrons to move to a higher energy level

What are the requirements for wetting surfaces?

Adhesives are primarily classified according to:

• degradation mechanism

• curing mechanism

• texture while application

• origin