Physical Chemistry of Foods

TABLE3.1 Overview of Possible Interaction Forces Between Atoms, Molecules, and Particles

Type of
interaction

Energy

involved,

ðkBTÞ

Working

range (nm)

Dependence

of energy

on distancea

Fixed

direction

Attraction or

repulsion Additive

Hard-core Very large 0.1 r
^12 No R
Covalent 200 0.2 Complicated Yes A No
Coulomb 200 b 20 c r
^1 No A or R Yes
Charge-dipole Up to 50b 0.3c r
^4 No A No
van der Waals 1 1–20 r
^6
h
^1 No A Yes
Hydrogen bond 10 0.2 r
^2 Yesd A
Solvation ‘‘Weak’’ Up to 2 expð
h=xÞ No R (or A) No
Hydrophobicc 5 e Up to 2 expð
h=xÞ No A f

Quantities given are examples.
aris from the center of the atom,hfrom the surface.
bIn air or vacuum.
cIn aqueous solutions.
dSome freedom in direction, e.g., 20 degrees.
eFree energy.
fProportional to hydrophobic surface area.