W. Richard Bowen and Nidal Hilal 4

C Capacitance C V �1
C D Debye interaction constant J m 6
C K Keesom interaction constant J m 6
C L London interaction constant J m 6
C T Interaction constant J m 6
C UV Cauchy Plot parameter �
d Distance to OHP (surface of shear) m
D Surface to surface separation distance m
D jtc Jump-in distance m
D 0 Characteristic decay length m
e Elementary charge (1.602 � 10 �19 ) C
E* Reduced Young’s modulus Pa s �2
E s Young’s modulus for the sphere Pa
E f Young’s modulus for the flat surface Pa
f 0 Force extrapolated to separation distance, D � 0 N
F Force between surfaces/particles N
JKR
FAd DMT
FAd ABBREvIATIONS ANd SyMBOLS 71
Adhesion pull-off force (JKR model) N
Adhesion pull-off force (DMT model) N
FH Hydrodynamic force for a sphere approaching a
plane surface
N
FR Repulsive interparticle force N
FSOL Hydration force N
h Planck’s constant (6.626 � 10 �34 ) m 2 kg s �1
¯h Planck’s constant divided by 2� (6.626 �
10�34 /2�)
J s rad�1 k Boltzmann constant (1.380 � 10�23 ) J K�1 kc Spring constant of the cantilever N m�1 keff Effective spring constant of the cantileversample
system
N m�1 ks Stiffness of the sample N m�1 K Constant in force equation N
Ki Equilibrium constant for ionisation reaction i M
l Correlation length of the orientational ordering
of water molecules
m
n Number of gas molecules mol