W. Richard Bowen and Nidal Hilal 4

GREEk SyMBOLS 73
Z cl � Number of bound chloride ions �
Z COO ˆ Charge number due to ionisation of carboxyl
groups
Z T Total charge number of BSA molecule �
GREEk SyMbolS
� Hydrodynamic radius (� a � d) m
� 0i Electronic polarisability of molecule i m 3
� Activity coefficient of chloride ion in NaCl solution �
� i Reduced surface potential i �
� ik Interfacial energy between components i and k J m �2
ε 0 Permittivity of vacuum (8.854 � 10) C V �1 m �1
ε ri Dielectric constant of component i �
� Zeta potential V
�i Number of atoms per unit volume of the interacting
material
m�3 � Distance parameter in Lennard-Jones equation m
�d Charge density of diffuse double layer C m�2 �m Molecular diameter m
�o Surface charge density C m�2 � Debye–Hückel parameter m�1 � Characteristic wavelength m
�c Correction applied to Stoke’s law �
� Viscosity of fluid N s m�2 �R Ratio of the elastic deformation to the applied load and
adhesion to the effective range of the surface forces
� Electrostatic potential V
�� Electrostatic potential at outer cell boundary V
�d Electrostatic potential at OHP (� zeta potential) V
�o Electrostatic potential at particle surface V
wi Characteristic frequency of electromagnetic radiation rad s�1 wUV UV characteristic frequency of electromagnetic
radiation
rad s�1 ε Depth of the potential energy well J
�