Dynamic properties of concentrated suspensions of charged polystyrene spheres

• Published in: Biophysical chemistry Vol. 11; no. 3; pp. 411 - 416
• Main Authors: Mitaku, Shigeki, Ohtsuki, Toshiya, Kishimoto, Akihiko, Okano, Koji
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.1980
• ISSN: 0301-4622; 1873-4200
• DOI: 10.1016/0301-4622(80)87015-3

Ordered structure formation of charged polystyrene spheres was studied by measuring the order-disorder phase diagrams as well as the mechanical properties. The phase diagrams indicate that the ordering of polystyrene spheres obeys Lindemann's law of crystal melting, in which the Lindemann's parameter is about 5%. The rigidity of about 10 3 dyn/cm 2 was observed in the ordered suspension of polystyrene spheres as measured by a torsional quartz crystal method. The steady flow properties of suspensions of polystyrene spheres showed a remarkable change from a Bingham body to a Newtonian liquid at the transition point. The limit of elasticity in the ordered phase was about 1 dyn/cm 2. The viscosity in the disordered phase was well explained by the free volume theory of liquids. It is concluded from these facts that the ordered phase of polystyrene spheres is a real “crystal” whereas the disordered phase is a “liquid”. Properties of ordered structures in biological systems are also discussed.