The effect of shear flow on the percolation concentration of fibrillar protein assemblies

• Published in: Journal of rheology (New York : 1978) Vol. 49; no. 2; pp. 355 - 368
• Main Authors: Veerman, C, Sagis, L.M.C, Venema, P, Linden, E. van der
• Format: Journal Article
• Language: English
• Published: Melville, NY Society of Rheology 01.03.2005
• Subjects: birefringence; collagen protein; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; gels; light-scattering; ovalbumin; Physics; Rheology; rheooptical response; rod-like macromolecules; rodlike chains subject; transition-temperatures; viscoelasticity; Percolation; Birefringence; Protein; Proteins; Fibrillar structure; Shear flow
• ISSN: 0148-6055; 1520-8516
• DOI: 10.1122/1.1859793

The objective of this study was to investigate the effect of shear flow on the percolation concentration ( c p ) for solutions of fibrillar protein assemblies. Theoretical calculations were performed to obtain c p versus Peclet number. They were based on a random contact model for rodlike particles, making use of a shear dependent excluded volume per fibril. We found c p to increase with increasing Peclet number. Results of flow birefringence measurements were used to obtain the rotational diffusion coefficient at c p , which enables one to transform the theoretically obtained c p ( Pe ) into a prediction for c p versus shear rate. This prediction was used to fit viscosity measurements as a function of shear rate, near the percolation threshold. A satisfactory fit was found indicating that the percolation threshold, c p , as function of shear rate can be predicted by combining theory and optical measurements.