Gelation Kinetics—Problems and Prospects

Abstract

This article serves as an overview of past activity in relating the critical percolation (gel) point, p_c, for chemically cross‐linked systems to the gelling behavior of physical gels, especially including those formed from biopolymers. For these, the significant parameters are not p_c but derived quantities such as t_c, the gelation time, C₀ the critical gel concentration, and the equilibrium shear modulus, G. The article also presents a number of new results, both explicitly and implicitly, and the problems in evaluating others are discussed pedagogically. While the relationship between chemical conversion, p, and time, t, is derived quite simply, those between p, G, and polymer concentration C, respectively become increasingly more elaborate. For the most complex systems, for example those involving nucleation and growth of fibrillar systems, it seems difficult to furnish a practically useful analytic solution. Although attempts to simulate such behavior can generate realistic modulus time growth behavior, the number of parameters required tends to frustrate this approach.

Dedicated to Professor John L. Stanford on the occasion of his 60th birthday.

Keywords:

• gelation
• biopolymer gel
• kinetics
• gelation time
• gel modulus

Acknowledgments

This paper is dedicated to Prof. John Stanford on the occasion of his sixtieth birthday. The author is also grateful to Prof. Allan Clark of King's College, London, for important comments on, and additions to this manuscript.

Notes

Dedicated to Professor John L. Stanford on the occasion of his 60th birthday.