Carbopol gels: Elastoviscoplastic and slippery glasses made of individual swollen sponges: Meso- and macroscopic properties, constitutive equations and scaling laws

Abstract This paper gives details of new data on neutralized Carbopol 940 dispersions. Appropriate techniques have been used to characterize the physical properties of the bulk gel and inter-phase slip at the wall. Previously published data are analysed and used wherever possible. Terminology and measurement difficulties are also addressed. The structure of Carbopol dispersions can be described in terms of polydisperse glasses made of individual swollen hydrophylic elastic sponges. They display elastoplasticity, and significant dissipation both below and above their yield stress. Hardly any creep was observed over 10 months of experiments. Scaling laws are proposed for Carbopol mechanical properties as a function of concentration. Carbopol behaviour varies with the value of concentration, and in particular when comparing percolation concentration with close-packing concentration. Constitutive equations for bulk shear stresses and for friction slip at the wall can be deduced from contact mechanics which fit rheometry data and scaling laws. Herschel–Bulkley constitutive equations may be used by ignoring elasticity, normal shear stresses and transients.

[1]  Howard A. Barnes,et al.  The yield stress—a review or ‘παντα ρει’—everything flows? , 1999 .

[2]  S. Park,et al.  Rheological properties and microstructures of Carbopol gel network system , 2003 .

[3]  B. W. Barry,et al.  The rheological properties of carbopol gels I. Continuous shear and creep properties of carbopol gels , 1979 .

[4]  A. Cemal Eringen,et al.  Mechanics of continua , 1967 .

[5]  E. B. Bagley,et al.  Dispersions or solutions? A mechanism for certain thickening agents , 1974 .

[6]  Laurent Jossic,et al.  Spheres and interactions between spheres moving at very low velocities in a yield stress fluid , 2006 .

[7]  C. R. Calladine,et al.  Plasticity for engineers , 1985 .

[8]  Howard A. Barnes,et al.  The yield stress myth? , 1985 .

[9]  B. W. Barry,et al.  The rheological properties of carbopol gels II. Oscillatory properties of carbopol gels , 1979 .

[10]  W. Vaz,et al.  Chapter 6 - Lateral Diffusion in Membranes , 1995 .

[11]  G. B. Froishteter,et al.  The flow of plastic disperse systems in the presence of the wall effect , 1975 .

[12]  J. Hartnett,et al.  Technical note: The yield stress—An engineering reality , 1989 .

[13]  H. Barnes,et al.  New measurements of the flow-curves for Carbopol dispersions without slip artefacts , 2001 .

[14]  S. Wiberley,et al.  Yield Stresses and Flow Properties of Carboxypolymethylene‐Water Systems , 1961 .

[15]  J. Piau,et al.  Shear elasticity and yield stress of silica–silicone physical gels: Fractal approach , 1999 .

[16]  P. Coussot,et al.  Rheology of concentrated dispersed systems in a low molecular weight matrix , 1993 .

[17]  H. W. Veen,et al.  Handbook of Biological Physics , 1996 .

[18]  R. Prud’homme,et al.  Rheology of concentrated microgel solutions , 1988 .

[19]  Daniel De Kee,et al.  Non-Newtonian fluids with a yield stress , 2005 .

[20]  C. Tiu,et al.  The shear-induced solid–liquid transition in yield stress materials with chemically different structures , 2005 .

[21]  P. Molyneux.  Water-soluble synthetic polymers: properties and behavior , 1983 .

[22]  Letter to the Editor: Comment on “Origin of concentric cylinder viscometry” [J. Rheol. 49, 807–818 (2005)]. The relevance of the early days of viscosity, slip at the wall, and stability in concentric cylinder viscometry , 2005 .

[23]  M. Mooney.  CHAPTER 5 – THE RHEOLOGY OF RAW ELASTOMERS , 1958 .

[24]  M. R. Mackley,et al.  Theoretical and applied rheology: Vols 1 & 2, edited by P. Moldenaers & R. Keunings. Elsevier, New York (1992). ISBN 0-444-89007-6. US$340 , 1993 .

[25]  Frederick R. Eirich,et al.  Rheology : theory and applications , 1956 .

[26]  D. Moore,et al.  Principles and Applications of Tribology , 1976 .

[27]  Andras Z. Szeri,et al.  Fluid Film Lubrication: Theory and Design , 1998 .

[28]  A. Magnin,et al.  Cone-and-plate rheometry of yield stress fluids. Study of an aqueous gel , 1990 .

[29]  Jason R. Stokes,et al.  Measuring the yield behaviour of structured fluids , 2004 .

[30]  O. Axner,et al.  Design for fully steerable dual-trap optical tweezers. , 1997, Applied optics.

[31]  J. Davidson,et al.  Poly(acrylic acid) Thickeners: The Importance of Gel Microrheology and Evaluation of Hydrophobically Modified Derivatives as Emulsifiers , 1989 .