Structural investigation of Carbopol ETD2050 by light scattering

Carbopol, a family of cross-linked acrylic acid-based polymers and a well-known thickener used in personal care, household and industrial products, is often used as a model yield-stress fluid because it is transparent and its rheological properties can be precisely tuned by sample preparation conditions. Carbopol dispersions behave as an elastic solid, but they will flow when the applied stress exceeds a sample-dependent yield value. Both the yield-stress phenomena and the range of potential applications motivate the study of the microscopic structure and properties of yield-stress fluids. These investigation will lead to a fundamental understanding of the yield-stress phenomenon of Carbopol. Light scattering experiments investigating Carbopol ETD2050 dispersed in water have revealed that the Carbopol microstructure consists of a small and a large length scale, possibly described by different cross-linking densities. Experiments also show that the length scales and mass fractal dimension depend on the sample concentration and pH.