Authors: K. Chari, R. Hsu, P. Bhargava, B. Figura, W. Yang, J. Park, T. Clifford, M. Kadir, G. Benedikt
Affilation: Lubrizol Advanced Materials, United States
Pages: 619 - 621
Keywords: microgels, surfactant-activation, yield stress
We describe a new class of nonionic (non-polyelectrolyte) microgels comprising crosslinked amphiphilic copolymers of alkyl acrylates and hydroxyalkyl esters that are activated by surfactant instead of pH. We discuss the mechanism of action of these materials as a combination of swelling of individual polymer particles by surfactant micelles and surfactant-mediated interaction of the swollen microgels using dynamic light scattering (DLS), dynamic rheology and 1H NMR. We demonstrate that it is possible to tailor the composition of the copolymers to combine a high degree of swelling with the mechanical rigidity and inter-particle interactions needed to achieve a high yield stress. In contrast to conventional alkali-swellable polyelectrolyte polymers, very uniform properties (in terms of yield stress, viscosity and optical clarity) are obtained over a broad pH range in surfactant-containing systems enabling elimination of the neutralization step in formulation, improved process efficiency and energy savings.