Pérez-González, J.; Muñoz-Castro, Y.; Rodríguez-González, F.; Marín-Santibáñez, B.M.; Medina-Bañuelos, E.F. Influence of Sonication on the Molecular Characteristics of Carbopol® and Its Rheological Behavior in Microgels. Gels2024, 10, 420.
Pérez-González, J.; Muñoz-Castro, Y.; Rodríguez-González, F.; Marín-Santibáñez, B.M.; Medina-Bañuelos, E.F. Influence of Sonication on the Molecular Characteristics of Carbopol® and Its Rheological Behavior in Microgels. Gels 2024, 10, 420.
Pérez-González, J.; Muñoz-Castro, Y.; Rodríguez-González, F.; Marín-Santibáñez, B.M.; Medina-Bañuelos, E.F. Influence of Sonication on the Molecular Characteristics of Carbopol® and Its Rheological Behavior in Microgels. Gels2024, 10, 420.
Pérez-González, J.; Muñoz-Castro, Y.; Rodríguez-González, F.; Marín-Santibáñez, B.M.; Medina-Bañuelos, E.F. Influence of Sonication on the Molecular Characteristics of Carbopol® and Its Rheological Behavior in Microgels. Gels 2024, 10, 420.
Abstract
The effect of sonication on the molecular characteristics of poliacrylic acid (Carbopol® Ultrez 10) and its rheological behavior in aqueous dispersions and microgels containing 0.25 wt. % of the polymer was analyzed in this work by rheometry, weight-average molecular weight (Mw) measurements via static light scattering (SLS), Fourier transform infrared (FTIR) spectroscopy and confocal microscopy. For this, the precursor dispersion and the microgels were sonicated in a commercial ultrasound bath at constant power and different times. We observed a softening of the microgel microstructure consisting of a systematic decrease in its shear modulus, yield stress and viscosity with increasing sonication time, while their overall Herschel-Bulkley (H-B) behavior was preserved. SLS measurements evidenced a reduction of Mw of polyacrylic acid with sonication time. Separately, FTIR measurements indicate that sonication produces scission in the C-C links of the Carbopol® backbone, which results in chains with the same chemistry but lower molecular weight. Finally, confocal microscopy measurements revealed a concomitant diminution of the size of the microsponge domains with sonication time, which is reflected in a softer microstructure resulting from reduction of the molecular weight of polyacrylic acid. The present results indicate that both the microstructure and the rheological behavior of Carbopol® microgels, in particular, and complex fluids in general, may be manipulated or tailored by high-power ultrasonication.
Chemistry and Materials Science, Polymers and Plastics
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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