• Categoría: Artículo
  • Título: Impact of volume transition on the net charge of poly-N-isopropyl acrylamide microgels
  • Autor (es): M. Braibanti, C. Haro-Pérez, M. Quesada-Pérez, L. F. Rojas-Ochoa, and V. Trappe
  • Revista: Physical Review E
  • Volumen: 94
  • Páginas: 032601
  • Formato: Enlace
  • Subido por: Catalina Ester

Impact of volume transition on the net charge of poly-N-isopropyl acrylamide microgels

M. Braibanti, C. Haro-Pérez, M. Quesada-Pérez, L. F. Rojas-Ochoa, and V. Trappe

We explore the electrostatic properties of poly-N-isopropyl acrylamide microgels in dilute, quasi-de-ionized
dispersions and show that the apparent net charge of these thermosensitive microgels is an increasing function
of their size, the size being conveniently varied by temperature. Our experimental results obtained in a
combination of light scattering, conductivity, and mobility experiments are consistent with those obtained in
Poisson-Boltzmann cell model calculations, effectively indicating that upon shrinking the number of counterions
entrapped within the microgels increases. Remarkably, this behavior shows that the electrostatic energy per
particle remains constant upon swelling or deswelling the microgel, resulting in a square root dependence of the
net charge on the particle radius.