Université de Fribourg

Accounting for effective interactions among charged microgels

Aguirre-Manzo, L. A. ; Ledesma-Motolinía, Mónica ; Rojas-Ochoa, Luis Fernando ; Trappe, Véronique ; Callejas-Fernández, J. ; Haro-Pérez, Catalina ; González-Mozuelos, P.

In: Physical Review E, 2019, vol. 100, no. 3, p. 032602

We introduce a theoretical approach to describe structural correlations among charged permeable spheres at finite particle concentrations. This theory explicitly accounts for correlations among microions and between microions and macroions and allows for the proposal of an effective interaction among macroions that successfully captures structural correlations observed in poly- N -isopropyl...

Université de Fribourg

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

Braibanti, Marco ; Haro-Pérez, Catalina ; Quesada-Pérez, M. ; Rojas-Ochoa, Luis Fernando ; Trappe, Véronique

In: Physical Review E, 2016, vol. 94, no. 3, p. 032601

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...

Université de Fribourg

Interplay between internal structure and optical properties of thermosensitive nanogels

Ledesma-Motolinía, Mónica ; Braibanti, Marco ; Rojas-Ochoa, Luis F. ; Haro-Pérez, Catalina

In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2015, vol. 482, p. 724–727

The structural and optical properties of thermosensitive particles, nanogels, are studied by light scattering and refractometry as a function of temperature. Nanogels are composed of poly- N-Isopropopylacrylamide, a polymer that shrinks at temperatures higher than its lower critical solution temperature, 33 °C. The internal nanogel structure obtained by light scattering is well modeled by...