Université de Fribourg

The liquid-glass-jamming transition in disordered ionic nanoemulsions

Braibanti, Marco ; Kim, Ha Seong ; ªenbil, Nesrin ; Pagenkopp, Matthew J. ; Mason, Thomas G. ; Scheffold, Frank

In: Scientific Reports, 2017, vol. 7, no. 1, p. 13879

In quenched disordered out-of-equilibrium many-body colloidal systems, there are important distinctions between the glass transition, which is related to the onset of nonergodicity and loss of low-frequency relaxations caused by crowding, and the jamming transition, which is related to the dramatic increase in elasticity of the system caused by the deformation of constituent objects. For...

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

Superresolution microscopy of the volume phase transition of pNIPAM microgels

Conley, Gaurasundar M. ; Nöjd, Sofi ; Braibanti, Marco ; Schurtenberger, Peter ; Scheffold, Frank

In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2016, vol. 499, p. 18–23

Hierarchical polymer structures such as pNIPAM microgels have been extensively studied for their ability to undergo structural and physical transformations that can be controlled by external stimuli such as temperature, pH or solvent composition. However, a direct three-dimensional visualization of individual particles in-situ has so far been hindered by insufficient resolution, with optical...

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...