Université de Fribourg

Characterizing nanoparticles in complex biological media and physiological fluids with depolarized dynamic light scattering

Balog, Sandor ; Rodriguez-Lorenzo, Laura ; Monnier, Christophe A. ; Obiols-Rabas, Marc ; Rothen-Rutishauser, Barbara ; Schurtenberger, Peter ; Petri-Fink, Alke

In: Nanoscale, 2015, p. -

Light scattering is one of the few techniques available to adequately characterize suspended nanoparticles (NPs) in real time and in situ. However, when it comes to NPs in multicomponent and optically complex aqueous matrices – such as biological media and physiological fluids – light scattering suffers from lack of selectivity, as distinguishing the relevant optical signals from the...

Université de Fribourg

Correlation between morphology, water uptake, and proton conductivity in radiation-grafted proton-exchange membranes

Balog, Sandor ; Gasser, Urs ; Mortensen, Kell ; Gubler, Lorenz ; Scherer, Guenther G. ; youcef, Hicham Ben

In: Macromolecular Chemistry and Physics, 2010, vol. 211, no. 6, p. 635-643

An SANS investigation of hydrated proton exchange membranes is presented. Our membranes were synthesized by radiation-induced grafting of ETFE with styrene in the presence of a crosslinker, followed by sulfonation of the styrene. The contrast variation method was used to understand the relationship between morphology, water uptake, and proton conductivity. The membranes are separated into two...

Université de Fribourg

Photocount statistics in mesoscopic optics

Balog, Sandor ; Zakharov, Pavel ; Scheffold, Frank ; Skipetrov, S. E.

In: Physical Review Letters, 2006, vol. 97, p. 103901

We report the first observation of the impact of mesoscopic fluctuations on the photocount statistics of coherent light scattered in a random medium. A Poisson photocount distribution of the incident light widens and gains additional asymmetry upon transmission through a suspension of small dielectric spheres. The effect is only appreciable when the average number of photocounts becomes...