TY  - JOUR
AU  - Schulz, Florian
AU  - Jain, Avni
AU  - Dallari, Francesco
AU  - Markmann, Verena
AU  - Lehmkühler, Felix
TI  - In-situ aggregation and early states of gelation of gold nanoparticle dispersions
JO  - Soft matter
VL  - 20
IS  - 18
SN  - 1744-683X
CY  - London
PB  - Royal Soc. of Chemistry
M1  - PUBDB-2023-06030
SP  - 3836-3844
PY  - 2024
AB  - The aggregation and onset of gelation of PEGylated gold nanoparticles dispersed in a glycerol–water mixture is studied by small-angle X-ray scattering and X-ray photon correlation spectroscopy. Tracking structural dynamics with sub-ms time resolution over a total experimental time of 8 hours corresponding to a time windows larger than 108 Brownian times and varying the temperature between 298 K and 266 K we can identify three regimes. First, while cooling to 275 K the particles show Brownian motion that slows down due to the increasing viscosity. Second, upon further cooling the static structure changes significantly, indicated by a broad structure factor peak. We attribute this to the formation of aggregates while the dynamics are still dominated by single-particle diffusion. Finally, the relaxation functions become more and more stretched accompanied by an increased slow down of the dynamics. At the same time the structure changes continuously indicating the onset of gelation. Our observations further suggest that the colloidal aggregation and gelation is characterized first by structural changes with a subsequent slowing down of the systems dynamics. The analysis also reveals that the details of the gelation process and the gel structure strongly depend on the thickness of the PEG-coating of the gold nanoparticles. 
LB  - PUB:(DE-HGF)16
C6  - 38651356
UR  - <Go to ISI:>//WOS:001206309900001
DO  - DOI:10.1039/D4SM00080C
UR  - https://bib-pubdb1.desy.de/record/594921
ER  -