Journal Article

PUBDB-2023-06030

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png In-situ aggregation and early states of gelation of gold nanoparticle dispersions

Schulz, F. (Corresponding author)Extern* ; Jain, A.Extern*XFEL.EU*DESY* ; Dallari, F.XFEL.EU*DESY* ; Markmann, V.XFEL.EU*DESY* ; Lehmkühler, F. (Corresponding author)XFEL.EU*DESY*

2024
Royal Soc. of Chemistry London

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Please use a persistent id in citations: doi:10.1039/D4SM00080C  doi:10.3204/PUBDB-2023-06030

Abstract: 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.

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Contributing Institute(s):

1. Spectroscopy of molecular processes (FS-SMP)
2. Coherent X-ray Scattering (FS-CXS)

Research Program(s):

1. 633 - Life Sciences – Building Blocks of Life: Structure and Function (POF4-633) (POF4-633)
2. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
3. FS-Proposal: I-20190529 (I-20190529) (I-20190529)
4. Ex-Net-0002-Phase2-3 - Advanced Imaging of Matter: Structure, Dynamics and Control on the Atomic Scale - AIM (2018_Ex-Net-0002-Phase2-3) (2018_Ex-Net-0002-Phase2-3)

Experiment(s):

1. PETRA Beamline P10 (PETRA III)
2. Measurement at external facility

Appears in the scientific report 2024

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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