Phase behavior of silica-PNIPAm nanogels under high hydrostatic pressure
The structure and dynamics of concentrated silica-PNIPAm (poly-<i>N</i>-iso-prop-yl-acrylamide) nanogels are studied as a function of hydrostatic pressure up to 3500 bar. A combination of X-ray photon correlation spectroscopy and small-angle X-ray scattering shows similar characteristics of the dynamics for both temperature- and pressure-induced volume phase transitions of PNIPAm nanogels. Upon increasing the pressure and depending on the initial particle volume fraction, a transition from a liquid or glass state to a colloidal gel is observed for pressures <i>p</i> ≃ 1500 bar at a temperature of 293 K. Time-dependent analysis of the dynamics shows aging in glass and gel samples which is absent in the liquid state. This indicates stress-dominated dynamics upon pressure changes that equilibrate after a few hundred seconds.
Authors
- Christina Krywka (ORCID: https://orcid.org/0000-0003-2940-3359)
- Claudia Goy
- Niels C. Gießelmann (ORCID: https://orcid.org/0009-0002-8139-4357)
- Nele N. Striker (ORCID: https://orcid.org/0000-0001-9429-0835)
- Svenja C. Hövelmann (ORCID: https://orcid.org/0000-0001-5533-6714)
- Florian Schulz (ORCID: https://orcid.org/0000-0003-4440-3680)
- Michael Paulus (ORCID: https://orcid.org/0000-0002-3409-6798)
- Irina Lokteva (ORCID: https://orcid.org/0000-0002-2286-477X)
- Frédéric Caupin (ORCID: https://orcid.org/0000-0002-8892-2514)
- Fabian Westermeier (ORCID: https://orcid.org/0000-0003-0696-206X)
- Felix Lehmkühler (ORCID: https://orcid.org/0000-0003-1289-995X)
Institutions
- Université Claude Bernard Lyon 1 (FR)
- Centre National de la Recherche Scientifique (FR)
- Universität Hamburg (DE)
- TU Dortmund University (DE)
- Deutsches Elektronen-Synchrotron DESY (DE)
- Hochschule für Angewandte Wissenschaften Kiel (DE)
- Institut Lumière Matière (FR)
- Helmholtz-Zentrum Hereon (DE)
- Max Planck Institute for the Structure and Dynamics of Matter (DE)
- Hamburg Centre for Ultrafast Imaging
Publication Details
- Journal
- Journal of Applied Crystallography
- Published
- 2025-04-29
- DOI
- https://doi.org/10.1107/s1600576725003188
- Citations
- 1
- Primary Topic
- Mesoporous Materials and Catalysis
- Type
- article
- Field-Weighted Citation Impact
- 0.52
Funders
- Deutsches Elektronen-Synchrotron