Soft and Responsive: Rheological Insights into PNIPAM based Microgels
| When |
Jul 09, 2024
from 11:00 to 12:00 |
|---|---|
| Where | Salle des thèses |
| Attendees |
Roberta Angelini |
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Microgels are soft particles made by cross-linked polymer networks with a hybrid nature between that of polymers and colloids. They are widely used as a colloidal model system because of their swelling properties and their responsivity to external control parameters such as temperature or pH. The phase behaviour of microgels has attracted great attention thanks to the large variety of new phenomenology emerging from their ability to pack at very high volume fractions. Combining rheology [1,2], x-ray photon correlation spectroscopy [3], and small angle x-ray scattering, we perform an extensive experimental study of a thermo- and pH-sensitive microgel composed of Interpenetrated Polymer Network (IPN) of poly(N-isopropylacrylamide) (PNIPAM) and poly(acrylic acid) (PAAc) at fixed PAAc content as a function of weight concentration with the ultimate goal of understanding its complex phase behavior. We distinguish three different rheological regimes, characteristic of three different states: liquid, glass and jammed, the possible molecular mechanisms driving the formation of these states is discussed [1] and a preliminary T- Cw phase diagram is drawn [4].
- S. Franco, E. Buratti, V. Nigro, E. Zaccarelli, B. Ruzicka, R. Angelini, Int. J. Mol. Sci. 22 (8), 4032 (2021)
- S Franco, E Buratti, B Ruzicka, V Nigro, N Zoratto, P Matricardi, E Zaccarelli, R Angelini, J. Phys.Condens. Matter 33 (17), 174004 (2021)
- V. Nigro, B. Ruzicka, B. Ruta, F. Zontone, M. Bertoldo, E. Buratti and R. Angelini, Macromolecules 53, 1596−1603 (2020)
- S Franco, E Buratti, V Nigro, M Bertoldo, B Ruzicka, R Angelini, Polymers 14 (1), 115 (2022)