We combine small-angle scattering experiments and simulations to investigate the internal structure and interactions of composite poly(N-isopropylacrylamide)-poly(ethylene glycol) (PNIPAM-PEG) microgels. At low temperatures the experimentally determined form factors and the simulated density profiles indicate a loose internal particle structure with an extended corona that can be modeled as a starlike object. With increasing temperature across the volumetric phase transition, the form factor develops an inflection that, using simulations, is interpreted as arising from a conformation in which PEG chains are incorporated in the interior of the PNIPAM network. This gives rise to a peculiar density profile characterized by two dense, separated regions, at odds with configurations in which the PEG chains reside on the surface of the PNIPAM core. The conformation of the PEG chains also have profound effects on the interparticle interactions: Although chains on the surface reduce the solvophobic attraction typically experienced by PNIPAM particles at high temperatures, PEG chains inside the PNIPAM network shift the onset of attractive interaction at even lower temperatures. Our results show that by tuning the morphology of the composite microgels, we can qualitatively change both their structure and their mutual interactions, opening the way to explore new collective behaviors of these objects.

Link between Morphology, Structure, and Interactions of Composite Microgels / Rivas-Barbosa, R.; Ruiz-Franco, J.; Lara-Pena, M. A.; Cardellini, J.; Licea-Claverie, A.; Camerin, F.; Zaccarelli, E.; Laurati, M.. - In: MACROMOLECULES. - ISSN 0024-9297. - 55:5(2022), pp. 1834-1843. [10.1021/acs.macromol.1c02171]

Link between Morphology, Structure, and Interactions of Composite Microgels

Rivas-Barbosa R.
Co-primo
;
Camerin F.;Zaccarelli E.;
2022

Abstract

We combine small-angle scattering experiments and simulations to investigate the internal structure and interactions of composite poly(N-isopropylacrylamide)-poly(ethylene glycol) (PNIPAM-PEG) microgels. At low temperatures the experimentally determined form factors and the simulated density profiles indicate a loose internal particle structure with an extended corona that can be modeled as a starlike object. With increasing temperature across the volumetric phase transition, the form factor develops an inflection that, using simulations, is interpreted as arising from a conformation in which PEG chains are incorporated in the interior of the PNIPAM network. This gives rise to a peculiar density profile characterized by two dense, separated regions, at odds with configurations in which the PEG chains reside on the surface of the PNIPAM core. The conformation of the PEG chains also have profound effects on the interparticle interactions: Although chains on the surface reduce the solvophobic attraction typically experienced by PNIPAM particles at high temperatures, PEG chains inside the PNIPAM network shift the onset of attractive interaction at even lower temperatures. Our results show that by tuning the morphology of the composite microgels, we can qualitatively change both their structure and their mutual interactions, opening the way to explore new collective behaviors of these objects.
colloids; microgels; pnipam; soft matter
01 Pubblicazione su rivista::01a Articolo in rivista
Link between Morphology, Structure, and Interactions of Composite Microgels / Rivas-Barbosa, R.; Ruiz-Franco, J.; Lara-Pena, M. A.; Cardellini, J.; Licea-Claverie, A.; Camerin, F.; Zaccarelli, E.; Laurati, M.. - In: MACROMOLECULES. - ISSN 0024-9297. - 55:5(2022), pp. 1834-1843. [10.1021/acs.macromol.1c02171]
File allegati a questo prodotto
File Dimensione Formato  
Rivas-Barbosa_Link between Morphology_2022.pdf

accesso aperto

Tipologia: Altro materiale allegato
Licenza: Creative commons
Dimensione 1.72 MB
Formato Adobe PDF
1.72 MB Adobe PDF Visualizza/Apri PDF

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1616554
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 2
  • ???jsp.display-item.citation.isi??? 2
social impact