Resolving the different bulk moduli within individual soft nanogels using small-angle neutron scattering

Science Advances, vol. 8, pp. eabn6129

Abstract

The bulk modulus, K , quantifies the elastic response of an object to an isotropic compression. For soft compressible colloids, knowing K is essential to accurately predict the suspension response to crowding. Most colloids have complex architectures characterized by different softness, which additionally depends on compression. Here, we determine the different values of K for the various morphological parts of individual nanogels and probe the changes of K with compression. Our method uses a partially deuterated polymer, which exerts the required isotropic stress, and small-angle neutron scattering with contrast matching to determine the form factor of the particles without any scattering contribution from the polymer. We show a clear difference in softness, compressibility, and evolution of K between the shell of the nanogel and the rest of the particle, depending on the amount of cross-linker used in their synthesis.

Authors 11

1. Judith Elizabeth Houston

   European Spallation Source

   Affiliation as printed

   European Spallation Source ERIC, Box 176, SE-221 00 Lund, Sweden

2. Lisa Fruhner

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), 52425 Jülich, Germany

3. Alexis de la Cotte

   Universitat de Barcelona

   Affiliation as printed

   Department of Condensed Matter Physics, University of Barcelona, 08028 Barcelona, Spain

4. Javier González

   Universitat de Barcelona

   Affiliation as printed

   Department of Condensed Matter Physics, University of Barcelona, 08028 Barcelona, Spain

5. Alexander V. Petrunin Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany

6. Urs Gasser

   Paul Scherrer Institute

   Affiliation as printed

   Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen, Switzerland

7. Ralf Schweins

   Institut Laue-Langevin

   Affiliation as printed

   Institut Laue-Langevin ILL DS/LSS, 71 Avenue des Martyrs, F-38000 Grenoble, France

8. Jürgen Allgaier

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science (JCNS-1) and Institute for Biological Information Processing (IBI-8), 52425 Jülich, Germany

9. Walter H. Richtering Aachen Institute of Physical Chemistry

   Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany

   JARA-SOFT, 52056 Aachen, Germany

10. Alberto Fernández‐Nieves

    Institució Catalana de Recerca i Estudis Avançats · Universitat de Barcelona

    Affiliation as printed

    Department of Condensed Matter Physics, University of Barcelona, 08028 Barcelona, Spain

    ICREA-Institucio Catalana de Recerca i Estudis Avancats, 08010 Barcelona, Spain

11. Andrea Scotti corresponding Aachen Institute of Physical Chemistry

    RWTH Aachen University

    Affiliation as printed

    Institute of Physical Chemistry, RWTH Aachen University, 52056 Aachen, Germany