Swelling-state-dependent structure of spread microgel monolayers

Journal of Colloid and Interface Science, vol. 718, pp. 140434

Abstract

• Neutron reflectometry elucidates the interfacial structure of thermo-responsive microgel monolayers with nanometer resolution. • The adsorption–collapse pathway governs corona conformation, particle protrusion, and lateral interactions at the interface. • Pathway-dependent interfacial reorganization provides a structural mechanism for tunable microgel-monolayer formation. Albeit largely studied, the interfacial restructuring that governs emulsion breakdown remains poorly understood. Here, we use neutron reflectometry to probe the structure of thermo-responsive microgel monolayers formed either above the volume phase transition temperature or collapsed in situ after adsorption. We find that the thermal history of the microgel critically affects the monolayer architecture, particularly the particle protrusion into the air phase. These insights reveal a pathway-dependent mechanism that governs microgel behavior at interfaces, underpinning the design of next-generation responsive emulsions and interfacial materials.

Authors 7

1. Timon Kratzenberg Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, Aachen, D-52056, Germany

2. Yuri Gerelli corresponding

   Institute for Complex Systems · National Research Council · Sapienza University of Rome

   Affiliation as printed

   Consiglio Nazionale delle Ricerche, Institute for Complex Systems, Piazzale Aldo Moro 2, Rome, ITA-00185, Italy; Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, Rome,ITA-00185, Italy. Electronic address: yuri.gerelli@cnr.it

3. Philipp Gutfreund

   Institut Laue-Langevin

   Affiliation as printed

   Institut Laue-Langevin, Avenue des Martyrs 71, Grenoble, FR-38042, France

4. Pablo Sánchez-Puga

   Institut Laue-Langevin

   Affiliation as printed

   Institut Laue-Langevin, Avenue des Martyrs 71, Grenoble, FR-38042, France

5. Alexander V. Petrunin Aachen Institute of Physical Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, Aachen, D-52056, Germany

6. Walter H. Richtering Aachen Institute of Physical Chemistry DWI - Leibniz Institute for Interactive Materials

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, Aachen, D-52056, Germany; DWI-Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, Aachen, D-52056, Germany

7. Andrea Scotti corresponding

   Lund University

   Affiliation as printed

   Division of Physical Chemistry, Lund University, Lund, SE-22100, Sweden. Electronic address: andrea.scotti@chem.lu.se