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Stiffness Tomography of Ultra‐Soft Nanogels by Atomic Force Microscopy
Author(s) -
Schulte M. Friederike,
Bochenek Steffen,
Brugi Monia,
Scotti Andrea,
Mourran Ahmed,
Richtering Walter
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202011615
Subject(s) - stiffness , polymer , materials science , nanotechnology , atomic force microscopy , steric effects , soft materials , chemical physics , soft matter , porosity , composite material , chemical engineering , chemistry , colloid , stereochemistry , engineering
The softness of nanohydrogels results in unique properties and recently attracted tremendous interest due to the multi‐functionalization of interfaces. Herein, we study extremely soft temperature‐sensitive ultra‐low cross‐linked (ULC) nanogels adsorbed to the solid/water interface by atomic force microscopy (AFM). The ultra‐soft nanogels seem to disappear in classical imaging modes since a sharp tip fully penetrates these porous networks with very low forces in the range of steric interactions (ca. 100 pN). However, the detailed evaluation of Force Volume mode measurements allows us to resolve their overall shape and at the same time their internal structure in all three dimensions. The nanogels exhibit an extraordinary disk‐like and entirely homogeneous but extremely soft structure—even softer than polymer brushes. Moreover, the temperature‐sensitive nanogels can be switched on demand between the ultra‐soft and a very stiff state.