Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 21: Focus: Smart Hydrogels and Hydrogel Based Devices I - organized by Gerald Gerlach, Walter Richtering and Thomas Hellweg
CPP 21.1: Topical Talk
Dienstag, 13. März 2018, 09:30–10:00, C 130
Superresolution microscopy of pNIPAM microgels — •Frank Scheffold1, Gaurasundar Marc Conley1, Philippe Aebischer2, Sofi Nöjd2, Marco Braibanti1, and Peter Schurtenberger2 — 1Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland — 2Physical Chemistry, Department of Chemistry, Lund University, 221 00 Lund, Sweden
Microgels are among the most studied colloidal and polymeric systems of the past two decades. Swelling thermosensitive, poly(N-isopropylacrylamide) microgels by lowering the temperature provides a unique mechanism for controlling the porosity and size of colloidal particles on the nanoscale. As a consequence, these smart microgel particles are being considered for applications ranging from viscosity modifiers and sensing to drug delivery and as models for the glass and the jamming transition. Here, we present results from in-situ two-color superresolution microscopy of dye-labelled submicron sized pNiPAM microgels. We first demonstrate direct STochastic Optical Reconstruction Microscopy (dSTORM) to image single microgels in two and three dimensions, at different stages of the volume phase transition, with a lateral resolution of 30nm. We find that the swelling behaviour observed in real space matches quantitatively with results from traditional light scattering measurements in reciprocal space. Next, we study dye labelled tracer microgels embedded in dense microgel suspensions. As we increase the packing density we map out the different contributions that allow the dense packing of the soft microgels, due to deformation, interpenetration and compression.