%0 Journal Article %T Gelation and Re-entrance in Mixtures of Soft Colloids and Linear Polymers of Equal Size %+ University of Groningen [Groningen] %+ Institute of Electronic Structure and Laser (FORTH-IESL) %+ Laboratoire Charles Coulomb (L2C) %+ University of Houston %+ Argonne National Laboratory [Lemont] (ANL) %+ Department of Chemistry [Waterloo] %A Parisi, Daniele %A Truzzolillo, Domenico %A Slim, Ali %A Dieudonné-George, Phillippe %A Narayanan, Suresh %A Conrad, Jacinta %A Deepak, Vishnu %A Gauthier, Mario %A Vlassopoulos, Dimitris %< avec comité de lecture %@ 0024-9297 %J Macromolecules %I American Chemical Society %V 56 %N 5 %P 1818-1827 %8 2023 %D 2023 %Z 2212.05992 %R 10.1021/acs.macromol.2c02491 %K Colloids %K Polymer %K Gels %K Rheology %Z Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft] %Z Chemical Sciences/PolymersJournal articles %X Liquid mixtures composed of colloidal particles and much smaller non-adsorbing linear homopolymers can undergo a gelation transition due to polymer-mediated depletion forces. We now show that the addition of linear polymers to suspensions of soft colloids having the same hydrodynamic size yields a liquid-to-gel-to-re-entrant liquid transition. In particular, the dynamic state diagram of 1,4-polybutadiene star–linear polymer mixtures was determined with the help of linear viscoelastic and small-angle X-ray scattering experiments. While keeping the star polymers below their nominal overlap concentration, a gel was formed upon increasing the linear polymer content. Further addition of linear chains yielded a re-entrant liquid. This unexpected behavior was rationalized by the interplay of three possible phenomena: (i) depletion interactions, driven by the size disparity between the stars and the polymer length scale which is the mesh size of its entanglement network; (ii) colloidal deswelling due to the increased osmotic pressure exerted onto the stars; and (iii) a concomitant progressive suppression of the depletion efficiency on increasing the polymer concentration due to reduced mesh size, hence a smaller range of attraction. Our results unveil an exciting new way to tailor the flow of soft colloids and highlight a largely unexplored path to engineer soft colloidal mixtures. %G English %2 https://hal.science/hal-04035012/document %2 https://hal.science/hal-04035012/file/2212.05992.pdf %L hal-04035012 %U https://hal.science/hal-04035012 %~ CNRS %~ OPENAIRE %~ L2C %~ UNIV-MONTPELLIER %~ UM-2015-2021 %~ UM-EPE